COP 4610:Introduction to Operating Systems
CGS 5765: Principles of Operating Systems
Instructor: Xiuwen Liu
Department of Computer Science
Florida State University
Please pick up the syllabus from the front
Outline
• Class organization
– Syllabus
• Programming environment at Computer
Science
• Introduction to Operating Systems
• A survey
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Class organization
• Class syllabus
• Class web page
• Comments
– Grading
– Academic honor code
• Programs you submitted must be your own
• While discussions of class materials and assignments
are allowed, discussion and copying of solutions is
strictly prohibited.
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Class Email List
• Class email list
– I sent a message with the subject “We are going
to have the first recitation on Aug. 27” on
Monday, Aug. 25
– If you have not received the email, or would like
to use another email, please send me an email
with your email address
• Some of you did not receive the message because of
problems such as wrong email address in your record
– I will send important announcements through the
mailing list
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Recitation Session
• Recitation session will be taught by the
instructor
• You are required to attend the same session
as you registered
• Recitation session will focus on
– Questions and answers
– Programming examples
– First recitation session is this Wednesday, Aug.
27.
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Textbook
• You are required to read the chapters in the textbook
– You can skip sections only when specified
– You are NOT required to read programming examples in
the dotted boxes
– However, you are required to know programming
examples given in class and those related to programming
projects
• You may be tested on the materials in the textbook
but not fully covered in the class
– I will specify those sections clearly for self studying
– The majority on quizzes and exams will be covered in the
class
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Textbook - continued
• Some comments on the textbook
– This class focuses on basic principles
– All the programming assignments will be done in
Unix / Linux environment
– Comments from amazon.com
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Programming Environment
• linprog consists of four linux machines
• program consists of four Sun workstations
– Three programming assignments must be done
on either linprog or program
– Doing the assignments on other machines is not
allowed
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Programming Environment – cont.
• Access
– ssh to those machines
• ssh linprog
• ssh program
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Linux/Unix Tutorial
• You are expected to know how to use
Linux/Unix
–
–
–
–
How to edit a program – e.g., emacs, pico, vi
How to compile a program – gcc, g++
How to run a program
How to navigate through your files – cd, mkdir,
mv, rm, rmdir, ls
• On-line resources
– Unix Guide
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Expectations
• You are expected to have a strong desire to
learn something new (and may be difficult
sometimes)
• You are expected to be an Operating System
expert
• You are expected to know how to read and
understand manuals
– System calls
– Unix commands
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Expectations – cont.
• System call manual pages
– Syntax
• Function prototype
• How to call a function
– Semantics
• The meanings of the function
• What it does with different parameter values
• fork example
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System Overview
• A computer system consists of hardware and
software that are combined to provide a tool
to solve specific problems
– Hardware includes CPU, memory, disks, printers,
screen, keyboard, mouse ...
– Software includes
• System software
– A general environment to create specific applications
• Application software
– A tool to solve a specific problem
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System Overview – cont.
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Hardware Resources
• Processor: execute instructions
• Memory: store programs and data
• Input/output (I/O)controllers: transfer to and
from devices
• Disk devices: long-term storage
• Other devices: conversion between internal
and external data representations
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Hardware Resources – cont.
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Hardware Interface – cont.
• Everything that a programmer needs to know
in order to write programs that perform
desired operation on the hardware
– Disk drive is an example
• Disk interface provides functions to move disk head,
transfer data
– Monitor
• Monitor interface provides functions to move the
cursor, display characters/graphics
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Software Classification
• System software
– Provides a general programming environment in
which programmers can create specific
applications
• Application software
– Intended to solve a specific problem
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Software Classification - continued
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What is an Operating System?
• The operating system is the part of the
system software that manages the use of the
hardware used by other system software and
all application software
– It is the system program that acts between the
hardware and the user programs
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What is an Operating System? - continued
• It provides services to user programs
– Through system calls / message passing
• File system services
• Memory services
• I/O services
• It hides hardware from user programs
– When your program shows a message on the monitor, it
does not need to know the details
– When your program generates a new file, it does not need
to where the free space is on your hard drive
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Differences between OS and System Software
• Major differences between OS and general
system software
– General system software relies on the
abstractions provided by OS
– OS abstracts the hardware directly
– OS provides the fundamental trusted mechanisms
for resource sharing
– A general purpose OS is domain-independent
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Operating System Functions
• Resource manager
– manage hardware and software resources
– Resource abstraction and sharing
• A nicer environment
– implement a virtual machine for processes to run in
• A program in execution is called a process
– a nicer environment than the bare hardware
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Resource Management Functions
• Transform physical resources to logical
resources
– Resource abstraction
• Make the hardware resources easier to use
• Multiplex one physical resource to several
logical resources
– Create multiple, logical copies of resources
• Schedule physical and logical resources
– Decide who gets to use the resources
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Resource Abstraction
• Provides an abstract model of the operation
of hardware components
– Like data abstraction in Object-Oriented
programming
• Interface functions
• Internal functions and status
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A Disk Device Abstraction
• Three interface functions
– Load(block, length, device)
– seek(device, track)
– out(device, sector)
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A Disk Device Abstraction – cont.
• An abstract function for writing
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Resource Abstraction – cont.
• Multi-level abstractions
– Disk controller -> disk driver -> file system
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Resource Sharing
• Two types of sharing
– Time multiplexed sharing
• time-sharing
• schedule a serially-reusable resource among several
users
– Space multiplexed sharing
• space-sharing
• divide a multiple-use resource up among several users
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Time-multiplexing the Processor
- Called multiprogramming
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Time-multiplexing the Processor – cont.
- Resulted in concurrent execution or concurrency
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Time-multiplexing the Processor – cont.
- Multiprogramming can improve the overall system performance
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Space-multiplexing Memory
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Time-multiplexing I/O Devices
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Space-multiplexing the Disk
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Issues in Resource Sharing
• Resource isolation and sharing
– Protection
– Sharing
• Resource allocation
– Scheduling
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Survey
• This survey consists of a few questions
– The purpose is to give me a better knowledge of
your background so that I may do a better job
– It will be used as evidence for attendance
– It will not be used for any grading
• We will have the first recitation this week
– This Wednesday, Aug. 27, 2001
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