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Real World Multicore Embedded Systems 1st Edition
Bryon Moyer Digital Instant Download
Author(s): Bryon Moyer
ISBN(s): 9780124160187, 0124160182
Edition: 1
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Year: 2013
Language: english
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Real World Multicore Embedded Systems
A Practical Approach, Expert Guide
Bryon Moyer
Table of Contents
Cover image
Title page
Copyright
About the Editor
About the Authors
Chapter 1. Introduction and Roadmap
Multicore is here
Scope
Who should read this book?
Organization and roadmap
A roadmap of this book
Chapter 2. The Promise and Challenges of Concurrency
Concurrency fundamentals
Two kinds of concurrency
Dependencies
Loops and dependencies
Shared resources
Summary
Chapter 3. Multicore Architectures
The need for multicore architectures
Multicore architecture drivers
Traditional sequential software paradigms break
Scope of multicore hardware architectures
Basic multicore hardware architecture overview
Specific multicore architecture characteristics
Processing architectures
ALU processing architectures
Lightweight processing architectures
Mediumweight processing architectures
Heavyweight processing architectures
Communication architectures
Memory architectures
Application specificity
Application-specific platform topologies
Integration of multicore systems, MPSoCs and sub-systems
Programming challenges
Application characteristics
MPSoC analysis, debug and verification
Shortcomings and solutions
MPSoC parallel programming
Parallel software and MPSoCs
Summary
References
Chapter 4. Memory Models for Embedded Multicore Architecture
Introduction
Memory types
Memory architecture
Memory structure of multicore architecture
Cache coherency
Transactional memory
Summary
References
Chapter 5. Design Considerations for Multicore SoC
Interconnections
Introduction
Communication activity in multicore SoCs
Functional requirements and topologies of SoC traffic
Performance considerations
Interconnection networks: representation and terminology
Bus as an SoC interconnection
Fabric-oriented interconnects for larger SoCs
Building blocks of scalable interconnections
Evaluating and comparing interconnection topologies for future
SoCs
A survey of interconnection networks suitable for future SoCs
Some practical considerations in designing interconnections
Summary
References
Further reading
Chapter 6. Operating Systems in Multicore Platforms
Introduction
Symmetric multiprocessing systems and scheduling
Assymetric multiprocessor systems
Virtualization
Controlling OS behavior
Debugging a multicore system
Summary
Reference
Chapter 7. System Virtualization in Multicore Systems
What is virtualization?
A brief retrospective
Applications of system virtualization
Hypervisor architectures
Leveraging hardware assists for virtualization
Hypervisor robustness
I/O Virtualization
Case study: power architecture virtualization and the freescale
P4080
Example use cases for system virtualization
Conclusion
References
Chapter 8. Communication and Synchronization Libraries
Introduction
Library overview and basics
Explicit threading libraries
OpenMP
Threading Building Blocks
Boost Threads
MCAPI
Conclusion
References
Chapter 9. Programming Languages
Programming languages for multicore embedded systems
C
Assembly language
C++
Java
Python
Ada
Summary
References
Chapter 10. Tools
Introduction
Real-Time operating systems (RTOS)
Communication tools
Parallelizing serial software tools
Software development and debug tools
Benchmarking tools
Conclusion
Acknowledgments
Chapter 11. Partitioning Programs for Multicore Systems
Introduction
What level of parallelism?
The basic cost of partitioning
A high-level partitioning algorithm
The central role of dependencies
Critical sections
Synchronizing data
Implementing a partitioning strategy
Using tools to simplify partitioning
Summary
References
Chapter 12. Software Synchronization
Introduction
Why is synchronization required?
Problems with not synchronizing (or synchronizing badly)
Testing for proper synchronization
How is synchronization achieved?
Specific conditions requiring synchronization
Language support for implementation
Patterns
Side-effects of synchronization
Hardware and OS effects on synchronization
Problems when trying to implement synchronization
References
Chapter 13. Hardware Accelerators
Introduction
Architectural considerations
The interface: registers, drivers, APIs, and ISRs
Initialization
Operating system considerations
Coherency
Making the architectural decisions
Video example
Summary
Chapter 14. Multicore Synchronization Hardware
Chapter overview
Instruction set support for synchronization
Hardware support for synchronization
Hardware support for lock-free programming
Memory subsystem considerations
Conclusions
References
Chapter 15. Bare-Metal Systems
Introduction
Architectural arrangements
Software architecture
Building the executable image(s)
Example: IPv4 forwarding
Conclusion
Reference
Chapter 16. Multicore Debug
Introduction – why debug instrumentation
Background – silicon debug and capabilities
Trace methods for multicore debug analysis
Debug flows and subsystems
Commercial approaches
The future of multicore debug
References
Further reading
Index
Copyright
Newnes is an imprint of Elsevier
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225 Wyman Street, Waltham, MA 02451, USA
First published 2013
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Notices
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Practitioners and researchers must always rely on their own
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A catalog record for this book is available from the Library of
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ISBN: 978-0-12-416018-7
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About the Editor
Bryon Moyer, Technology Writer and Editor, EE Journal,
bryon@moyerwriting.com
Bryon Moyer is a technology writer and an editor/writer for EE
Journal. He has over 30 years’ experience as an engineer and
marketer in Silicon Valley, having worked for MMI, AMD, Cypress,
Altera, Actel, Teja Technologies, and Vector Fabrics. He has
focused on PLDs/FPGAs, EDA, embedded systems, multicore
processing, networking protocols, and software analysis. He has a
BSEE from UC Berkeley and an MSEE from Santa Clara University.
About the Authors
Jim Holt, Systems Architect for Freescale’s Networking and Multimedia
group, Austin, TX, USA, RWBL70@freescale.com
Dr. Jim Holt is a Systems Architect for Freescale’s Networking and
Multimedia group, and is also a Research Affiliate at the
Massachusetts Institute of Technology where he is investigating
self-aware 1000-core chips of the future. He has 29 years of
industry experience focused on microprocessors, multicore systems,
software engineering, distributed systems, design verification, and
design optimization. He earned a Ph.D. in Electrical and Computer
Engineering from the University of Texas at Austin, and an MS in
Computer Science from Texas State University-San Marcos.
John Carbone jcarbone@expresslogic.com
John A. Carbone, vice president of marketing for Express Logic,
has 35 years experience in real-time computer systems and
software, ranging from embedded system developer and FAE to
vice president of sales and marketing. Mr. Carbone’s experience
includes embedded computers, array processors, attached
processors, development tools, and both commercial and
proprietary real-time operating systems. Mr. Carbone has a BA
degree in mathematics from Boston College.
William Lamie blamie@expresslogic.com
William E. Lamie is co-founder and CEO of Express Logic, Inc.,
and is the author of the ThreadX® RTOS. Prior to founding
Express Logic, Mr. Lamie was the author of the Nucleus™ RTOS
and co-founder of Accelerated Technology, Inc. Mr. Lamie has over
25 years’ experience in embedded systems development, over 20
of which are in the development of real-time operating systems
for embedded applications. He has a BS in Computer Science
from San Diego State University.
Max Domeika, Technical Project Manager, Intel Corporation, Intel
Corporation, Hillsboro, OR, USA, max.j.domeika@intel.com
Max Domeika is a technical product manager at Intel Corporation
working on HTML5. Over the past 16 years, Max has held several
positions in compiler and software tools development. Max earned
a BS in Computer Science from the University of Puget Sound, an
MS in Computer Science from Clemson University, and a MS in
Management in Science & Technology from Oregon Graduate
Institute. Max is the author of Software Development for
Embedded Multi-core Systems from Elsevier and Break Away with
Intel® AtomTM Processors from Intel Press.
Kenn Luecke kenn.r.luecke@boeing.com
Kenn Luecke currently works in Boeing Test & Evaluation in the
Vehicle Management Subsystem Labs. He has 23 years of
experience in network systems, avionics system, multicore and
parallel embedded software development, mission-critical
computing, and security. He has a Bachelor’s degree in Computer
Science from the University of Missouri-St. Louis and a Masters of
Business Administration from Washington University in St. Louis.
Neal Stollon, Principal Engineer with HDL Dynamics, Dallas, TX,
USA, neals@hdldynamics.com
Dr. Neal Stollon is Principal Engineer with HDL Dynamics, which
provides on-chip digital IP consulting, integration, and analysis
services for SoC design. Dr. Stollon is chairman of the Nexus
5001 Forum, a consortium developing standards based on-chip
instrument solutions, and is also co-chair of the OCP-IP Debug
Working Group, which also addresses SoC debug requirements. Dr.
Stollon has a Ph.D in EE from Southern Methodist University and
is author of the book “On-Chip Instrumentation”.
Yosinori Watanabe, Senior Architect, Cadence Design Systems,
Berkeley, CA, USA, watanabe@cadence.com
Dr. Yosinori Watanabe is a Senior Architect at Cadence Design
Systems. He has 21 years of experience in microprocessor design,
embedded system design, logic and behavioral synthesis, and the
design and verification of embedded systems and software. He
has a Ph.D. in Electrical Engineering and Computer Sciences from
the University of California at Berkeley.
Paul Stravers, Chief Architect and Co-founder of Vector Fabrics
Dr. Paul Stravers is chief architect and co-founder of Vector
Fabrics. He has 24 years of experience in academics and industry
in the fields of computer architecture, design automation and
embedded system design. He holds a Ph.D. in electrical
engineering from Delft University of Technology.
Tom Dickens, Boeing Associate Technical Fellow at Boeing, Renton,
WA, USA, thomas.p.dickens@boeing.com
Tom Dickens is a Boeing Associate Technical Fellow at Boeing,
with 28 years of experience building software systems for
engineers (C, C++, Java) and designing, building, and programing
embedded systems (assembly code). He also has over 20 years
teaching at the university level. He has a BS in Electronics
Engineering from Henry Cogswell College and an MS in Computer
Engineering from NTU.
David Kleidermacher, Chief Technology Officer, Green Hills Software,
Inc., Santa Barbara, CA, USA, davek@ghs.com
David Kleidermacher is Chief Technology Officer at Green Hills
Software, where he is responsible for technology strategy, platform
planning, and solutions design. Kleidermacher has spent 21 years
working in the areas of systems software and security, including
secure operating systems, virtualization technology, and high
robustness infrastructure. Kleidermacher earned his bachelor of
science in Computer Science from Cornell University.
Gitu Jain, Software Engineer, Synopsys, gitujain@yahoo.com
Dr. Gitu Jain is a Software Engineer at Synopsys and also teaches
at the UC Santa Cruz Extension in Silicon Valley. She has 20
years of experience in software R&D at semiconductor companies,
with expertise in parallel computing and EDA algorithm design.
She has a Ph.D. in Electrical and Computer Engineering from the
University of Iowa.
Sanjay Lal, Cofounder of Kyma Systems, Danville, CA, USA,
sanjayl@kymasys.com
Sanjay Lal is cofounder of Kyma Systems, an engineering
consulting firm. He has 15 years of experience, with specific
expertise in the areas of operating systems, hypervisors, bare-metal
data-path programming, computer networks, and processor
architectures. He has a Bachelors and Masters of Applied Science
from the University of Toronto.
Sanjay R. Deshpande, Design Manager, Freescale Semiconductor,
Austin, TX, USA, R58977@freescale.com
Dr. Sanjay R. Deshpande is a Distinguished Member of the
Technical Staff and a Design Manager at Freescale Semiconductor.
He has over 30 years of experience in the areas of multicore
interconnect technology, cache coherency, and I/O virtualization.
He has a Bachelor of Technology degree from Indian Institute of
Technology, Bombay, India, and an MS in Computer Science and a
Ph.D. in Electrical and Computer Engineering, both from the
University of Texas, Austin.
Frank Schirrmeister, Senior Director, System Development Suite at
Cadence Design Systems, Santa Clara, CA, USA,
frank@schirrmeister.com
Frank Schirrmeister is Senior Director for Product Management of
the System Development Suite at Cadence Design Systems. He
has over 20 years of experience in IP and semiconductor design,
embedded software development, hardware/software co-
development and electronic design automation. He holds a MSEE
(Dipl.-Ing.) from the Technical University of Berlin, Germany.
Chapter 1
Introduction and Roadmap
Bryon Moyer, Technology Writer and Editor, EE Journal
Chapter Outline
Multicore is here
Scope
Who should read this book?
Organization and roadmap
Concurrency
Architecture
High-level architecture
Memory architecture
Interconnect
Infrastructure
Operating systems
Virtualization
Multicore-related libraries
Application software
Languages and tools
Partitioning applications
Synchronization
Hardware assistance
Hardware accelerators
Synchronization hardware
System-level considerations
Bare-metal systems
Debug
A roadmap of this book
Multicore is here
Actually, multicore has been around for many years in the desktop
and supercomputing arenas. But it has lagged in the mainstream
embedded world; it is now here for embedded as well.
Up until recently, multicore within embedded has been restricted
primarily to two fields: mobile (assuming it qualifies as an
embedded system, a categorization that not everyone agrees with)
and networking. There have been multiple computing cores in
phones for some time now. However, each processor typically
owned a particular job – baseband processing, graphics
processing, applications processing, etc. – and did that job
independently, with little or no interaction with other processing
cores. So multicore really wasn’t an issue then. That’s changed
now that application processors in smartphones have multiple
cores: it’s time to start treating them as full-on multicore systems.
Meanwhile, networking (or, more specifically, packet-processing)
systems have used multicore for a long time, well before any
tools were available to ease the multicore job. This has been a
highly specialized niche, with rockstar programmers deeply imbued
with the skills needed to extract the highest possible performance
from their code. This has meant handcrafting for specific
platforms and manual programming from scratch. This world is
likely to retain its specialty designation because, even as multicore
matures, the performance requirements of these systems require
manual care.
For the rest of embedded, multiple cores have become an
unavoidable reality. And multicore has not been enthusiastically
embraced for one simple reason: it’s hard. Or it feels hard.
