Class 1: What is an Operating System?
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The document is an introduction to an operating systems course (CS4414) at the University of Virginia, taught by David Evans. It outlines the definition of an operating system, its functions in managing hardware and providing abstractions for application programs, and emphasizes the importance of understanding how computers work for better programming skills. The course aims to convey complex ideas and enhance student engagement through projects, including programming in Rust.
![What’s
an
opera0ng
system?
You
might
say
it’s
what’s
between
you
and
the
hardware,
but
that
would
cover
prey
much
all
so]ware.
So
let’s
say
it’s
the
so]ware
that
sites
between
your
so]ware
and
the
hardware.
But
does
that
mean
that
the
library
you
picked
up
from
some
web
site
is
part
of
the
opera0ng
system?
We
probably
want
our
opera0ng-‐system
defini0on
to
be
a
bit
less
inclusive.
So,
let’s
say
that
it’s
that
so2ware
that
almost
everything
else
depends
upon.
This
is
s0ll
vague,
but
then
the
term
is
used
in
a
rather
nebulous
manner
throughout
the
industry.
Perhaps
we
can
do
beer
by
describing
what
an
opera0ng
system
is
actually
supposed
to
do.
From
a
programmer’s
point
of
view,
opera&ng
systems
provide
useful
abstrac&ons
of
the
underlying
hardware
facili&es.
Since
many
programs
can
use
these
facili0es
at
once,
the
opera&ng
system
is
also
responsible
for
managing
how
these
facili&es
are
shared.
$149.9
5
6](https://image.slidesharecdn.com/class1inked140114-140114213849-phpapp02/85/Class-1-What-is-an-Operating-System-6-320.jpg)
![There
is
a
body
of
so]ware,
in
fact,
that
is
responsible
for
making
it
easy
to
run
programs
(even
allowing
you
to
seemingly
run
many
at
the
same
0me),
allowing
programs
to
share
memory,
enabling
programs
to
interact
with
devices,
and
other
fun
stuff
like
that.
That
body
of
so]ware
is
called
the
opera&ng
system,
as
it
is
in
charge
of
making
sure
the
system
operates
correctly
and
efficiently
in
an
easy-‐to-‐use
manner.
$0.00
(
$29)
7](https://image.slidesharecdn.com/class1inked140114-140114213849-phpapp02/85/Class-1-What-is-an-Operating-System-7-320.jpg)
Class 1: What is an Operating System?
- 1. Class 1: Introduc0on cs4414 Spring 2014 rust-‐class.org University of Virginia David Evans
- 2. Plan for Today • What is an Opera0ng System? • Course Overview • Introducing Rust 2
- 3. What is an Opera0ng System? 3
- 4. An opera&ng system is a program that manages a computer’s hardware. It also provides a basis for applica0on programs and acts as an intermediary between the computer user and the computer hardware. An amazing aspect of opera0ng systems is how they vary in accomplishing these tasks. Mainframe opera0ng systems are designed primarily to op0mize u0liza0on of hardware. Personal computer (PC) opera0ng systems support complex games, business applica0ons, and everything in between. Opera0ng systems for mobile computers provide an environment in which a user can easily interface with the computer to execute programs. Thus, some opera0ng systems are designed to be convenient, others to be efficient, and others to be some combina0on of the two. 4
- 5. 6.00 $18 It is hard to pin down what an opera0ng system is other than saying it is the so2ware that runs in kernel mode – and even that is not always true. Part of the problem is that opera0ng systems perform two basically unrelated func0ons: providing applica0on programmers (and applica0on programs, naturally) a clean abstract set of resources instead of the messy hardware ones and managing these hardware resources. 5
- 6. What’s an opera0ng system? You might say it’s what’s between you and the hardware, but that would cover prey much all so]ware. So let’s say it’s the so]ware that sites between your so]ware and the hardware. But does that mean that the library you picked up from some web site is part of the opera0ng system? We probably want our opera0ng-‐system defini0on to be a bit less inclusive. So, let’s say that it’s that so2ware that almost everything else depends upon. This is s0ll vague, but then the term is used in a rather nebulous manner throughout the industry. Perhaps we can do beer by describing what an opera0ng system is actually supposed to do. From a programmer’s point of view, opera&ng systems provide useful abstrac&ons of the underlying hardware facili&es. Since many programs can use these facili0es at once, the opera&ng system is also responsible for managing how these facili&es are shared. $149.9 5 6
