COP%204610:Introduction%20to%20Operating%20Systems%20CGS%205765:%20Principles%20of%20Operating%20Systems

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COP 4610Introduction to Operating SystemsCGS
5765 Principles of Operating Systems

• Instructor Xiuwen Liu
• Department of Computer Science
• Florida State University

Please pick up the syllabus from the front
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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 -gt disk driver -gt 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