There’s been a huge energy barrier to cross to feel competent in
the multicore world.
Some parts of multicore truly are hard, but as it reaches the
mainstream, many of the issues that you might have had to
resolve yourself have already been taken care of. There are now
tools and libraries and even changes to language standards that
make embedded multicore programming less of a walk in the
wild.
And that’s where this book comes in. There have been people
quietly working for years on solving and simplifying multicore
issues for embedded systems. And let’s be clear: what works for
desktops is not at all acceptable for embedded systems, with their
limitations on size, resources and power. It has taken extra work
to make some of the multicore infrastructure relevant to
embedded systems.
Some of the people involved in those processes or simply with
experience in using multicore have contributed from their vast
knowledge to help you understand multicore for embedded. Most
importantly, the intent is that, by taking in the various topics
we’ve covered, you’ll cross over that energy barrier and be able to
start doing the multicore work you need to do.
Scope
The term “embedded system” is broad and ill-defined. You
probably know it when you see it, although community standards
may vary. We won’t try to define what is included; it’s probably
easier to say what isn’t included:
general computing (although desktop computers are sometimes
harnessed for use in embedded applications)
computing (HPC), the realm of supercomputers and massively
parallel scientific and financial computing.
Many of the concepts discussed actually apply to both of those
realms, but we will restrict examples and specifics to the
embedded space, and there will be topics (like MPI, for example)
that we won’t touch on.
Who should read this book?
This book is for anyone that will need to work on embedded
multicore systems. That casts a wide net. It includes:
architects that are transitioning from single-core to multicore
systems.
architects that have to implement sophisticated systems-on-chips
(SoCs).
programmers designing infrastructure and tools to support
embedded multicore.
programmers writing multicore applications.
programmers taking sequential programs and rewriting them for
multicore.
engineers trying to debug and optimize a multicore system.
This means that we deal with hardware, firmware/middleware,
software, and tools. The one area we don’t deal with is actual
hardware circuit design. We may talk about the benefits of
hardware queuing, for example, but we won’t talk about how to
design a hardware queue on a chip.
We have assumed that you are an accomplished engineer with
respect to single-core embedded systems. So we’re not going to
go too far into the realm of the basic (although some review is
helpful for context). For example, we won’t describe how operating
systems work in general – we assume you know that. We talk
about those elements of operating systems that are specific to
multicore.
Organization and roadmap
In order to give you the broad range of information that
underpins multicore technology, we’ve divided the book into
several sections. These have been ordered in a way that allows a
linear reading from start to finish, but you can also dive into
areas of particular interest directly if you have experience in the
other areas. Each chapter is an independent “essay”, although
we’ve tried to avoid too much duplication, so you will find some
references from chapter to chapter.
Concurrency
We start with a review of the concept that underlies everything
that matters in this book: concurrency. The reason everything
changes with multicore is that our old assumption that one thing
happens before another no longer holds true. More than one
thing can happen at the same time, meaning we get more work
done more quickly, but we also open up a number of significant
challenges that we haven’t had to deal with before. Understanding
concurrency in detail is important to making sense out of
everything else that follows.
Architecture
The next section concedes the fact that hardware is expensive to
design, therefore hardware platforms will be created upon which
software will be written. It’s nice to think that embedded systems
are a perfect marriage between purpose-built hardware and
software that have been co-designed, but, in reality, especially
when designing an expensive SoC, the hardware must serve more
than just one application.
High-level architecture
This chapter takes a broad view of multicore hardware architecture
as it applies to embedded systems. Author Frank Schirrmeister
focuses on the arrangement of processing cores, but he must
necessarily include some discussion of memory and interconnect
as well. The intent of this chapter is to help you understand
either how to build a better architecture or how to select an
architecture.
Memory architecture
Memory can be arranged in numerous different ways, each of
which presents benefits and challenges. In this chapter, author
Gitu Jain picks up on the more general description in the high-
level architecture chapter and dives deeper into the implications
not only of main memory, but also of cache memory and the
various means by which multiple caches can be kept coherent.
Interconnect
Processors and memory are important, but the means by which
they intercommunicate can have a dramatic impact on
performance. It can also impact the cost of a chip to the extent
that simply over-provisioning interconnect is not an option. Sanjay
Deshpande provides a broad treatment of the considerations and
trade-offs that apply when designing or choosing an interconnect
scheme.
Infrastructure
Once the hardware is in place, a layer of services and abstraction
is needed in order to shield applications from low-level details.
This starts with something as basic and obvious as the operating
system, but includes specialized libraries supporting things like
synchronization.
Operating systems
Operating systems provide critical services and access to resources
on computing platforms. But with embedded systems, the number
of options for operating systems is far larger than it is for other
domains. Some of those options can’t deal with multicore; others
can. Some are big and feature-rich; others are small or practically
non-existent. And they each have different ways of controlling how
they operate. So in this chapter, with the assistance of Bill Lamie
and John Carbone, I discuss those elements of operating systems
that impact their performance in multicore systems, including the
ability of associated tools to assist with software-level debugging.
Virtualization
The increased need for security and robustness has made it
necessary to implement varying levels of virtualization in
embedded systems. Author David Kleidermacher describes the
many different ways in which virtualization can be implemented,
along with the benefits and drawbacks of each option.
Multicore-related libraries
The details of multicore implementation can be tedious and error-
prone to put into place. A layer of libraries and middleware can
abstract application programs away from those details, making
them not only more robust and easier to write, but also more
portable between systems that might have very different low-level
features. Author Max Domeika takes us on a tour of those
multicore-related resources that are available to help ease some of
the burden.
Application software
The goal of a good multicore system is to make the underlying
configuration details as irrelevant as possible to the application
programmer. That’s less possible for embedded systems, where
programmers work harder to optimize their software to a specific
platform. But multicore raises specific new issues that cannot be
ignored by programmers.
Languages and tools
Some languages are better than others at handling the parallelism
that multicore systems make possible. That said, some languages
are more popular than others without regard to their ability to
handle parallelism. Author Gitu Jain takes us through a variety of
languages, covering their appropriateness for multicore as well as
their prevalence.
Meanwhile, tailoring an application for a multicore platform
suggests analysis and tools that don’t apply for single-core
systems. Author Kenn Luecke surveys a range of tools from a
number of sources that are applicable to multicore design.
Partitioning applications
Since multicore systems can do more than one thing at a time,
application programs that were once sequential in nature can be
teased apart to keep multiple cores busy. But that process of
splitting up a program can be very difficult. I’m assisted by Paul
Stravers in this chapter that describes the issues surrounding
partitioning and then shows you how to do it both manually and
with new specialized tools designed to help.
Synchronization
The success of various pieces of a program running in parallel to
yield a correct result depends strongly on good synchronization
between those different pieces. This concept lies at the heart of
what can make or break a multicore application. Author Tom
Dickens runs through a litany of dos and don’ts for keeping an
application program on track as it executes.
Hardware assistance
While there may appear to be a bright line defining what is
expected in hardware and what should be in software, there are
some gray areas. In some cases, hardware can assist with specific
functions to improve performance.
Hardware accelerators
There are times when a hardware block can increase the
performance of some compute-intensive function dramatically over
what software can manage. Those accelerators can be designed to
operate in parallel with the cores, adding a new concurrency
dimension. In this chapter, Yosinori Watanabe and I discuss
hardware accelerators and their considerations for integration into
embedded multicore systems.
Synchronization hardware
Much of the bookkeeping and other details required for correct
functioning of a multicore system is handled by low-level software
services and libraries such as those described in the earlier
chapter on multicore libraries. But hardware infrastructure can help
out here as well – to the point of the processor instruction set
having an impact. So author Jim Holt takes a look at some
important low-level hardware considerations for improving
embedded system performance.
System-level considerations
We close out with system-level optimization concepts: bare-metal
systems and debugging. These chapters complement the preceding
material, leveraging all of the concepts presented in one way or
another.
Bare-metal systems
The performance of some systems – notably, the packet-processing
systems mentioned at the outset of this introduction – is so
critical that the overhead of an operating system cannot be
tolerated. This suggests a completely different way of doing
multicore design. Sanjay Lal and I describe both hardware and
software considerations in such a system.
Debug
Finally, debug can be much more difficult in a multicore system
than in a single-core one. It’s no longer enough to stop and start
a processor and look at registers and memory. You have multiple
cores, multiple clocks, multiple sets of interrupts and handlers,
and multiple memories and caches, each of which may be
marching to the beat of a different drummer. Successful debug
relies heavily on the existence of robust control and observability
features, and yet these features entail costs that must be
balanced. Author Neal Stollon discusses those trade-offs and
trends for multicore debug.
A roadmap of this book
Figure 1.1 illustrates the relationships between the various chapters
and their relationship to system design. The particular depiction of
the design process may feel oversimplified, and, in fact it is. But,
as with everything embedded, each project and process is
different, so this should be viewed as a rough abstraction for the
purposes of depicting chapter relevance.
Figure 1.1 A rough depiction of embedded multicore system
development.
Based on this model:
should read the Concurrency chapter.
architects and designers can jump into the various platform-
design-related chapters, with Architecture, Memory, and
Interconnect being the most fundamental. Hardware
synchronization is important if designing accelerated infrastructure.
those engineers adapting an OS or virtualization platform or
writing drivers or adapting libraries, there are chapters specifically
introducing those topics.
application writers, Partitioning and Synchronization are important
chapters. Hardware accelerators are also included here because
our focus is not on designing the hardware for the accelerator,
but rather on using it within the system: invoking it in software,
writing drivers for it, and handling the concurrency that it can
bring. There is also an overview of languages and tools as they
pertain to multicore to help make choices at the start of a
project.
and verification engineers can tackle the Debug chapter.
designers and programmers trying to extract maximal performance
can take on the Bare-metal chapter.
That said, everyone can benefit from the topics they’re not
specifically involved in. A hardware designer can design a better
platform if he or she understands the real-world issues that
software programmers face either when writing an application or
building firmware. A programmer writing an application can write
better code if he or she understands the nuances and trade-offs
involved in the platform that will run the code.
Our goal is to bring to you the experiences of those that have
been tackling these issues before it was mainstream to do so.
Each of their chapters encapsulates years of learning what works
and what doesn’t work so that you don’t have to repeat those
lessons. We hope that this serves you well.
Welcome to the age of embedded multicore.
Chapter 2
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"No, sir; I could not afford it."
"I shall arrange to have you take meals here with Chester, but after
eight o'clock in the evenings you will be your own master. Now as to
the matter of compensation. Will ten dollars a week satisfy you?"
"Ten dollars a week and my meals?"
"Yes."
"I didn't expect so much."
"I like to pay liberally, and expect to be well served."
"When shall I commence, sir?"
"At once. I want to take the next train for the city. As I go down
stairs I will tell them that you are to take your meals here. Now,
Chester, I will leave you with your new friend, as I have barely time
to reach the next train for New York."
CHAPTER XV.
TWO ODD ACQUAINTANCES.
"Ten dollars a week!" repeated Harry Bertram, to who Jed
communicated his good luck. "Why, that is famous!"
"Ten dollars a week and my meals!"
"Better still. That is better than acting."
"I don't know how I shall suit Mr. Holbrook."
"You will suit him if you suit the boy."
By this time Chester made his appearance.
"I want to walk on the beach," he said. "Come, Jed."
And the boy put his hand confidingly in that of Jed.
They descended the steps that led from the bluff to the beach, and
walked leisurely up and down on the sand. Presently Chester
expressed a wish to sit down, and before long was engaged with a
small wooden spade in making a sand fortification.
Relieved from duty, since his young charge could come to no harm,
Jed had leisure to watch the crowds passing him in both directions.
Presently a thin, dark-complexioned man, of perhaps thirty-five, after
walking up and down the beach, came to a stop, and, apparently
without motive, seated himself on the sand beside Chester and his
youthful guardian.
"A pleasant day," he remarked, looking at Jed.
"Yes," answered Jed politely.
He was not favorably impressed by the stranger's appearance, but
recognized the claims of courtesy.
"Is this little boy your brother?"
"No," answered Jed.
"I thought perhaps you brought him down to the beach."
"I did."
"I have seen him about before—with a girl."
"That was Clara, my old nurse," said Chester, who caught the drift of
the conversation. "I haven't got any nurse now," he added proudly.
"I saw you talking to Clara one day," he added, after a closer
examination of the stranger's features.
"Oh, no, my little boy!" said the man, seeming annoyed. "I don't
know Clara, as you call her."
"Then you look just like the man that was talking with her."
The stranger opened his mouth and smiled unpleasantly.
"I dare say there are people that look like me," he said, "though I
can't say I ever met one. What is your name, my little friend?"
"I am not your friend," said Chester, who did not appear favorably
impressed by his new acquaintance.
"My little enemy, then."
"My name is Chester Holbrook."
"And how old are you?"
"Ten years old. How old are you?"
Again the man's lips opened in an unpleasant smile.
"You have an inquiring mind, Chester," he said. "I am—thirty years
old."
"You look older than that."
"I am afraid that is not polite, Chester," said Jed gently.
"Why isn't it?" asked Chester innocently.
"People don't like to be thought older than they are."
"Oh, never mind," said the dark man. "A child is licensed to say what
he pleases. So he is your charge?"
"Yes, sir."
"I don't think I have seen you here before. Have you known Mr.
Holbrook long?"
"No." Then upon the impulse of the moment Jed inquired, "Do you
know him?"
The man's face changed, and he looked a shade embarrassed.
"Why do you think I know him?" he asked.
"I don't think it, but as you seemed interested in the boy, I asked
you the question."
"Oh, that's it. I have seen Mr. Holbrook, and I may have spoken to
him. I can't be sure on the subject, as I meet a good many people.
Are you going in bathing?"
"Do you want to bathe, Chester?" asked Jed.
"No; papa told me not to go to-day, as I have a cold."