- 7. There is a body of so]ware, in fact, that is responsible for making it easy to run programs (even allowing you to seemingly run many at the same 0me), allowing programs to share memory, enabling programs to interact with devices, and other fun stuff like that. That body of so]ware is called the opera&ng system, as it is in charge of making sure the system operates correctly and efficiently in an easy-‐to-‐use manner. $0.00 ( $29) 7
- 8. Do we like any of these defini0ons? 8
- 10. Simplis0c View of Compu0ng Systems Applica0ons Opera0ng System Hardware 10
- 11. More Realis0c View Applica0ons Opera0ng System Hardware 11
- 12. cs4414 OS Defini0on An opera&ng system is a program that manages resources and provides abstrac&ons. 12
- 13. Main Ideas in cs4414 Managing Resources How do you share processors, memory, and hardware devices among programs? Providing Abstrac&ons How do you provide programs with clean and easy to use interfaces to resources, without sacrificing (too much) efficiency and flexibility? 13
- 14. Does it have an Opera0ng System? 14
- 15. Apple II 1977 15
- 16. 16
- 17. ✖ Manage Resources ✔ Provide Abstrac0ons 17
- 18. 18
- 19. Not just one opera0ng system, but dozens of them! 19
- 20. Does it have an Opera0ng System? 20
- 21. 21
- 23. Cool Compu0ng Stuff Its all magic! Physics Minimizing Magic 23
- 24. Cool Compu0ng Stuff Its all magic! Four Years Studying Compu0ng at an Elite Public University Physics Minimizing Magic 24
- 25. Cool Compu0ng Stuff Its all understandable! (and I can do magical things!) Its all magic! Four Years Studying Compu0ng at an Elite Public University Physics Minimizing Magic 25
- 26. Cool Compu0ng Stuff Its all magic! cs1110 By the 0me you graduate, nothing should be “magic” other than how transistors work and NP-‐Completeness. Physics Minimizing Magic 26
- 27. Cool Compu0ng Stuff cs3102 Its all magic! cs1110 cs2110 cs2150 By the 0me you graduate, nothing should be “magic” other than how transistors work and NP-‐Completeness. cs2150 cs3330 cs2330 Physics Minimizing Magic 27
- 28. Cool Compu0ng Stuff cs4414 cs3102 Its all magic! cs1110 cs2110 cs2150 cs4414 By the 0me you graduate, nothing should be “magic” other than how transistors work and NP-‐Completeness. cs2150 cs3330 cs4414 cs2330 Physics Minimizing Magic 28
- 29. Cool Compu0ng Stuff elec0ves cs4414 cs3102 Its all magic! cs1110 cs2110 cs4610 cs2150 cs4414 By the 0me you graduate, nothing should be “magic” other than how transistors work and NP-‐Completeness. cs2150 cs3330 cs4414 cs2330 Physics Minimizing Magic 29
- 30. (Academic) Goal of the Class Improve our understanding of how computers work. 30
- 31. (Academic) Goal of the Class Improve our understanding of how computers work. Not: 31
- 32. Why bother? 1. Beer understanding of how computers work make you a beEer programmer which will help you build something cool, succeed in grad school, or get a more interes0ng job. 2. Beer understanding of how computers work (and why) is intellectually, culturally, and scien&fically interes&ng. 32
- 33. Why bother? 1. Beer understanding of how computers work make you a beEer programmer which will help you build something cool, succeed in grad school, or get a more interes0ng job. 2. Beer understanding of how computers work (and why) is intellectually, culturally, and scien&fically interes&ng. 33
- 34. Why bother? 1. Beer understanding of how computers work make you a beEer programmer which will help you build something cool, succeed in grad school, or get a more interes0ng job. 2. Beer understanding of how computers work (and why) is intellectually, culturally, and scien&fically interes&ng. 34
- 35. Why bother? 1. Beer understanding of how computers work make you a beEer programmer which will help you build something cool, succeed in grad school, or get a more interes0ng job. 2. Beer understanding of how computers work (and why) is intellectually, culturally, and scien&fically interes&ng. If these reasons don’t apply for you and you are only in this class because there is a bureaucra&c requirement that you take it so some Dean will hand you a nice bit of paper in front of your parents, you should meet with me to figure out an alterna0ve. 35
- 36. What Mr. Jefferson Wants 36
