1. Welcome to CS314 Operating Systems A Quick Tour for Introduction to OS
Department of Computer Science
Southern Illinois University Edwardsville
Fall, 2018
Dr. Hiroshi Fujinoki
OS_Intro/001

2. CS 314 Operating Systems Presentation Agenda What is Operating System?
Why do we need Operating Systems?
( = Why not just application programming?)
What kinds of Operating Systems exist?
What are we going to learn in this course?
What are we NOT going to learn in this class?
OS_Intro/002

3. CS 314 Operating Systems What is Operating System?
(1) A middleman between you (as a user) and computer hardware
You (or your program)
command!
Why not?
Without the middleman (OS),
you (your programs) have to know
how to directly control hardware
Computer Hardware
OS_Intro/003

4. CS 314 Operating Systems What is Operating System?
(1) A middleman between you (as a user) and computer hardware
You need to manage:
everything such as
 Controller chips
 Each I/O device
 and more ...
Computer Hardware
OS_Intro/004

5. directly control hardware
CS 314 Operating Systems
What is Operating System?
(1) A middleman between you (as a user) and computer hardware
You (or your program)
command!
OS is the software that
directly control hardware
As high-level commands
(e.g. “READ My_File.txt”) OS
Low-level commands
“Read Sectors 1E to 4F”
Computer Hardware
OS_Intro/005

6. CS 314 Operating Systems What is Operating System (continued)?
(2) The government in your computer (the agent that allocate resources)
Program A
Program B
Program C
Program D
Request resources
Request resources
A Computer
CPU
Memory
Disk
Keyboard
Network
Etc.
OS_Intro/006

7. CS 314 Operating Systems OS If you DO have an OS … CPU Memory Disk
Program A
Program B
Program C
Program D OS
CPU
Memory
Disk
Printer
Network
Etc.
OS_Intro/007

8. CS 314 Operating Systems What is Operating System (continued)?
(2) The government in your computer (the agent that allocate resources)
You (or your program)
command!
Another
User
Computer hardware can not be
shared by more than one user
(or more than one program)
If the resource being used is
printer, the output will be
gibberish!
Computer Hardware
OS_Intro/008

9. CS 314 Operating Systems OS What is Operating System (continued)?
(2) The government in your computer (the agent that allocate resources)
You (or your program)
command!
Another User
“print”
Manage (serialize)
I/O requests from users OS
Computer Hardware
OS_Intro/009

10. CS 314 Operating Systems
The three-layer structure in a computer system
You (as a user)
High-level
commands
APIs
(System Calls)
Low-level
Commands
(Assembly Routines)
Computer Hardware
Operating System
Application Programs
OS_Intro/010

11. CS 314 Operating Systems Summary for “What is Operating System”
(1) OS is the software that directly control hardware
(2) OS is a middleman between you (as a user) and computer hardware
that hides details of hardware
OS provides “hardware abstraction”
(3) OS is the government in your computer (the agent that allocate resources)
OS provides “resource management” in your computer
OS_Intro/011

12. CS 314 Operating Systems What kinds of Operating Systems exist?
General Purpose OS:
UNIX, MS-DOS, Windows, Be-OS
Network OS:
Novell Netware, NFS, Windows-NT
Embedded OS:
TRON (I-TRON - Univ. of Tokyo)
Real-time OS:
RxDOS (Computer Wave)
Special Purpose (e.g., for super computers):
AIX (UNIX for Deep Blue, ASCI White)
IRIX (UNIX for Render Farm)
Research prototypes:
Amoebas (U. of Amsterdam), EROS (U. of Pennsylvania)
OS_Intro/012

13. CS 314 Operating Systems What is this course about?
What is this course NOT about?
Identifying major components in modern operating systems
Understand the purpose of each OS component
Understand how each OS component works
Performance analysis for different implementations of an OS component
Survey for advanced operating systems
How to use Windows XP
(We may discuss it to compare to other operating systems)
Develop an operating system
OS_Intro/013

14. CS 314 Operating Systems Major components in modern operating systems
(2) Memory management
(1) Process management (= allocating CPU resource)
(3) I/O resource management
(4) User management
Process and thread (light-weight process)
Inter-Process Communication (IPC)
Process Synchronization
Paging
Virtual memory
Segmentation
Deadlock avoidance
Security
OS_Intro/014

15. Why do I need to learn OS? CS 314 Operating Systems
Let’s talk about it before we start this course …..
OS_Intro/015