"I thought perhaps I would have had your company in the surf. Well,
I must be going or I shall be late for the bath."
The stranger got up slowly and sauntered away.
"I don't like that man. Do you, Jed?" asked Chester.
"Not very much. I never saw him before."
"I have seen him. I saw him one day last week."
"Did you see him on the beach?"
"Yes; he came up and talked with Clara."
"But he said you were mistaken about that."
"I was not mistaken," said Chester positively. "I remember him very
well."
"Do you remember what he was talking about?" asked Jed, struck by
what the boy said.
"Yes; he was asking questions about me."
"He seems a good deal interested in you. Perhaps he is especially
fond of small boys."
Chester shook his head.
"I don't think he is," he answered.
When the bathing hour was over they ascended the steps and took
seats in a summer house on the bluff.
Ten minutes later a tall woman, with piercing black eyes and a
swarthy complexion, entered the arbor and sat down beside them.
"Do you want your fortune told?" she asked of Jed.
He shook his head.
"I don't believe in fortune-tellers," he said.
"Don't you? Let me convince you of my power. Give me your hand."
There seemed a fascination about the woman, and almost
involuntarily he suffered her to take his hand.
"You look prosperous," she began abruptly, "but your life has been
full of poverty and privation. Is this true?"
"Yes," answered Jed, impressed in spite of himself by the woman's
words.
"Shall I tell you where your early years were passed?"
"No," answered Jed, with a quick look at Chester. He did not care to
have the boy hear that his life had been passed in the Scranton
poorhouse.
"You are right. The knowledge could do no good and might
embarrass you. You admit that I have told the truth?"
"Yes."
"Then shall I tell you of the future?"
Jed did not answer, but the woman took his assent for granted and
went on. "You will be rich—some day."
"Shall I? I am glad to hear that. But I don't know where the wealth
is to come from."
"It is not necessary for you to know. It will be enough if it comes."
"I agree with you there," said Jed, smiling. "Will it be soon?"
"That is a question which I might answer, but I will not."
"I don't care to know, as long as I am to be prosperous some day.
Shall I ever go back to—to the place where my earlier years were
passed?"
"You may, but not to live. That part of your life is over."
"I am glad of that at any rate. One question more. Shall I meet my—
any one belonging to me—any one to whom I am related?"
Jed fixed his eyes anxiously upon the fortune-teller, for skeptical as
he was at first, he was beginning to have some confidence in her
claims to knowledge.
"Yes."
"When?"
"Don't seek to know more. Let me look at this boy's hand. Do you
want me to tell your fortune, my pretty?"
Chester laughed.
"Yes," he said. "Perhaps you can tell me if I will ever be a soldier. I
would like to be a General."
"No; you will never be a soldier, but you will have a fight before
you."
"A fight? What kind of a fight?"
The fortune-teller turned to Jed and said rapidly, "This boy is
threatened with a serious danger. He has an enemy."
"How can a young boy have an enemy?"
"There are few who do not have enemies," said the woman
sententiously.
"Can you describe the enemy?"
"He is a dark man, not tall, but taller than you. He is thin."
"I met such a man on the beach," said Jed, surprised. "I met him
only this morning. Is he the one you mean?"
"When you meet such a man beware of him!" said the woman, and
without waiting for a reply she rose from her seat and walked away
rapidly.
"What a funny old woman!" said Chester. "I am hungry. Let us go up
to the hotel. It is time for lunch."
Jed's face became thoughtful. What he had heard left a deep
impression upon his mind.
CHAPTER XVI.
MISS HOLBROOK, SPINSTER.
It was at first on Jed's mind to tell Mr. Holbrook of his encounter
with the young man upon the beach and his subsequent
conversation with the fortune-teller and her predictions in regard to
Chester. But he was afraid of being laughed at.
Moreover, as the days passed the impression made upon his mind
became weaker, and was only recalled when from time to time he
saw the young man on the sands or walking on the bluff.
He got on very well with Chester. The boy became strongly attached
to him, much to the satisfaction of his father.
"So you like Jed, do you?" said Mr. Holbrook one evening, on his
return from the city.
"Yes, papa, I like him ever so much."
"Do you like him as much as Clara?"
"Why, I don't like her at all."
Time wore on till the middle of August. Jed enjoyed his generous
meals and the sea bathing which he shared in company with his
young charge. He still lodged with Harry Bertram, but he shared the
expense of the room.
But a change was coming, and an unwelcome one.
"Chester," said his father one evening, "I am going away for a week
or ten days."
"Take me with you, papa!"
"No, I cannot. I am called to Chicago on business, and you will be
much better off here at the beach."
"Jed will stay with me?"
"Yes, and I have sent for your Aunt Maria to come and look after you
while I am gone."
"But I don't like Aunt Maria," objected the little boy. "She's always
scolding me. She doesn't like boys."
"Perhaps not," said Mr. Holbrook with a smile. "If Maria had married
it might have been different, but I believe few maiden ladies are
fond of children."
"Then why do you have her come here, papa? Jed can take care of
me."
"I have great confidence in Jed, Chester, but you will need some one
to look after your clothes and oversee you in other ways."
"Isn't there any one else you can send for, papa? I don't like old
maids."
"Don't trouble me with your objections, Chester. It will only be for a
little while, remember. I am sure you can get along with your aunt
for ten days."
"I will try to," answered the boy with a look of resignation.
The next day Miss Maria Holbrook came to Sea Spray with her
brother. She was a tall, slender lady of middle age, with a thin face,
and looked as if she were dissatisfied with a large proportion of her
fellow-creatures.
Chester looked at her, but did not show any disposition to welcome
her to the beach.
"You may kiss me, Chester," said the lady with an acid smile.
"Thank you, Aunt Maria, but I am not particular about it."
"Well, upon my word!" ejaculated the spinster. "My own brother's
child, too!"
"Kiss your aunt, Chester," said his father.
"No, it is not necessary," put in Miss Holbrook sharply. "I don't want
any hypocritical caresses. Robert, I am afraid you are spoiling that
boy."
"Oh, no, Maria, not quite so bad as that. Chester is a middling good
boy."
Miss Maria Holbrook sniffed incredulously.
"I am afraid you judge him too leniently," she said.
"Well, you can tell better after you have had time to observe him. It
is two years now since you have seen Chester."
"Let us hope that my first impressions may be modified," said the
spinster in a tone that indicated great doubt whether such would be
the case.
"Jed, you may go. Chester will not need you any more this evening,"
said Mr. Holbrook.
"Thank you, sir," said Jed, and walked away.
"Who is that boy?" asked the spinster abruptly, looking at him
through her eyeglasses.
"He is in charge of Chester while I am in the city."
"Why, he is only a boy!"
"Is that against him?"
"I thought Chester had a nurse."
"So he did, but she proved dishonest."
"Then why didn't you engage another?"
"Because Chester felt sensitive about having a girl following him.
The other boys in the hotel laughed at him."
"Let them laugh!" said Miss Holbrook severely. "Are you to have your
plans changed by a set of graceless boys?"
"As to that, Maria, I find this boy more satisfactory, both to Chester
and myself."
"Humph! What is his name?"
"Jed."
"A very plebeian name."
"It isn't exactly fashionable, but names are not important."
"I beg your pardon. I think names are important."
"Perhaps that is the reason you have never changed yours, Maria.
You might have been Mrs. Boggs if you had been less particular."
"I would rather remain unmarried all my life. But where did you pick
up this boy?"
"I met him in the hotel."
"Was he boarding here?"
"No; I think he was boarding somewhere in the village."
"Do you know anything of his family?"
"No."
"Do you know anything of his antecedents?" continued Miss
Holbrook.
"Yes; he played a part last season in the 'Gold King.'"
"Heavens and earth!" ejaculated the spinster, holding up her hands
in horror. "Do you mean to tell me that you have placed your son in
the charge of a young play actor?"
Mr. Holbrook laughed.
"Why not?"
"I am surprised that you should ask. You know as well as I do the
character of actors."
"I know that some of them are very estimable gentlemen. As to Jed,
he has not been long on the stage, I believe."
"Do you know anything of his family? Is he respectably connected?"
"I didn't think it important to inquire. It seems to me that the boy's
own character is much more to the point. I have found Jed faithful
and reliable, without bad habits, and I feel that Chester is safe in his
hands."
"Oh you men, you men!" exclaimed Miss Holbrook. "You don't seem
to have any judgment."
"I suppose," said Mr. Holbrook with good-natured sarcasm, "that all
the good judgment is monopolized by the old maids. What a pity
they have no children to bring up."
"Brother!" said Miss Holbrook in a freezing tone.
"I beg your pardon, Maria, but please credit me with a little good
sense."
Miss Holbrook went up to the room assigned her with an offended
expression, and had nothing further to say about Jed that evening.
The next morning Jed reported for duty just as Mr. Holbrook was
leaving for his journey.
"Look after Chester while I am gone, Jed," said Mr. Holbrook
pleasantly. "This is my sister, Miss Maria Holbrook, who will take my
place here while I am gone."
Jed took off his hat politely, and Miss Holbrook honored him with a
slight inclination of her head and a forbidding look.
"Good-by, Maria! I will telegraph you on my arrival in Chicago."
"Good-by, brother! You need have no apprehensions about Chester
while I am here."
"I shall rest quite easy. Between you and Jed I am sure he will come
to no harm."
Miss Holbrook pursed up her mouth at the conjunction of her name
with Jed's, but said nothing.
"Shall I go and take a walk with Jed?" asked Chester.
"Yes, in a moment. I wish to speak to the young man first."
"What young man?"
"Jedediah."
"Jedediah!" echoed Chester with a merry laugh. "How funny that
sounds!"
"I apprehend that Jedediah is your right name," said Miss Holbrook
severely.
"I suppose so," answered Jed.
"You suppose so?"
"I mean that I have always been called Jed. I don't remember ever
having been called by the full name."
"Don't your parents call you so?"
"My parents are not living."
"When did they die?"
Jed looked troubled.
"When I was a baby," he answered gravely.
"Indeed! Then who brought you up?"
"Mr. and Mrs. Avery."
"Were they any relations of yours?"
"No, but they were very kind to me."
"Come along, Jed! There's the steamboat just leaving the pier!"
called Chester impatiently.
Without waiting to be further questioned Jed answered the call of his
young charge. He was glad to get away, for he felt that the spinster
might ask him some questions which he would find it difficult to
answer.
CHAPTER XVII.
JED MEETS AN OLD ACQUAINTANCE.
Jed was not long in finding that Chester's aunt looked upon him, if
not with hostility, at least with distrust. This was an unpleasant
discovery. Mr. Holbrook had always appeared to have confidence in
him, and approved his management of his son.
While Chester and Jed were walking on the beach Miss Holbrook
took a seat upon the bluff and watched them through her
spectacles, as Jed could not help seeing.
"I say, Jed," asked the little boy, "how do you like Aunt Maria?"
"I don't feel very well acquainted with her yet," answered Jed
cautiously.
"I don't like her!" said Chester emphatically.
"Why not?"
"Oh, she's always scolding and finding fault. Papa says it's because
she's an old maid."
Jed smiled.
"I wish papa had not sent for her," went on Chester. "We could get
along well enough without her."
"I think we should get along very well together, Chester."
"I am sure we should. Have you got any old maid aunts?"
"Not that I know of," replied Jed soberly, as he had forced upon him
the thought of his solitary condition.
"Then you are lucky. I'll give you Aunt Maria if you want her."
"Perhaps she might not consent to be given away, Chester."
Half an hour later Jed met with a surprise, and one not altogether
agreeable.
"Hello! you here!" exclaimed an amazed voice that sounded familiar
to Jed.
He looked up and saw Percy Dixon approaching.
"Oh, it's you, Percy?" he said. "When did you arrive?"
"This morning. Father and I are staying at the Spray House." This
was the largest hotel, and Percy mentioned the name with evident
pride.
"It is a nice hotel," responded Jed.
"I should say so. Why, it's the most expensive one here. But you
haven't told me how you came here."
"I have been here for some weeks."
"Where do you live?"
"I have a room in the village, but I take my meals at the Spray
House."
"You take your meals at the Spray House?" ejaculated Percy.
"Yes."
"How can you afford it?"
"This boy's father pays my board. I look after Chester."
"What's your name?" asked Chester, who was by no means bashful.
"Percy Dixon," answered Percy politely, for he judged that Chester
belonged to a rich family.
"So you know Jed?"
"Yes. I have that honor," returned Percy with a curl of the lip. "When
did you leave off acting?" he asked, turning to Jed.
"At the end of the season. Few dramatic companies play during the
summer."
"Are you going to play with them again?"
"I don't know yet. The boy whose place I took may be ready to take
his own part in the fall."
"I saw your old friends Mr. and Mrs. Fogson just before I came
away," said Percy significantly. "Wouldn't you like to know how they
are?"
"No; I feel no particular interest in them."
"They are interested in you. Fogson says he's bound to get you back
some time."
"I don't care to talk of them," said Jed coldly.
"Are you going in bathing?" asked Chester.
"Yes, I think so. Do you go in?"
"Shall we go in, Jed?" asked the little boy.
"Yes, if you like, Chester."
The three boys repaired to the bathing-houses and prepared for
their bath.
As they walked up to the hotel together afterwards, Percy remarked:
"It seems strange to see you in such a place as this."
"I suppose so."
"It's funny how you get on. How did you get the chance to take care
of the little boy?"
Jed explained.
"Is Chester's father rich?"
"I presume so, from what I hear."
"Is he here now?"
"No; he is in Chicago for a week or ten days."
"And is there no one except you to take care of the boy?"
"There is an aunt of Chester's in the hotel—his father's sister. There
she is now!" and Jed pointed out Miss Maria Holbrook.
Percy noticed her attentively, and was observed in turn by the
spinster, who privately resolved to seek some information about Jed
from one who appeared to know him.