- 37. What Mr. Jefferson Wants “We wish to establish in the upper country of Virginia, and more centrally for the State, a University on a plan so broad and liberal and modern, as to be worth patronizing with the public support, and be a tempta&on to the youth of other States to come and drink…” TJ’s leer to Joseph Priestly, 1800 No Majors No Degrees No President 37
- 38. Note: this does not mean he wants you to be lazy: : Thomas Jefferson enrolled in the College of William and Mary on March 25, 1760, at the age of 16… By the 0me he came to Williamsburg, the young scholar was proficient in the classics and able to read Greek and La0n authors in the original… He was instructed in natural philosophy (physics, metaphysics, and mathema&cs) and moral philosophy (rhetoric, logic, and ethics). A keen and diligent student, he displayed an avid curiosity in all fields and, according to family tradi0on, he frequently studied fi2een hours a day. 38 hp://www.wm.edu/about/history/tjcollege/tjcollegelife/
- 39. What is my goal for lectures? Convey some complex technical ideas Teach you what you need to know to do the projects Avoid being fired Keep most of you awake for 75 minutes Get you to laugh at dumb jokes 39
- 40. What is my goal for lectures? Lectures are a horrible medium for learning complex ideas. Convey some complex technical ideas Beer to read wikipedia. Teach you what you need to know to do the projects Avoid being fired Keep most of you awake for 75 minutes Get you to laugh at dumb jokes 40
- 41. What is my goal for lectures? Lectures are a horrible medium for learning complex ideas. Convey some complex technical ideas Beer to read wikipedia. The point of the projects is to teach you things I want you to Teach he class (mostly by sugges0ng tto know hould o learn in t you what you need hings you s to d learn o rojects the pn your own). Avoid being fired Keep most of you awake for 75 minutes Get you to laugh at dumb jokes 41
- 42. What is my goal for lectures? Lectures are a horrible medium for learning complex ideas. Convey some complex technical ideas Beer to read wikipedia. The point of the projects is to teach you things I want you to Teach he class (mostly by sugges0ng tto know hould o learn in t you what you need hings you s to d learn o rojects the pn your own). I have Avoid being fired tenure already Keep most of you awake for 75 minutes Get you to laugh at dumb jokes 42
- 43. What is my goal for lectures? Lectures are a horrible medium for learning complex ideas. Convey some complex technical ideas Beer to read wikipedia. The point of the projects is to teach you things I want you to Teach he class (mostly by sugges0ng tto know hould o learn in t you what you need hings you s to d learn o rojects the pn your own). I have Avoid being fired tenure already You probably should be gerng more inutes Keep most of you awake for 75 msleep! Get you to laugh at dumb jokes 43
- 44. What is my goal for lectures? Lectures are a horrible medium for learning complex ideas. Convey some complex technical ideas Beer to read wikipedia. The point of the projects is to teach you things I want you to Teach he class (mostly by sugges0ng tto know hould o learn in t you what you need hings you s to d learn o rojects the pn your own). I have Avoid being fired tenure already You probably should be gerng more inutes Keep most of you awake for 75 msleep! Monty Python ils funnier (unless you are Kevin Redmon) Get you to augh at dumb jokes 44
- 45. My Real Goal for Lectures Provide context and meaning for the things you have or will later learn on your own. (I also have an insidious goal for lectures, that I won’t tell you about un0l later…) 45
- 47. The Problem Sets are Sugges&ons If you have a beEer idea, convince me, and you should do that instead. 47
- 48. Plan for Projects PS0 (Friday): Rust tutorial and course survey PS1 (23 Jan): zhEpto web server PS2 (9 Feb): gash (learn about processes) PS3 (3 March): zhEa web server (learn about synchroniza0on, memory management) PS4 (2 April): hacking a (rela0vely simple) kernel 48
- 49. This genera0on of students got into “UVa” by doing exactly and precisely what teacher wants. If teacher is vague about what he wants, they work a lot harder to figure out what they want and whether or not it is good. The vaguer the direc&ons, the more likely the opportunity for serendipity to happen. It drives them nuts! Harvard Professor John S0lgoe (on "60 Minutes", 4 January 2004) 49
