what is operating system . introduction to OS

Agenda for Today
 Introduction and purpose of the course
 Organization of a computer system
 Purpose of a computer system—setting
the stage for OS concepts and principles
 Outline of topics to be discussed in the
course
 What is an operating system?
 Recap of the lecture
3 February 2020

1. Hardware
2. Operating system
3. Applications programs
4. Users
3 February 2020

 Computer systems consist of
software and hardware that
are combined to provide a tool
to solve specific problems in
an efficient manner
 Execute programs
3 February 2020

Computer System Hardware
Keyboard Mouse
PrinterRAM/ROM
HD
Mem
Bus
System Bus
Monitor
CD
Processor
Floating Point
Unit
Integer
Unit
Cache
Control
Unit
3 February 2020

Course Outline
 Operating system concepts
 Operating system structures
 Introduction to UNIX/Linux user interface
 Processes and threads—scheduling,
concurrency, synchronization, etc.
 Deadlocks
 Memory management
 Virtual memory
 File system
 Secondary storage management
3 February 2020

 Single-user systems
 Batch systems
 Multiprogrammed systems
 Time-sharing systems
 Real-time systems
 Interrupts, traps, and software interrupts
(UNIX signals)
 Hardware protection
3 February 2020

 Operating system services
 System calls
 Semantics of system call execution
 Operating system structures (monolithic,
microkernel-based, layered, virtual machines,
DOS-Windows, UNIX)
 System design and implementation
3 February 2020

Directory structure
Browsing directory structure
Useful commands
3 February 2020

 Process concept (process, states, attributes,
etc.)
 Process scheduling (scheduler)
 Context switching (dispatcher)
 Operations on processes (creation,
termination, signaling, suspend, foreground,
background, etc.)
 Process management in UNIX (fork, wait,
exec, exit, etc.)
3 February 2020

 Sample code for UNIX/Linux process
management
 Cooperating processes
 Interprocess communication (IPC)
 IPC in UNIX/Linux (pipe, FIFO, socket,
message queue, etc.)
3 February 2020

 Communication between UNIX/Linux
processes (pipe, mkfifo, read, write, close,
etc.)
 Sample code
 UNIX/Linux processes (process images,
control structures, etc. explained with sample
code)
 Managing UNIX/Linux processes (ps, top, fg,
bg, <Ctrl-Z>, <Ctrl-C>, etc.)
3 February 2020

Thread concept (thread, states,
attributes, etc.)
User- and kernel-level threads
POSIX threads (the pthread
library)
Sample code
3 February 2020

 Basic concepts
 Scheduling criteria
 Scheduling triggers
 Scheduling algorithms
 UNIX System V scheduling algorithm
 Optimal scheduling
 Algorithm evaluation
3 February 2020

 Basic concept
 The Critical Section Problem
 Solutions for the Critical Section Problem
 Software-based solutions—the Bakery
Algorithm
 Hardware-based solutions
 Semaphores
 Binary and counting semaphores
3 February 2020

 Classic problems of synchronization
 Deadlocks and starvation
 Critical regions
 Monitors
 Synchronization tools used in Solaris, Linux,
and Windows
 Deadlocks and starvation
 Pthread library functions
3 February 2020

 Basic concept
 Deadlock characterization
 Deadlock handling (prevention, avoidance,
detection and recovery)
 Banker’s algorithm
3 February 2020

 Basic concepts
 Various techniques for memory management
 Logical to physical address translation
 Swapping
 Contiguous memory allocation: MFT, MVT
 External fragmentation
 Paging
 Hardware support for paging
 Internal fragmentation
3 February 2020

 Performance of paging
 Protection and sharing
 Page table issues: Multi-level paging,
Hashed page tables, Inverted page tables
 Segmentation
 Protection and sharing
 Segmentation with paging
 Intel P4 example
3 February 2020

 Basic concept
 Demand paging
 Page fault
 Performance of demand paging
 Page replacement
 Allocation of frames
 Thrashing
 Operating-system examples
 Other considerations (I/O locking, page
size, …)
3 February 2020

 Basic concepts (file attributes, operations,
types, structure, etc.)
 Access methods (sequential, random, etc.)
 Directory structure
 UNIX/Linux directory structure (links in UNIX)
 File system mounting, sharing, and protection
 UNIX/Linux examples for sharing and
protection, and relevant commands (chmod, ln,
ln –s, etc.)
3 February 2020

 Basic concepts (overview of disk structure, file
structure, boot control block, super block,
inode, per process file descriptor table,
system-wide open-file table, etc.)
 Directory implementation
 Free space management methods
 Space Allocation Methods
 Time and space performance of allocation
methods
 Brief introduction to Network File System (NFS)
3 February 2020

Disk structure and scheduling
Disk management (formatting,
boot block, bad blocks, etc.)
Course Recap
3 February 2020

What is an Operating
System?
 A program that acts as an intermediary
between a user of a computer and the
computer hardware—provides the user a
simpler (virtual) machine to work with
 A program that allocates and deallocates
computer system resources in an efficient,
fair, and secure manner—a resource
manager
3 February 2020

 Execute user programs and make solving
user problems easier.
 Make the computer system convenient to
use.
 Use the computer hardware in an efficient
manner.
3 February 2020

what is operating system . introduction to OS

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