After dinner, while on the piazza, Miss Holbrook noticed Percy sitting
but a few feet distant.
"Ahem!" she began. "Young man, will you do me the favor to move
your chair a little nearer?"
Percy did so gladly. He wished for a chance to become acquainted
with Jed's employers.
"Thank you. May I ask your name?"
"Percy Dixon."
"I noticed that you seemed to be acquainted with the boy who is in
charge of my young nephew Chester."
"Yes, ma'am, I know him."
"Have you known him long?"
"As far back as I can remember."
"Did you live in the same town?"
"Yes, ma'am."
"Where?"
"Scranton."
"You must pardon my curiosity, but my brother—Chester's father—
engaged this boy without apparently knowing much about him,
except that he had been on the stage."
"He wasn't on the stage long."
"Perhaps not, but probably he didn't get any good from it. What is
your opinion of him. Though, as you are his friend——"
"I am not his friend!" said Percy bluntly.
"Then you haven't a high opinion of him?" said Miss Holbrook
eagerly.
"No; I never liked him."
"I don't like him myself, though I can't tell exactly why not, and I am
bound to say that Chester and his father seem infatuated with him."
"I think you are quite right, Miss Holbrook."
"I can't help thinking there is some mystery about him."
"You are right, Miss Holbrook. There is a mystery about him."
"I was sure of it," exclaimed the spinster. "What is the character of
his relations?"
"He has none that I know of."
"I believe he told me his parents were dead, and that he was
brought up by a Mr. and Mrs. Avery."
"Ho, ho!" laughed Percy.
"Why do you laugh?"
"At his being brought up by Mr. and Mrs. Avery."
"Isn't it true, then?"
"Yes; but he probably didn't tell you that Mr. and Mrs. Avery had
charge of the Scranton poorhouse."
"What!" ejaculated the spinster.
"It is as I say. Until a few weeks since Jed was an inmate of the
Scranton poorhouse."
"And this boy is actually in charge of my nephew!" exclaimed Miss
Holbrook, overwhelmed with horror.
"Yes; I was very much surprised to see Jed in such company."
"My poor brother must be quite unaware of this astounding fact!"
"No doubt, Miss Holbrook. Jed is cunning. He wouldn't be very apt to
tell your brother that he is a pauper."
"A pauper! What a horrid thought! And that boy has actually the
effrontery to push himself in among people of position. I can hardly
believe it."
"If you have any doubt about it, Miss Holbrook, just write a note to
Mr. Simeon Fogson, and ask him what he thinks of Jed Gilman."
"But I thought it was Mr. Avery who kept the poorhouse."
"He did; but when my father became Overseer of the Poor," said
Percy with conscious pride, "he removed the Averys and put in Mr.
and Mrs. Fogson, whom he considered more fit for the office. The
Averys were weak people and pampered the paupers."
"Mr. Simeon Fogson, Scranton," Miss Holbrook entered on her
tablets.
"Really, Mr. Dixon, I am very much obliged to you for the important
information you have given me, and so ought my brother to be. He
has been very careless and indiscreet in engaging a boy of unknown
antecedents, but it is fortunate that Chester has an aunt who is
keenly alive to his interests."
As she rose to go to her room to write to Mr. Fogson, Percy smiled.
"Jed Gilman will find that his goose is cooked," he said to himself.
"Won't he be astonished when the thunderbolt falls?"
CHAPTER XVIII.
MR. FOGSON RECEIVES A LETTER.
Let us go back to the Scranton poorhouse. Mr. Fogson was sawing
wood near the house. It was a task which Jed had been accustomed
to do, but in his absence it devolved upon Mr. Fogson, who was very
much disinclined to that form of labor, but still more to paying for
having it done.
He had thought of requiring Isaac Needham, one of the paupers, to
do the sawing; but the old man, who was over seventy-five, proved
physically unable to do the work, and very much against his will Mr.
Fogson found himself compelled to undertake it himself.
"Drat that Jed!" he muttered, as he stopped to mop his forehead
with his red cotton handkerchief. "It's an outrage for him to throw
his work on me. I wish I had him here this blessed minute and could
give him a taste of the strap."
At this point a neighbor's boy, Joe Coakley, entered the yard.
"Here's a letter for you, Mr. Fogson," he said. "I guess it's from a
lady."
With considerable surprise Mr. Fogson took the letter in his hand.
The envelope was square, and of fine paper, while the address was
in a lady's handwriting.
Mr. Fogson examined the postmark curiously.
"Sea Spray!" he repeated. "Why, that's a fashionable watering-place.
Who can have written me from there?"
Just then Mrs. Fogson came out from the side door.
"What letter have you there?" she asked.
"It is from a lady, Mrs. F.," answered her husband with a grin.
"What business has a lady writing to you?" demanded Mrs. Fogson
suspiciously.
"Really I don't know, as I have not read the letter."
"Give it to me!"
"No, thank you. I read my own letters."
"Mr. Fogson, if you are engaged in a private correspondence with
any lady I intend to find out all about it."
"Don't be a fool, Mrs. F.; I don't know who the writer is, and I have
never had a letter from her before."
By this time he had opened the envelope, and his face quickly
assumed an expression of interest.
"It's about Jed," he exclaimed. "I'll read it to you."
This was the letter:
My Dear Sir:
I am informed that you can give me information as to the past
history of Jedediah Gilman. Some weeks ago my brother, Robert
Holbrook, a well-known merchant of New York, engaged the
boy as a companion and personal attendant of his young son
Chester, without knowing much about him or taking the trouble
to inquire. Having seen the boy, I have doubts as to whether he
is a suitable companion for a boy in my nephew's high social
station. I learn from young Mr. Percy Dixon, of your town, that
you can give me full information as to the boy's antecedents. I
shall feel indebted to you if you will take the trouble to
communicate with me by letter.
My brother is now in Chicago, and I am in temporary charge of
my nephew. I feel that it is my duty to inquire into the character
of a boy who by his intimate association with him may, if he is
unworthy, do incalculable harm to his young and trustful nature.
Yours very truly,
Maria Holbrook,
Spray Hotel,
Sea Spray, N. J.
"Well, upon my word!" ejaculated Mrs. Fogson. "So that young villain
has wormed his way into the confidence of a rich New York
merchant!"
"Like a snake in the grass," suggested Simeon Fogson.
"Exactly. It makes me shudder to think what an impostor he is. It is
providential that Percy Dixon should find him out and show him up."
"I'll show him up!" said Fogson, nodding. "I'll just write to Miss
Holbrook, and tell her of his goin's on. I reckon he won't keep his
place long after they get my letter."
"You'd better let me write the letter, Simeon."
"No, Mrs. F., the letter was addressed to me, and I'm goin' to answer
it."
"Just as you like, Mr. Fogson, but you are well aware that you are
weak in your spelling."
"Never mind, Mrs. F., I reckon I can make myself understood."
"Just as you like, Fogson. Only make it strong enough."
"You can trust me for that."
CHAPTER XIX.
DISCHARGED.
In a front room on the second floor of the Spray Hotel sat Miss Maria
Holbrook with a letter in her hand. It was written on the cheapest
note-paper, and inclosed in a plebeian brown envelope.
Of course it will be understood that it was the epistolary effort of Mr.
Simeon Fogson.
"Just as I thought!" soliloquized the lady. "This boy seems to be a
disreputable character of the lowest antecedents, and utterly
unworthy to associate even as a servant with a member of my
family."
Here Chester entered in his usual impetuous manner.
"Oh, Aunt Maria," he cried, "I had a bully bath."
"I am shocked to hear you use such a low term as 'bully,' Chester,"
said his aunt. "No doubt you learned it of Jedediah."
"No, I didn't. Jed never uses the word. At least I never heard him."
"Will you tell Jedediah that I wish to see him at once on important
business?"
"It seems funny to hear you call him Jedediah, Aunt Maria."
"I apprehend that it is his right name; 'Jed' sounds low."
"Well, I'll tell him to come up."
When Jed made his appearance Miss Holbrook said: "You may go
below, Chester. I wish to speak to Jedediah in private."
"What's up now, I wonder?" thought Jed.
The lady turned upon him a severe look.
"Jedediah," she said, "is it true that your earlier years were spent at
the Scranton poorhouse?"
"Yes, madam," answered Jed, coloring.
"Did you apprise my brother of this fact when he engaged you?"
"No, madam. I suppose you learned it from Percy Dixon."
"I learned it from young Mr. Dixon, but I could hardly believe it. He
referred me to Mr. Simeon Fogson, of Scranton, and I have a letter
from that gentleman in my hand. You probably will not care to read
it."
"I should like very much to read it, Miss Holbrook. I should like to
know whether Mr. Fogson tells the truth."
"Here is the letter, then."
Jed read it with conflicting emotions.
Respected Madam:
I am glad to give you the informashun you ask about that
young villen Jed Gilman, who ran away from the Poor House
some weeks since after a violent assault on me, his offishul
guardeen. Words cannot tell you how much trouble I have had
with that boy.
Likewise he has been very impident to Mrs. Fogson. The reeson
is that he was too much indulged by my predicesors in offis Mr.
and Mrs. Avery. I have tried to do my dooty by the boy, but as
Squire Dixon, the Overseer will tell you my efforts has been in
vane. I am not supprised that your brother was took in by Jed
for he is the artfulest boy I ever seen. I hope for the sake of
your young nefew's welfare you will discharge him at once and
not allow him to corrup his youthful mind.
Yours respectfully,
Simeon Fogson.
"Well," said Miss Holbrook triumphantly, "that doesn't seem to
commend you very highly."
"No," answered Jed, returning the letter to the envelope. "It is such
a letter as I should expect Mr. Fogson to write."
"Why?"
"Because he is unfit for his place," answered Jed boldly. "He half
starves the poor people under his charge, treats them roughly, and
is detested by all."
"He says you are impudent and troublesome."
"I did not allow him to impose upon me."
"He says you ran away."
"I had a right to leave, as I felt able to support myself. I was
recommended to do so by Dr. Redmond, the best physician in
Scranton, who is a friend of mine."
"I have listened to your side of the story," said Miss Holbrook coldly,
"and the terms in which you speak of Mr. Fogson convince me that
his charges are correct. Of course you will not expect me to keep
you in charge of my nephew."
"Will you wait till Mr. Holbrook returns?" pleaded Jed, who felt sad at
the prospect of parting with Chester.
"No; I shall not feel justified in doing so. I will pay you up to date,
and assume the charge of Chester myself."
She drew a bill from her pocket and handed it to Jed, who took it
mechanically and left the room with a sober face. He was dismissed
from his position in disgrace, a disgrace which he felt was not
deserved.
What was he to do next?
CHAPTER XX.
JED'S POOR PROSPECTS.
Jed walked around to the office of his friend Harry Bertram.
The telegraph operator noticed at once that he looked disturbed.
"What has happened, Jed?" he asked.
"I am discharged! That is all."
"Discharged? Who discharged you?"
"Miss Holbrook."
"What is her reason? What have you done?" asked Bertram, much
surprised.
"I have done nothing, but she has discovered that I was brought up
in the Scranton poorhouse," announced Jed despondently.
"As if that made you any the worse!" ejaculated Bertram indignantly.
"It isn't to my credit, at any rate. I am ashamed of it myself."
"I don't know why you should be ashamed. You have left it, and are
now earning your own living."
"I was, but I am out of work now, and I may find it hard to get
another position."
"You can perhaps go back to the stage."
"If I can take my part in the 'Gold King' I shall be satisfied," said Jed
hopefully. "When will the season commence?"
"September 7—three weeks from next Thursday."
At that moment one of the bell boys came to the telegraph office
with a letter in his hand.
"I have a letter for you, Mr. Bertram," he said.
"Ha! This is from Mordaunt. Now we shall know."
He tore open the envelope hastily. His countenance fell, and he
handed it in silence to Jed.
This is the letter.
Dear Bertram:
Season of the Gold King opens at Jersey City on the seventh of
September. As we shall have two new actors I shall call
rehearsals for the Tuesday previous. Please report at Middleton
Agency in New York on the first.
John Mordaunt, Manager.
P. S.—Ralph Clinton has recovered from his sickness, and will be
ready to resume his part.
"That settles it!" said Jed soberly, as he handed back the letter.
"That opening is closed to me."
"I am awfully sorry, Jed," returned Bertram in a tone of sympathy.
"Perhaps if you enroll your name at the agency you can get a chance
in some other play. I will speak a good word for you, and so I am
sure will Mordaunt."
Jed shook his head.
"I don't think my chance would be very good," he said, "as I have
had so little experience. Besides, it is three weeks from now. I must
try to get work before then."
"Stay here, Jed. I will pay your expenses."
"Thank you, Mr. Bertram, but I have more than money enough for
that, and you will need all yours. It will be better for me to leave Sea
Spray, and go out in the world in search of work."
"I hate to have you go, Jed. I shall feel lonesome."
"So shall I, Mr. Bertram, but we are sure to meet again," said Jed
with forced cheerfulness.
"You must promise if things don't go well with you to write to me.
You can learn from the Clipper or any of the dramatic papers where
we are playing."
"I'll promise that, Harry," said Jed, pressing the hand of his friend.
"That's right, Jed! Don't call me Mr. Bertram again."
"I will remember."
"Don't go till to-morrow."
"No, I won't. I shall need a little time to get ready."
At this point a message came for Bertram to transmit, and Jed
walked over to the beach, feeling dull and despondent. As he
sauntered on slowly with his eyes on the sand some one called out,
"Hallo, there!"
Looking up, he met the gaze of Percy Dixon.
"Where's Chester?" asked Percy.
"In the hotel, I suppose."
"Why isn't he with you?"
"Because he is no longer under my charge," answered Jed eyeing
Percy fixedly.
"Ho, ho! you don't mean to say that you're bounced!" queried Percy,
with a look of malicious pleasure.
"That is about the size of it."