- 50. Final Project Final Project (29 April): (almost*) anything you want! * must be at least two of: fun, technically interes0ng, useful, relevant Start thinking of ideas now – if you come up with something sufficiently worthwhile, can subs0tute for PS4/PS3/PS2/etc. 50
- 51. Some Examples hp://uvasear.ch/ Nishant Shukla Jasdev Singh 51
- 52. Norvigtorious Alex Fabian Daniel Nizri Renee Seaman Casey Silver 52
- 53. IronKernel Kevin Broderick Alex Lamana Zeming Lin John Stevans Wil Thomason We will use this for PS4! 53
- 54. 54
- 55. 55
- 56. Kiet Tran 56
- 57. Why learn a new programming language? 57
- 58. “Jamais Jamais Jamais” from Harmonice Musices Odhecaton A. (1501) J S Bach, “Coffee Cantata”, BWV 211 (1732) www.npj.com/homepage/teritowe/ jsbhand.html 58
- 59. Modern Music Nota0on Roman Haubenstock-‐ Rama0, Concerto a Tre John Cage, Fontana Mix hp://www.medienkunstnetz.de/works/fontana-‐mix/audio/1/ 59
- 60. 60
- 61. 61
- 62. Thought and Ac0on Languages change the way we think BASIC: think about GOTO Algol, Python: think about assignments, control blocks Scheme, Haskell: think about procedures Java, C++: think about types, objects Languages provide abstrac&ons of machine resources – Hide dangerous/confusing details: memory loca0ons, instruc0on opcodes, number representa0ons, calling conven0ons, etc. – Hiding more increases simplicity, but limits control 62
- 63. Why so many programming languages? 63
- 64. Fundamental Differences All equivalently powerful! – Universal languages: all capable of simula0ng each other Fundamental differences Expressiveness: how easy it is to describe a computa0on Control: how much programmer can control machine “Truthiness”: likelihood program means programmer wants Safeness: impact of programmer mistakes Difficult to achieve all of these at once 64
- 65. Fundamental Differences All equivalently powerful! – Universal languages: all capable of simula0ng each other Fundamental differences Expressiveness: how easy it is to describe a computa0on Control: how much programmer can control machine “Truthiness”: likelihood program means programmer wants Safeness: impact of programmer mistakes Difficult to achieve all of these at once 65
- 66. Fundamental Differences All equivalently powerful! – Universal languages: all capable of simula0ng each other Fundamental differences Expressiveness: how easy it is to describe a computa0on Control: how much programmer can control machine “Truthiness”: likelihood program means programmer wants Safeness: minimize impact of programmer mistakes Difficult to achieve all of these at once 66
- 67. Fundamental Differences All equivalently powerful! – Universal languages: all capable of simula0ng each other Fundamental differences Expressiveness: how easy it is to describe a computa0on Control: how much programmer can control machine “Truthiness”: likelihood program means programmer wants Safeness: minimize impact of programmer mistakes Difficult to achieve all of these at once What do we want for systems programming? 67
- 68. Programming Language Design Space Expressiveness high low more mistake prone less mistake prone “Truthiness” 68
- 69. Programming Language Design Space Expressiveness high Scheme Python (display “Hello!”) print ("Hello!") BASIC C strict typing, sta0c C++ Java Ada Spec# low more mistake prone less mistake prone “Truthiness” 69
- 70. Programming Language Design Space Control high low very risky Safety fairly safe 70
- 71. Programming Language Design Space high Control C Java Python low very risky Safety fairly safe 71
- 72. “a safe, concurrent, prac0cal language” Its design is oriented toward concerns of “programming in the large”, that is, of crea0ng and maintaining boundaries – both abstract and opera0onal – that preserve large-‐system integrity, availability and concurrency. from hp://www.rust-‐lang.org/ Rust Advances in programming language design and compiler implementa0on make it possible to get both control and safety, and mostly get expressiveness and “truthiness” all at the same 0me! 72
- 73. Charge Bring a laptop to use in Thursday’s class! • Do (or at least aempt) everything on the Class 1 notes Ac&on Items before class Thursday – Download and setup your compu0ng environment for cs4414 – Setup your github account • Next class: – Help gerng everything working on your machine – Help gerng started with Rust (Rust tutorial) 73