"Well, I am surprised," returned Percy cheerfully. "What have you
been up to?"
"Nothing."
"Then why are you discharged?" asked Percy with a look of innocent
wonder.
"I don't think you need ask, Percy Dixon," said Jed coldly. "If you
had not made your appearance at Sea Spray I should have kept my
place."
"Ho, ho! What have I been doing, I should like to know?" asked
Percy smiling.
"I don't need to tell you. You told Miss Holbrook that I had been
brought up in the Scranton poorhouse."
"Well, it's true, isn't it?"
"Yes, it is true, but you understood very well what would be the
result of your communication."
"As she asked me about you, I had to tell."
"You gave her the name of Mr. Fogson, and led to her writing to
him."
"So he's written, has he."
"Yes; Miss Holbrook showed me the letter this morning."
"What did he say?" asked Percy, smiling.
"Probably Miss Holbrook will show you the letter if you ask her."
"I will. I should like to see what old Fogson says. He don't admire
you very much."
"There is no love lost between us."
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  • 5. Real World Multicore Embedded Systems 1st Edition Bryon Moyer Digital Instant Download Author(s): Bryon Moyer ISBN(s): 9780124160187, 0124160182 Edition: 1 File Details: PDF, 10.19 MB Year: 2013 Language: english
  • 7. Real World Multicore Embedded Systems A Practical Approach, Expert Guide Bryon Moyer
  • 8. Table of Contents Cover image Title page Copyright About the Editor About the Authors Chapter 1. Introduction and Roadmap Multicore is here Scope Who should read this book? Organization and roadmap A roadmap of this book
  • 9. Chapter 2. The Promise and Challenges of Concurrency Concurrency fundamentals Two kinds of concurrency Dependencies Loops and dependencies Shared resources Summary Chapter 3. Multicore Architectures The need for multicore architectures Multicore architecture drivers Traditional sequential software paradigms break Scope of multicore hardware architectures Basic multicore hardware architecture overview
  • 10. Specific multicore architecture characteristics Processing architectures ALU processing architectures Lightweight processing architectures Mediumweight processing architectures Heavyweight processing architectures Communication architectures Memory architectures Application specificity Application-specific platform topologies Integration of multicore systems, MPSoCs and sub-systems Programming challenges Application characteristics
  • 11. MPSoC analysis, debug and verification Shortcomings and solutions MPSoC parallel programming Parallel software and MPSoCs Summary References Chapter 4. Memory Models for Embedded Multicore Architecture Introduction Memory types Memory architecture Memory structure of multicore architecture Cache coherency Transactional memory
  • 12. Summary References Chapter 5. Design Considerations for Multicore SoC Interconnections Introduction Communication activity in multicore SoCs Functional requirements and topologies of SoC traffic Performance considerations Interconnection networks: representation and terminology Bus as an SoC interconnection Fabric-oriented interconnects for larger SoCs Building blocks of scalable interconnections Evaluating and comparing interconnection topologies for future SoCs
  • 13. A survey of interconnection networks suitable for future SoCs Some practical considerations in designing interconnections Summary References Further reading Chapter 6. Operating Systems in Multicore Platforms Introduction Symmetric multiprocessing systems and scheduling Assymetric multiprocessor systems Virtualization Controlling OS behavior Debugging a multicore system Summary Reference
  • 14. Chapter 7. System Virtualization in Multicore Systems What is virtualization? A brief retrospective Applications of system virtualization Hypervisor architectures Leveraging hardware assists for virtualization Hypervisor robustness I/O Virtualization Case study: power architecture virtualization and the freescale P4080 Example use cases for system virtualization Conclusion References Chapter 8. Communication and Synchronization Libraries
  • 15. Introduction Library overview and basics Explicit threading libraries OpenMP Threading Building Blocks Boost Threads MCAPI Conclusion References Chapter 9. Programming Languages Programming languages for multicore embedded systems C Assembly language
  • 16. C++ Java Python Ada Summary References Chapter 10. Tools Introduction Real-Time operating systems (RTOS) Communication tools Parallelizing serial software tools Software development and debug tools Benchmarking tools
  • 17. Conclusion Acknowledgments Chapter 11. Partitioning Programs for Multicore Systems Introduction What level of parallelism? The basic cost of partitioning A high-level partitioning algorithm The central role of dependencies Critical sections Synchronizing data Implementing a partitioning strategy Using tools to simplify partitioning Summary
  • 18. References Chapter 12. Software Synchronization Introduction Why is synchronization required? Problems with not synchronizing (or synchronizing badly) Testing for proper synchronization How is synchronization achieved? Specific conditions requiring synchronization Language support for implementation Patterns Side-effects of synchronization Hardware and OS effects on synchronization Problems when trying to implement synchronization
  • 19. References Chapter 13. Hardware Accelerators Introduction Architectural considerations The interface: registers, drivers, APIs, and ISRs Initialization Operating system considerations Coherency Making the architectural decisions Video example Summary Chapter 14. Multicore Synchronization Hardware Chapter overview
  • 20. Instruction set support for synchronization Hardware support for synchronization Hardware support for lock-free programming Memory subsystem considerations Conclusions References Chapter 15. Bare-Metal Systems Introduction Architectural arrangements Software architecture Building the executable image(s) Example: IPv4 forwarding Conclusion
  • 21. Reference Chapter 16. Multicore Debug Introduction – why debug instrumentation Background – silicon debug and capabilities Trace methods for multicore debug analysis Debug flows and subsystems Commercial approaches The future of multicore debug References Further reading Index
  • 22. Copyright Newnes is an imprint of Elsevier The Boulevard, Langford Lane, Kidlington, Oxford, OX5 1GB, UK 225 Wyman Street, Waltham, MA 02451, USA First published 2013 Copyright © 2013 Elsevier Inc. All rights reserved No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangement with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein).
  • 23. Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the Library of Congress
  • 24. ISBN: 978-0-12-416018-7 For information on all Newnes publications visit our web site at books.elsevier.com Typeset by MPS Limited, Chennai, India www.adi-mps.com Printed and bound in United States of America 13 14 15 16 17 10 9 8 7 6 5 4 3 2 1
  • 25. About the Editor Bryon Moyer, Technology Writer and Editor, EE Journal, bryon@moyerwriting.com Bryon Moyer is a technology writer and an editor/writer for EE Journal. He has over 30 years’ experience as an engineer and marketer in Silicon Valley, having worked for MMI, AMD, Cypress, Altera, Actel, Teja Technologies, and Vector Fabrics. He has focused on PLDs/FPGAs, EDA, embedded systems, multicore processing, networking protocols, and software analysis. He has a BSEE from UC Berkeley and an MSEE from Santa Clara University.
  • 26. About the Authors Jim Holt, Systems Architect for Freescale’s Networking and Multimedia group, Austin, TX, USA, RWBL70@freescale.com Dr. Jim Holt is a Systems Architect for Freescale’s Networking and Multimedia group, and is also a Research Affiliate at the Massachusetts Institute of Technology where he is investigating self-aware 1000-core chips of the future. He has 29 years of industry experience focused on microprocessors, multicore systems, software engineering, distributed systems, design verification, and design optimization. He earned a Ph.D. in Electrical and Computer Engineering from the University of Texas at Austin, and an MS in Computer Science from Texas State University-San Marcos. John Carbone jcarbone@expresslogic.com John A. Carbone, vice president of marketing for Express Logic, has 35 years experience in real-time computer systems and software, ranging from embedded system developer and FAE to vice president of sales and marketing. Mr. Carbone’s experience includes embedded computers, array processors, attached processors, development tools, and both commercial and proprietary real-time operating systems. Mr. Carbone has a BA degree in mathematics from Boston College.
  • 27. William Lamie blamie@expresslogic.com William E. Lamie is co-founder and CEO of Express Logic, Inc., and is the author of the ThreadX® RTOS. Prior to founding Express Logic, Mr. Lamie was the author of the Nucleus™ RTOS and co-founder of Accelerated Technology, Inc. Mr. Lamie has over 25 years’ experience in embedded systems development, over 20 of which are in the development of real-time operating systems for embedded applications. He has a BS in Computer Science from San Diego State University. Max Domeika, Technical Project Manager, Intel Corporation, Intel Corporation, Hillsboro, OR, USA, max.j.domeika@intel.com Max Domeika is a technical product manager at Intel Corporation working on HTML5. Over the past 16 years, Max has held several positions in compiler and software tools development. Max earned a BS in Computer Science from the University of Puget Sound, an MS in Computer Science from Clemson University, and a MS in Management in Science & Technology from Oregon Graduate Institute. Max is the author of Software Development for Embedded Multi-core Systems from Elsevier and Break Away with Intel® AtomTM Processors from Intel Press. Kenn Luecke kenn.r.luecke@boeing.com Kenn Luecke currently works in Boeing Test & Evaluation in the Vehicle Management Subsystem Labs. He has 23 years of experience in network systems, avionics system, multicore and
  • 28. parallel embedded software development, mission-critical computing, and security. He has a Bachelor’s degree in Computer Science from the University of Missouri-St. Louis and a Masters of Business Administration from Washington University in St. Louis. Neal Stollon, Principal Engineer with HDL Dynamics, Dallas, TX, USA, neals@hdldynamics.com Dr. Neal Stollon is Principal Engineer with HDL Dynamics, which provides on-chip digital IP consulting, integration, and analysis services for SoC design. Dr. Stollon is chairman of the Nexus 5001 Forum, a consortium developing standards based on-chip instrument solutions, and is also co-chair of the OCP-IP Debug Working Group, which also addresses SoC debug requirements. Dr. Stollon has a Ph.D in EE from Southern Methodist University and is author of the book “On-Chip Instrumentation”. Yosinori Watanabe, Senior Architect, Cadence Design Systems, Berkeley, CA, USA, watanabe@cadence.com Dr. Yosinori Watanabe is a Senior Architect at Cadence Design Systems. He has 21 years of experience in microprocessor design, embedded system design, logic and behavioral synthesis, and the design and verification of embedded systems and software. He has a Ph.D. in Electrical Engineering and Computer Sciences from the University of California at Berkeley. Paul Stravers, Chief Architect and Co-founder of Vector Fabrics
  • 29. Dr. Paul Stravers is chief architect and co-founder of Vector Fabrics. He has 24 years of experience in academics and industry in the fields of computer architecture, design automation and embedded system design. He holds a Ph.D. in electrical engineering from Delft University of Technology. Tom Dickens, Boeing Associate Technical Fellow at Boeing, Renton, WA, USA, thomas.p.dickens@boeing.com Tom Dickens is a Boeing Associate Technical Fellow at Boeing, with 28 years of experience building software systems for engineers (C, C++, Java) and designing, building, and programing embedded systems (assembly code). He also has over 20 years teaching at the university level. He has a BS in Electronics Engineering from Henry Cogswell College and an MS in Computer Engineering from NTU. David Kleidermacher, Chief Technology Officer, Green Hills Software, Inc., Santa Barbara, CA, USA, davek@ghs.com David Kleidermacher is Chief Technology Officer at Green Hills Software, where he is responsible for technology strategy, platform planning, and solutions design. Kleidermacher has spent 21 years working in the areas of systems software and security, including secure operating systems, virtualization technology, and high robustness infrastructure. Kleidermacher earned his bachelor of science in Computer Science from Cornell University. Gitu Jain, Software Engineer, Synopsys, gitujain@yahoo.com
  • 30. Dr. Gitu Jain is a Software Engineer at Synopsys and also teaches at the UC Santa Cruz Extension in Silicon Valley. She has 20 years of experience in software R&D at semiconductor companies, with expertise in parallel computing and EDA algorithm design. She has a Ph.D. in Electrical and Computer Engineering from the University of Iowa. Sanjay Lal, Cofounder of Kyma Systems, Danville, CA, USA, sanjayl@kymasys.com Sanjay Lal is cofounder of Kyma Systems, an engineering consulting firm. He has 15 years of experience, with specific expertise in the areas of operating systems, hypervisors, bare-metal data-path programming, computer networks, and processor architectures. He has a Bachelors and Masters of Applied Science from the University of Toronto. Sanjay R. Deshpande, Design Manager, Freescale Semiconductor, Austin, TX, USA, R58977@freescale.com Dr. Sanjay R. Deshpande is a Distinguished Member of the Technical Staff and a Design Manager at Freescale Semiconductor. He has over 30 years of experience in the areas of multicore interconnect technology, cache coherency, and I/O virtualization. He has a Bachelor of Technology degree from Indian Institute of Technology, Bombay, India, and an MS in Computer Science and a Ph.D. in Electrical and Computer Engineering, both from the University of Texas, Austin.
  • 31. Frank Schirrmeister, Senior Director, System Development Suite at Cadence Design Systems, Santa Clara, CA, USA, frank@schirrmeister.com Frank Schirrmeister is Senior Director for Product Management of the System Development Suite at Cadence Design Systems. He has over 20 years of experience in IP and semiconductor design, embedded software development, hardware/software co- development and electronic design automation. He holds a MSEE (Dipl.-Ing.) from the Technical University of Berlin, Germany.
  • 33. Introduction and Roadmap Bryon Moyer, Technology Writer and Editor, EE Journal Chapter Outline Multicore is here Scope Who should read this book? Organization and roadmap Concurrency Architecture High-level architecture Memory architecture Interconnect Infrastructure Operating systems Virtualization Multicore-related libraries
  • 34. Application software Languages and tools Partitioning applications Synchronization Hardware assistance Hardware accelerators Synchronization hardware System-level considerations Bare-metal systems Debug A roadmap of this book
  • 35. Multicore is here Actually, multicore has been around for many years in the desktop and supercomputing arenas. But it has lagged in the mainstream embedded world; it is now here for embedded as well. Up until recently, multicore within embedded has been restricted primarily to two fields: mobile (assuming it qualifies as an embedded system, a categorization that not everyone agrees with) and networking. There have been multiple computing cores in phones for some time now. However, each processor typically owned a particular job – baseband processing, graphics processing, applications processing, etc. – and did that job independently, with little or no interaction with other processing cores. So multicore really wasn’t an issue then. That’s changed now that application processors in smartphones have multiple cores: it’s time to start treating them as full-on multicore systems. Meanwhile, networking (or, more specifically, packet-processing) systems have used multicore for a long time, well before any tools were available to ease the multicore job. This has been a highly specialized niche, with rockstar programmers deeply imbued with the skills needed to extract the highest possible performance from their code. This has meant handcrafting for specific platforms and manual programming from scratch. This world is likely to retain its specialty designation because, even as multicore matures, the performance requirements of these systems require manual care.
  • 36. For the rest of embedded, multiple cores have become an unavoidable reality. And multicore has not been enthusiastically embraced for one simple reason: it’s hard. Or it feels hard. There’s been a huge energy barrier to cross to feel competent in the multicore world. Some parts of multicore truly are hard, but as it reaches the mainstream, many of the issues that you might have had to resolve yourself have already been taken care of. There are now tools and libraries and even changes to language standards that make embedded multicore programming less of a walk in the wild. And that’s where this book comes in. There have been people quietly working for years on solving and simplifying multicore issues for embedded systems. And let’s be clear: what works for desktops is not at all acceptable for embedded systems, with their limitations on size, resources and power. It has taken extra work to make some of the multicore infrastructure relevant to embedded systems. Some of the people involved in those processes or simply with experience in using multicore have contributed from their vast knowledge to help you understand multicore for embedded. Most importantly, the intent is that, by taking in the various topics we’ve covered, you’ll cross over that energy barrier and be able to start doing the multicore work you need to do.
  • 37. Scope The term “embedded system” is broad and ill-defined. You probably know it when you see it, although community standards may vary. We won’t try to define what is included; it’s probably easier to say what isn’t included: general computing (although desktop computers are sometimes harnessed for use in embedded applications) computing (HPC), the realm of supercomputers and massively parallel scientific and financial computing. Many of the concepts discussed actually apply to both of those realms, but we will restrict examples and specifics to the embedded space, and there will be topics (like MPI, for example) that we won’t touch on.
  • 38. Who should read this book? This book is for anyone that will need to work on embedded multicore systems. That casts a wide net. It includes: architects that are transitioning from single-core to multicore systems. architects that have to implement sophisticated systems-on-chips (SoCs). programmers designing infrastructure and tools to support embedded multicore. programmers writing multicore applications. programmers taking sequential programs and rewriting them for multicore. engineers trying to debug and optimize a multicore system. This means that we deal with hardware, firmware/middleware, software, and tools. The one area we don’t deal with is actual hardware circuit design. We may talk about the benefits of hardware queuing, for example, but we won’t talk about how to design a hardware queue on a chip.
  • 39. We have assumed that you are an accomplished engineer with respect to single-core embedded systems. So we’re not going to go too far into the realm of the basic (although some review is helpful for context). For example, we won’t describe how operating systems work in general – we assume you know that. We talk about those elements of operating systems that are specific to multicore.
  • 40. Organization and roadmap In order to give you the broad range of information that underpins multicore technology, we’ve divided the book into several sections. These have been ordered in a way that allows a linear reading from start to finish, but you can also dive into areas of particular interest directly if you have experience in the other areas. Each chapter is an independent “essay”, although we’ve tried to avoid too much duplication, so you will find some references from chapter to chapter. Concurrency We start with a review of the concept that underlies everything that matters in this book: concurrency. The reason everything changes with multicore is that our old assumption that one thing happens before another no longer holds true. More than one thing can happen at the same time, meaning we get more work done more quickly, but we also open up a number of significant challenges that we haven’t had to deal with before. Understanding concurrency in detail is important to making sense out of everything else that follows. Architecture The next section concedes the fact that hardware is expensive to design, therefore hardware platforms will be created upon which
  • 41. software will be written. It’s nice to think that embedded systems are a perfect marriage between purpose-built hardware and software that have been co-designed, but, in reality, especially when designing an expensive SoC, the hardware must serve more than just one application. High-level architecture This chapter takes a broad view of multicore hardware architecture as it applies to embedded systems. Author Frank Schirrmeister focuses on the arrangement of processing cores, but he must necessarily include some discussion of memory and interconnect as well. The intent of this chapter is to help you understand either how to build a better architecture or how to select an architecture. Memory architecture Memory can be arranged in numerous different ways, each of which presents benefits and challenges. In this chapter, author Gitu Jain picks up on the more general description in the high- level architecture chapter and dives deeper into the implications not only of main memory, but also of cache memory and the various means by which multiple caches can be kept coherent. Interconnect Processors and memory are important, but the means by which they intercommunicate can have a dramatic impact on
  • 42. performance. It can also impact the cost of a chip to the extent that simply over-provisioning interconnect is not an option. Sanjay Deshpande provides a broad treatment of the considerations and trade-offs that apply when designing or choosing an interconnect scheme. Infrastructure Once the hardware is in place, a layer of services and abstraction is needed in order to shield applications from low-level details. This starts with something as basic and obvious as the operating system, but includes specialized libraries supporting things like synchronization. Operating systems Operating systems provide critical services and access to resources on computing platforms. But with embedded systems, the number of options for operating systems is far larger than it is for other domains. Some of those options can’t deal with multicore; others can. Some are big and feature-rich; others are small or practically non-existent. And they each have different ways of controlling how they operate. So in this chapter, with the assistance of Bill Lamie and John Carbone, I discuss those elements of operating systems that impact their performance in multicore systems, including the ability of associated tools to assist with software-level debugging. Virtualization
  • 43. The increased need for security and robustness has made it necessary to implement varying levels of virtualization in embedded systems. Author David Kleidermacher describes the many different ways in which virtualization can be implemented, along with the benefits and drawbacks of each option. Multicore-related libraries The details of multicore implementation can be tedious and error- prone to put into place. A layer of libraries and middleware can abstract application programs away from those details, making them not only more robust and easier to write, but also more portable between systems that might have very different low-level features. Author Max Domeika takes us on a tour of those multicore-related resources that are available to help ease some of the burden. Application software The goal of a good multicore system is to make the underlying configuration details as irrelevant as possible to the application programmer. That’s less possible for embedded systems, where programmers work harder to optimize their software to a specific platform. But multicore raises specific new issues that cannot be ignored by programmers. Languages and tools
  • 44. Some languages are better than others at handling the parallelism that multicore systems make possible. That said, some languages are more popular than others without regard to their ability to handle parallelism. Author Gitu Jain takes us through a variety of languages, covering their appropriateness for multicore as well as their prevalence. Meanwhile, tailoring an application for a multicore platform suggests analysis and tools that don’t apply for single-core systems. Author Kenn Luecke surveys a range of tools from a number of sources that are applicable to multicore design. Partitioning applications Since multicore systems can do more than one thing at a time, application programs that were once sequential in nature can be teased apart to keep multiple cores busy. But that process of splitting up a program can be very difficult. I’m assisted by Paul Stravers in this chapter that describes the issues surrounding partitioning and then shows you how to do it both manually and with new specialized tools designed to help. Synchronization The success of various pieces of a program running in parallel to yield a correct result depends strongly on good synchronization between those different pieces. This concept lies at the heart of what can make or break a multicore application. Author Tom Dickens runs through a litany of dos and don’ts for keeping an application program on track as it executes.
  • 45. Hardware assistance While there may appear to be a bright line defining what is expected in hardware and what should be in software, there are some gray areas. In some cases, hardware can assist with specific functions to improve performance. Hardware accelerators There are times when a hardware block can increase the performance of some compute-intensive function dramatically over what software can manage. Those accelerators can be designed to operate in parallel with the cores, adding a new concurrency dimension. In this chapter, Yosinori Watanabe and I discuss hardware accelerators and their considerations for integration into embedded multicore systems. Synchronization hardware Much of the bookkeeping and other details required for correct functioning of a multicore system is handled by low-level software services and libraries such as those described in the earlier chapter on multicore libraries. But hardware infrastructure can help out here as well – to the point of the processor instruction set having an impact. So author Jim Holt takes a look at some important low-level hardware considerations for improving embedded system performance.
  • 46. System-level considerations We close out with system-level optimization concepts: bare-metal systems and debugging. These chapters complement the preceding material, leveraging all of the concepts presented in one way or another. Bare-metal systems The performance of some systems – notably, the packet-processing systems mentioned at the outset of this introduction – is so critical that the overhead of an operating system cannot be tolerated. This suggests a completely different way of doing multicore design. Sanjay Lal and I describe both hardware and software considerations in such a system. Debug Finally, debug can be much more difficult in a multicore system than in a single-core one. It’s no longer enough to stop and start a processor and look at registers and memory. You have multiple cores, multiple clocks, multiple sets of interrupts and handlers, and multiple memories and caches, each of which may be marching to the beat of a different drummer. Successful debug relies heavily on the existence of robust control and observability features, and yet these features entail costs that must be balanced. Author Neal Stollon discusses those trade-offs and trends for multicore debug.
  • 47. A roadmap of this book Figure 1.1 illustrates the relationships between the various chapters and their relationship to system design. The particular depiction of the design process may feel oversimplified, and, in fact it is. But, as with everything embedded, each project and process is different, so this should be viewed as a rough abstraction for the purposes of depicting chapter relevance. Figure 1.1 A rough depiction of embedded multicore system development. Based on this model: should read the Concurrency chapter.
  • 48. architects and designers can jump into the various platform- design-related chapters, with Architecture, Memory, and Interconnect being the most fundamental. Hardware synchronization is important if designing accelerated infrastructure. those engineers adapting an OS or virtualization platform or writing drivers or adapting libraries, there are chapters specifically introducing those topics. application writers, Partitioning and Synchronization are important chapters. Hardware accelerators are also included here because our focus is not on designing the hardware for the accelerator, but rather on using it within the system: invoking it in software, writing drivers for it, and handling the concurrency that it can bring. There is also an overview of languages and tools as they pertain to multicore to help make choices at the start of a project. and verification engineers can tackle the Debug chapter. designers and programmers trying to extract maximal performance can take on the Bare-metal chapter. That said, everyone can benefit from the topics they’re not specifically involved in. A hardware designer can design a better platform if he or she understands the real-world issues that software programmers face either when writing an application or building firmware. A programmer writing an application can write
  • 49. better code if he or she understands the nuances and trade-offs involved in the platform that will run the code. Our goal is to bring to you the experiences of those that have been tackling these issues before it was mainstream to do so. Each of their chapters encapsulates years of learning what works and what doesn’t work so that you don’t have to repeat those lessons. We hope that this serves you well. Welcome to the age of embedded multicore.
  • 51. Another Random Scribd Document with Unrelated Content
  • 52. "No, sir; I could not afford it." "I shall arrange to have you take meals here with Chester, but after eight o'clock in the evenings you will be your own master. Now as to the matter of compensation. Will ten dollars a week satisfy you?" "Ten dollars a week and my meals?" "Yes." "I didn't expect so much." "I like to pay liberally, and expect to be well served." "When shall I commence, sir?" "At once. I want to take the next train for the city. As I go down stairs I will tell them that you are to take your meals here. Now, Chester, I will leave you with your new friend, as I have barely time to reach the next train for New York."
  • 53. CHAPTER XV. TWO ODD ACQUAINTANCES. "Ten dollars a week!" repeated Harry Bertram, to who Jed communicated his good luck. "Why, that is famous!" "Ten dollars a week and my meals!" "Better still. That is better than acting." "I don't know how I shall suit Mr. Holbrook." "You will suit him if you suit the boy." By this time Chester made his appearance. "I want to walk on the beach," he said. "Come, Jed." And the boy put his hand confidingly in that of Jed. They descended the steps that led from the bluff to the beach, and walked leisurely up and down on the sand. Presently Chester expressed a wish to sit down, and before long was engaged with a small wooden spade in making a sand fortification. Relieved from duty, since his young charge could come to no harm, Jed had leisure to watch the crowds passing him in both directions. Presently a thin, dark-complexioned man, of perhaps thirty-five, after walking up and down the beach, came to a stop, and, apparently without motive, seated himself on the sand beside Chester and his youthful guardian. "A pleasant day," he remarked, looking at Jed. "Yes," answered Jed politely.
  • 54. He was not favorably impressed by the stranger's appearance, but recognized the claims of courtesy. "Is this little boy your brother?" "No," answered Jed. "I thought perhaps you brought him down to the beach." "I did." "I have seen him about before—with a girl." "That was Clara, my old nurse," said Chester, who caught the drift of the conversation. "I haven't got any nurse now," he added proudly. "I saw you talking to Clara one day," he added, after a closer examination of the stranger's features. "Oh, no, my little boy!" said the man, seeming annoyed. "I don't know Clara, as you call her." "Then you look just like the man that was talking with her." The stranger opened his mouth and smiled unpleasantly. "I dare say there are people that look like me," he said, "though I can't say I ever met one. What is your name, my little friend?" "I am not your friend," said Chester, who did not appear favorably impressed by his new acquaintance. "My little enemy, then." "My name is Chester Holbrook." "And how old are you?" "Ten years old. How old are you?" Again the man's lips opened in an unpleasant smile.
  • 55. "You have an inquiring mind, Chester," he said. "I am—thirty years old." "You look older than that." "I am afraid that is not polite, Chester," said Jed gently. "Why isn't it?" asked Chester innocently. "People don't like to be thought older than they are." "Oh, never mind," said the dark man. "A child is licensed to say what he pleases. So he is your charge?" "Yes, sir." "I don't think I have seen you here before. Have you known Mr. Holbrook long?" "No." Then upon the impulse of the moment Jed inquired, "Do you know him?" The man's face changed, and he looked a shade embarrassed. "Why do you think I know him?" he asked. "I don't think it, but as you seemed interested in the boy, I asked you the question." "Oh, that's it. I have seen Mr. Holbrook, and I may have spoken to him. I can't be sure on the subject, as I meet a good many people. Are you going in bathing?" "Do you want to bathe, Chester?" asked Jed. "No; papa told me not to go to-day, as I have a cold." "I thought perhaps I would have had your company in the surf. Well, I must be going or I shall be late for the bath." The stranger got up slowly and sauntered away.
  • 56. "I don't like that man. Do you, Jed?" asked Chester. "Not very much. I never saw him before." "I have seen him. I saw him one day last week." "Did you see him on the beach?" "Yes; he came up and talked with Clara." "But he said you were mistaken about that." "I was not mistaken," said Chester positively. "I remember him very well." "Do you remember what he was talking about?" asked Jed, struck by what the boy said. "Yes; he was asking questions about me." "He seems a good deal interested in you. Perhaps he is especially fond of small boys." Chester shook his head. "I don't think he is," he answered. When the bathing hour was over they ascended the steps and took seats in a summer house on the bluff. Ten minutes later a tall woman, with piercing black eyes and a swarthy complexion, entered the arbor and sat down beside them. "Do you want your fortune told?" she asked of Jed. He shook his head. "I don't believe in fortune-tellers," he said. "Don't you? Let me convince you of my power. Give me your hand."
  • 57. There seemed a fascination about the woman, and almost involuntarily he suffered her to take his hand. "You look prosperous," she began abruptly, "but your life has been full of poverty and privation. Is this true?" "Yes," answered Jed, impressed in spite of himself by the woman's words. "Shall I tell you where your early years were passed?" "No," answered Jed, with a quick look at Chester. He did not care to have the boy hear that his life had been passed in the Scranton poorhouse. "You are right. The knowledge could do no good and might embarrass you. You admit that I have told the truth?" "Yes." "Then shall I tell you of the future?" Jed did not answer, but the woman took his assent for granted and went on. "You will be rich—some day." "Shall I? I am glad to hear that. But I don't know where the wealth is to come from." "It is not necessary for you to know. It will be enough if it comes." "I agree with you there," said Jed, smiling. "Will it be soon?" "That is a question which I might answer, but I will not." "I don't care to know, as long as I am to be prosperous some day. Shall I ever go back to—to the place where my earlier years were passed?" "You may, but not to live. That part of your life is over."
  • 58. "I am glad of that at any rate. One question more. Shall I meet my— any one belonging to me—any one to whom I am related?" Jed fixed his eyes anxiously upon the fortune-teller, for skeptical as he was at first, he was beginning to have some confidence in her claims to knowledge. "Yes." "When?" "Don't seek to know more. Let me look at this boy's hand. Do you want me to tell your fortune, my pretty?" Chester laughed. "Yes," he said. "Perhaps you can tell me if I will ever be a soldier. I would like to be a General." "No; you will never be a soldier, but you will have a fight before you." "A fight? What kind of a fight?" The fortune-teller turned to Jed and said rapidly, "This boy is threatened with a serious danger. He has an enemy." "How can a young boy have an enemy?" "There are few who do not have enemies," said the woman sententiously. "Can you describe the enemy?" "He is a dark man, not tall, but taller than you. He is thin." "I met such a man on the beach," said Jed, surprised. "I met him only this morning. Is he the one you mean?" "When you meet such a man beware of him!" said the woman, and without waiting for a reply she rose from her seat and walked away
  • 59. rapidly. "What a funny old woman!" said Chester. "I am hungry. Let us go up to the hotel. It is time for lunch." Jed's face became thoughtful. What he had heard left a deep impression upon his mind.
  • 60. CHAPTER XVI. MISS HOLBROOK, SPINSTER. It was at first on Jed's mind to tell Mr. Holbrook of his encounter with the young man upon the beach and his subsequent conversation with the fortune-teller and her predictions in regard to Chester. But he was afraid of being laughed at. Moreover, as the days passed the impression made upon his mind became weaker, and was only recalled when from time to time he saw the young man on the sands or walking on the bluff. He got on very well with Chester. The boy became strongly attached to him, much to the satisfaction of his father. "So you like Jed, do you?" said Mr. Holbrook one evening, on his return from the city. "Yes, papa, I like him ever so much." "Do you like him as much as Clara?" "Why, I don't like her at all." Time wore on till the middle of August. Jed enjoyed his generous meals and the sea bathing which he shared in company with his young charge. He still lodged with Harry Bertram, but he shared the expense of the room. But a change was coming, and an unwelcome one. "Chester," said his father one evening, "I am going away for a week or ten days." "Take me with you, papa!"
  • 61. "No, I cannot. I am called to Chicago on business, and you will be much better off here at the beach." "Jed will stay with me?" "Yes, and I have sent for your Aunt Maria to come and look after you while I am gone." "But I don't like Aunt Maria," objected the little boy. "She's always scolding me. She doesn't like boys." "Perhaps not," said Mr. Holbrook with a smile. "If Maria had married it might have been different, but I believe few maiden ladies are fond of children." "Then why do you have her come here, papa? Jed can take care of me." "I have great confidence in Jed, Chester, but you will need some one to look after your clothes and oversee you in other ways." "Isn't there any one else you can send for, papa? I don't like old maids." "Don't trouble me with your objections, Chester. It will only be for a little while, remember. I am sure you can get along with your aunt for ten days." "I will try to," answered the boy with a look of resignation. The next day Miss Maria Holbrook came to Sea Spray with her brother. She was a tall, slender lady of middle age, with a thin face, and looked as if she were dissatisfied with a large proportion of her fellow-creatures. Chester looked at her, but did not show any disposition to welcome her to the beach. "You may kiss me, Chester," said the lady with an acid smile.
  • 62. "Thank you, Aunt Maria, but I am not particular about it." "Well, upon my word!" ejaculated the spinster. "My own brother's child, too!" "Kiss your aunt, Chester," said his father. "No, it is not necessary," put in Miss Holbrook sharply. "I don't want any hypocritical caresses. Robert, I am afraid you are spoiling that boy." "Oh, no, Maria, not quite so bad as that. Chester is a middling good boy." Miss Maria Holbrook sniffed incredulously. "I am afraid you judge him too leniently," she said. "Well, you can tell better after you have had time to observe him. It is two years now since you have seen Chester." "Let us hope that my first impressions may be modified," said the spinster in a tone that indicated great doubt whether such would be the case. "Jed, you may go. Chester will not need you any more this evening," said Mr. Holbrook. "Thank you, sir," said Jed, and walked away. "Who is that boy?" asked the spinster abruptly, looking at him through her eyeglasses. "He is in charge of Chester while I am in the city." "Why, he is only a boy!" "Is that against him?" "I thought Chester had a nurse." "So he did, but she proved dishonest."
  • 63. "Then why didn't you engage another?" "Because Chester felt sensitive about having a girl following him. The other boys in the hotel laughed at him." "Let them laugh!" said Miss Holbrook severely. "Are you to have your plans changed by a set of graceless boys?" "As to that, Maria, I find this boy more satisfactory, both to Chester and myself." "Humph! What is his name?" "Jed." "A very plebeian name." "It isn't exactly fashionable, but names are not important." "I beg your pardon. I think names are important." "Perhaps that is the reason you have never changed yours, Maria. You might have been Mrs. Boggs if you had been less particular." "I would rather remain unmarried all my life. But where did you pick up this boy?" "I met him in the hotel." "Was he boarding here?" "No; I think he was boarding somewhere in the village." "Do you know anything of his family?" "No." "Do you know anything of his antecedents?" continued Miss Holbrook. "Yes; he played a part last season in the 'Gold King.'"
  • 64. "Heavens and earth!" ejaculated the spinster, holding up her hands in horror. "Do you mean to tell me that you have placed your son in the charge of a young play actor?" Mr. Holbrook laughed. "Why not?" "I am surprised that you should ask. You know as well as I do the character of actors." "I know that some of them are very estimable gentlemen. As to Jed, he has not been long on the stage, I believe." "Do you know anything of his family? Is he respectably connected?" "I didn't think it important to inquire. It seems to me that the boy's own character is much more to the point. I have found Jed faithful and reliable, without bad habits, and I feel that Chester is safe in his hands." "Oh you men, you men!" exclaimed Miss Holbrook. "You don't seem to have any judgment." "I suppose," said Mr. Holbrook with good-natured sarcasm, "that all the good judgment is monopolized by the old maids. What a pity they have no children to bring up." "Brother!" said Miss Holbrook in a freezing tone. "I beg your pardon, Maria, but please credit me with a little good sense." Miss Holbrook went up to the room assigned her with an offended expression, and had nothing further to say about Jed that evening. The next morning Jed reported for duty just as Mr. Holbrook was leaving for his journey.
  • 65. "Look after Chester while I am gone, Jed," said Mr. Holbrook pleasantly. "This is my sister, Miss Maria Holbrook, who will take my place here while I am gone." Jed took off his hat politely, and Miss Holbrook honored him with a slight inclination of her head and a forbidding look. "Good-by, Maria! I will telegraph you on my arrival in Chicago." "Good-by, brother! You need have no apprehensions about Chester while I am here." "I shall rest quite easy. Between you and Jed I am sure he will come to no harm." Miss Holbrook pursed up her mouth at the conjunction of her name with Jed's, but said nothing. "Shall I go and take a walk with Jed?" asked Chester. "Yes, in a moment. I wish to speak to the young man first." "What young man?" "Jedediah." "Jedediah!" echoed Chester with a merry laugh. "How funny that sounds!" "I apprehend that Jedediah is your right name," said Miss Holbrook severely. "I suppose so," answered Jed. "You suppose so?" "I mean that I have always been called Jed. I don't remember ever having been called by the full name." "Don't your parents call you so?" "My parents are not living."
  • 66. "When did they die?" Jed looked troubled. "When I was a baby," he answered gravely. "Indeed! Then who brought you up?" "Mr. and Mrs. Avery." "Were they any relations of yours?" "No, but they were very kind to me." "Come along, Jed! There's the steamboat just leaving the pier!" called Chester impatiently. Without waiting to be further questioned Jed answered the call of his young charge. He was glad to get away, for he felt that the spinster might ask him some questions which he would find it difficult to answer.
  • 67. CHAPTER XVII. JED MEETS AN OLD ACQUAINTANCE. Jed was not long in finding that Chester's aunt looked upon him, if not with hostility, at least with distrust. This was an unpleasant discovery. Mr. Holbrook had always appeared to have confidence in him, and approved his management of his son. While Chester and Jed were walking on the beach Miss Holbrook took a seat upon the bluff and watched them through her spectacles, as Jed could not help seeing. "I say, Jed," asked the little boy, "how do you like Aunt Maria?" "I don't feel very well acquainted with her yet," answered Jed cautiously. "I don't like her!" said Chester emphatically. "Why not?" "Oh, she's always scolding and finding fault. Papa says it's because she's an old maid." Jed smiled. "I wish papa had not sent for her," went on Chester. "We could get along well enough without her." "I think we should get along very well together, Chester." "I am sure we should. Have you got any old maid aunts?" "Not that I know of," replied Jed soberly, as he had forced upon him the thought of his solitary condition.
  • 68. "Then you are lucky. I'll give you Aunt Maria if you want her." "Perhaps she might not consent to be given away, Chester." Half an hour later Jed met with a surprise, and one not altogether agreeable. "Hello! you here!" exclaimed an amazed voice that sounded familiar to Jed. He looked up and saw Percy Dixon approaching. "Oh, it's you, Percy?" he said. "When did you arrive?" "This morning. Father and I are staying at the Spray House." This was the largest hotel, and Percy mentioned the name with evident pride. "It is a nice hotel," responded Jed. "I should say so. Why, it's the most expensive one here. But you haven't told me how you came here." "I have been here for some weeks." "Where do you live?" "I have a room in the village, but I take my meals at the Spray House." "You take your meals at the Spray House?" ejaculated Percy. "Yes." "How can you afford it?" "This boy's father pays my board. I look after Chester." "What's your name?" asked Chester, who was by no means bashful. "Percy Dixon," answered Percy politely, for he judged that Chester belonged to a rich family.
  • 69. "So you know Jed?" "Yes. I have that honor," returned Percy with a curl of the lip. "When did you leave off acting?" he asked, turning to Jed. "At the end of the season. Few dramatic companies play during the summer." "Are you going to play with them again?" "I don't know yet. The boy whose place I took may be ready to take his own part in the fall." "I saw your old friends Mr. and Mrs. Fogson just before I came away," said Percy significantly. "Wouldn't you like to know how they are?" "No; I feel no particular interest in them." "They are interested in you. Fogson says he's bound to get you back some time." "I don't care to talk of them," said Jed coldly. "Are you going in bathing?" asked Chester. "Yes, I think so. Do you go in?" "Shall we go in, Jed?" asked the little boy. "Yes, if you like, Chester." The three boys repaired to the bathing-houses and prepared for their bath. As they walked up to the hotel together afterwards, Percy remarked: "It seems strange to see you in such a place as this." "I suppose so." "It's funny how you get on. How did you get the chance to take care of the little boy?"
  • 70. Jed explained. "Is Chester's father rich?" "I presume so, from what I hear." "Is he here now?" "No; he is in Chicago for a week or ten days." "And is there no one except you to take care of the boy?" "There is an aunt of Chester's in the hotel—his father's sister. There she is now!" and Jed pointed out Miss Maria Holbrook. Percy noticed her attentively, and was observed in turn by the spinster, who privately resolved to seek some information about Jed from one who appeared to know him. After dinner, while on the piazza, Miss Holbrook noticed Percy sitting but a few feet distant. "Ahem!" she began. "Young man, will you do me the favor to move your chair a little nearer?" Percy did so gladly. He wished for a chance to become acquainted with Jed's employers. "Thank you. May I ask your name?" "Percy Dixon." "I noticed that you seemed to be acquainted with the boy who is in charge of my young nephew Chester." "Yes, ma'am, I know him." "Have you known him long?" "As far back as I can remember." "Did you live in the same town?"
  • 71. "Yes, ma'am." "Where?" "Scranton." "You must pardon my curiosity, but my brother—Chester's father— engaged this boy without apparently knowing much about him, except that he had been on the stage." "He wasn't on the stage long." "Perhaps not, but probably he didn't get any good from it. What is your opinion of him. Though, as you are his friend——" "I am not his friend!" said Percy bluntly. "Then you haven't a high opinion of him?" said Miss Holbrook eagerly. "No; I never liked him." "I don't like him myself, though I can't tell exactly why not, and I am bound to say that Chester and his father seem infatuated with him." "I think you are quite right, Miss Holbrook." "I can't help thinking there is some mystery about him." "You are right, Miss Holbrook. There is a mystery about him." "I was sure of it," exclaimed the spinster. "What is the character of his relations?" "He has none that I know of." "I believe he told me his parents were dead, and that he was brought up by a Mr. and Mrs. Avery." "Ho, ho!" laughed Percy. "Why do you laugh?"
  • 72. "At his being brought up by Mr. and Mrs. Avery." "Isn't it true, then?" "Yes; but he probably didn't tell you that Mr. and Mrs. Avery had charge of the Scranton poorhouse." "What!" ejaculated the spinster. "It is as I say. Until a few weeks since Jed was an inmate of the Scranton poorhouse." "And this boy is actually in charge of my nephew!" exclaimed Miss Holbrook, overwhelmed with horror. "Yes; I was very much surprised to see Jed in such company." "My poor brother must be quite unaware of this astounding fact!" "No doubt, Miss Holbrook. Jed is cunning. He wouldn't be very apt to tell your brother that he is a pauper." "A pauper! What a horrid thought! And that boy has actually the effrontery to push himself in among people of position. I can hardly believe it." "If you have any doubt about it, Miss Holbrook, just write a note to Mr. Simeon Fogson, and ask him what he thinks of Jed Gilman." "But I thought it was Mr. Avery who kept the poorhouse." "He did; but when my father became Overseer of the Poor," said Percy with conscious pride, "he removed the Averys and put in Mr. and Mrs. Fogson, whom he considered more fit for the office. The Averys were weak people and pampered the paupers." "Mr. Simeon Fogson, Scranton," Miss Holbrook entered on her tablets. "Really, Mr. Dixon, I am very much obliged to you for the important information you have given me, and so ought my brother to be. He
  • 73. has been very careless and indiscreet in engaging a boy of unknown antecedents, but it is fortunate that Chester has an aunt who is keenly alive to his interests." As she rose to go to her room to write to Mr. Fogson, Percy smiled. "Jed Gilman will find that his goose is cooked," he said to himself. "Won't he be astonished when the thunderbolt falls?"
  • 74. CHAPTER XVIII. MR. FOGSON RECEIVES A LETTER. Let us go back to the Scranton poorhouse. Mr. Fogson was sawing wood near the house. It was a task which Jed had been accustomed to do, but in his absence it devolved upon Mr. Fogson, who was very much disinclined to that form of labor, but still more to paying for having it done. He had thought of requiring Isaac Needham, one of the paupers, to do the sawing; but the old man, who was over seventy-five, proved physically unable to do the work, and very much against his will Mr. Fogson found himself compelled to undertake it himself. "Drat that Jed!" he muttered, as he stopped to mop his forehead with his red cotton handkerchief. "It's an outrage for him to throw his work on me. I wish I had him here this blessed minute and could give him a taste of the strap." At this point a neighbor's boy, Joe Coakley, entered the yard. "Here's a letter for you, Mr. Fogson," he said. "I guess it's from a lady." With considerable surprise Mr. Fogson took the letter in his hand. The envelope was square, and of fine paper, while the address was in a lady's handwriting. Mr. Fogson examined the postmark curiously. "Sea Spray!" he repeated. "Why, that's a fashionable watering-place. Who can have written me from there?" Just then Mrs. Fogson came out from the side door.
  • 75. "What letter have you there?" she asked. "It is from a lady, Mrs. F.," answered her husband with a grin. "What business has a lady writing to you?" demanded Mrs. Fogson suspiciously. "Really I don't know, as I have not read the letter." "Give it to me!" "No, thank you. I read my own letters." "Mr. Fogson, if you are engaged in a private correspondence with any lady I intend to find out all about it." "Don't be a fool, Mrs. F.; I don't know who the writer is, and I have never had a letter from her before." By this time he had opened the envelope, and his face quickly assumed an expression of interest. "It's about Jed," he exclaimed. "I'll read it to you." This was the letter: My Dear Sir: I am informed that you can give me information as to the past history of Jedediah Gilman. Some weeks ago my brother, Robert Holbrook, a well-known merchant of New York, engaged the boy as a companion and personal attendant of his young son Chester, without knowing much about him or taking the trouble to inquire. Having seen the boy, I have doubts as to whether he is a suitable companion for a boy in my nephew's high social station. I learn from young Mr. Percy Dixon, of your town, that you can give me full information as to the boy's antecedents. I shall feel indebted to you if you will take the trouble to communicate with me by letter.
  • 76. My brother is now in Chicago, and I am in temporary charge of my nephew. I feel that it is my duty to inquire into the character of a boy who by his intimate association with him may, if he is unworthy, do incalculable harm to his young and trustful nature. Yours very truly, Maria Holbrook, Spray Hotel, Sea Spray, N. J. "Well, upon my word!" ejaculated Mrs. Fogson. "So that young villain has wormed his way into the confidence of a rich New York merchant!" "Like a snake in the grass," suggested Simeon Fogson. "Exactly. It makes me shudder to think what an impostor he is. It is providential that Percy Dixon should find him out and show him up." "I'll show him up!" said Fogson, nodding. "I'll just write to Miss Holbrook, and tell her of his goin's on. I reckon he won't keep his place long after they get my letter." "You'd better let me write the letter, Simeon." "No, Mrs. F., the letter was addressed to me, and I'm goin' to answer it." "Just as you like, Mr. Fogson, but you are well aware that you are weak in your spelling." "Never mind, Mrs. F., I reckon I can make myself understood." "Just as you like, Fogson. Only make it strong enough." "You can trust me for that."
  • 77. CHAPTER XIX. DISCHARGED. In a front room on the second floor of the Spray Hotel sat Miss Maria Holbrook with a letter in her hand. It was written on the cheapest note-paper, and inclosed in a plebeian brown envelope. Of course it will be understood that it was the epistolary effort of Mr. Simeon Fogson. "Just as I thought!" soliloquized the lady. "This boy seems to be a disreputable character of the lowest antecedents, and utterly unworthy to associate even as a servant with a member of my family." Here Chester entered in his usual impetuous manner. "Oh, Aunt Maria," he cried, "I had a bully bath." "I am shocked to hear you use such a low term as 'bully,' Chester," said his aunt. "No doubt you learned it of Jedediah." "No, I didn't. Jed never uses the word. At least I never heard him." "Will you tell Jedediah that I wish to see him at once on important business?" "It seems funny to hear you call him Jedediah, Aunt Maria." "I apprehend that it is his right name; 'Jed' sounds low." "Well, I'll tell him to come up." When Jed made his appearance Miss Holbrook said: "You may go below, Chester. I wish to speak to Jedediah in private."
  • 78. "What's up now, I wonder?" thought Jed. The lady turned upon him a severe look. "Jedediah," she said, "is it true that your earlier years were spent at the Scranton poorhouse?" "Yes, madam," answered Jed, coloring. "Did you apprise my brother of this fact when he engaged you?" "No, madam. I suppose you learned it from Percy Dixon." "I learned it from young Mr. Dixon, but I could hardly believe it. He referred me to Mr. Simeon Fogson, of Scranton, and I have a letter from that gentleman in my hand. You probably will not care to read it." "I should like very much to read it, Miss Holbrook. I should like to know whether Mr. Fogson tells the truth." "Here is the letter, then." Jed read it with conflicting emotions. Respected Madam: I am glad to give you the informashun you ask about that young villen Jed Gilman, who ran away from the Poor House some weeks since after a violent assault on me, his offishul guardeen. Words cannot tell you how much trouble I have had with that boy. Likewise he has been very impident to Mrs. Fogson. The reeson is that he was too much indulged by my predicesors in offis Mr. and Mrs. Avery. I have tried to do my dooty by the boy, but as Squire Dixon, the Overseer will tell you my efforts has been in vane. I am not supprised that your brother was took in by Jed for he is the artfulest boy I ever seen. I hope for the sake of
  • 79. your young nefew's welfare you will discharge him at once and not allow him to corrup his youthful mind. Yours respectfully, Simeon Fogson. "Well," said Miss Holbrook triumphantly, "that doesn't seem to commend you very highly." "No," answered Jed, returning the letter to the envelope. "It is such a letter as I should expect Mr. Fogson to write." "Why?" "Because he is unfit for his place," answered Jed boldly. "He half starves the poor people under his charge, treats them roughly, and is detested by all." "He says you are impudent and troublesome." "I did not allow him to impose upon me." "He says you ran away." "I had a right to leave, as I felt able to support myself. I was recommended to do so by Dr. Redmond, the best physician in Scranton, who is a friend of mine." "I have listened to your side of the story," said Miss Holbrook coldly, "and the terms in which you speak of Mr. Fogson convince me that his charges are correct. Of course you will not expect me to keep you in charge of my nephew." "Will you wait till Mr. Holbrook returns?" pleaded Jed, who felt sad at the prospect of parting with Chester. "No; I shall not feel justified in doing so. I will pay you up to date, and assume the charge of Chester myself."
  • 80. She drew a bill from her pocket and handed it to Jed, who took it mechanically and left the room with a sober face. He was dismissed from his position in disgrace, a disgrace which he felt was not deserved. What was he to do next?
  • 81. CHAPTER XX. JED'S POOR PROSPECTS. Jed walked around to the office of his friend Harry Bertram. The telegraph operator noticed at once that he looked disturbed. "What has happened, Jed?" he asked. "I am discharged! That is all." "Discharged? Who discharged you?" "Miss Holbrook." "What is her reason? What have you done?" asked Bertram, much surprised. "I have done nothing, but she has discovered that I was brought up in the Scranton poorhouse," announced Jed despondently. "As if that made you any the worse!" ejaculated Bertram indignantly. "It isn't to my credit, at any rate. I am ashamed of it myself." "I don't know why you should be ashamed. You have left it, and are now earning your own living." "I was, but I am out of work now, and I may find it hard to get another position." "You can perhaps go back to the stage." "If I can take my part in the 'Gold King' I shall be satisfied," said Jed hopefully. "When will the season commence?" "September 7—three weeks from next Thursday."
  • 82. At that moment one of the bell boys came to the telegraph office with a letter in his hand. "I have a letter for you, Mr. Bertram," he said. "Ha! This is from Mordaunt. Now we shall know." He tore open the envelope hastily. His countenance fell, and he handed it in silence to Jed. This is the letter. Dear Bertram: Season of the Gold King opens at Jersey City on the seventh of September. As we shall have two new actors I shall call rehearsals for the Tuesday previous. Please report at Middleton Agency in New York on the first. John Mordaunt, Manager. P. S.—Ralph Clinton has recovered from his sickness, and will be ready to resume his part. "That settles it!" said Jed soberly, as he handed back the letter. "That opening is closed to me." "I am awfully sorry, Jed," returned Bertram in a tone of sympathy. "Perhaps if you enroll your name at the agency you can get a chance in some other play. I will speak a good word for you, and so I am sure will Mordaunt." Jed shook his head. "I don't think my chance would be very good," he said, "as I have had so little experience. Besides, it is three weeks from now. I must try to get work before then." "Stay here, Jed. I will pay your expenses."
  • 83. "Thank you, Mr. Bertram, but I have more than money enough for that, and you will need all yours. It will be better for me to leave Sea Spray, and go out in the world in search of work." "I hate to have you go, Jed. I shall feel lonesome." "So shall I, Mr. Bertram, but we are sure to meet again," said Jed with forced cheerfulness. "You must promise if things don't go well with you to write to me. You can learn from the Clipper or any of the dramatic papers where we are playing." "I'll promise that, Harry," said Jed, pressing the hand of his friend. "That's right, Jed! Don't call me Mr. Bertram again." "I will remember." "Don't go till to-morrow." "No, I won't. I shall need a little time to get ready." At this point a message came for Bertram to transmit, and Jed walked over to the beach, feeling dull and despondent. As he sauntered on slowly with his eyes on the sand some one called out, "Hallo, there!" Looking up, he met the gaze of Percy Dixon. "Where's Chester?" asked Percy. "In the hotel, I suppose." "Why isn't he with you?" "Because he is no longer under my charge," answered Jed eyeing Percy fixedly. "Ho, ho! you don't mean to say that you're bounced!" queried Percy, with a look of malicious pleasure.
  • 84. "That is about the size of it." "Well, I am surprised," returned Percy cheerfully. "What have you been up to?" "Nothing." "Then why are you discharged?" asked Percy with a look of innocent wonder. "I don't think you need ask, Percy Dixon," said Jed coldly. "If you had not made your appearance at Sea Spray I should have kept my place." "Ho, ho! What have I been doing, I should like to know?" asked Percy smiling. "I don't need to tell you. You told Miss Holbrook that I had been brought up in the Scranton poorhouse." "Well, it's true, isn't it?" "Yes, it is true, but you understood very well what would be the result of your communication." "As she asked me about you, I had to tell." "You gave her the name of Mr. Fogson, and led to her writing to him." "So he's written, has he." "Yes; Miss Holbrook showed me the letter this morning." "What did he say?" asked Percy, smiling. "Probably Miss Holbrook will show you the letter if you ask her." "I will. I should like to see what old Fogson says. He don't admire you very much." "There is no love lost between us."
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