Welcome to CS314 Operating Systems A Quick Tour for Introduction to OS Department of Computer Science Southern Illinois University Edwardsville Spring, 2019 Dr. Hiroshi Fujinoki E-mail: hfujino@siue.edu OS_Intro/001

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

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

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

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

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

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

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

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

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

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

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

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

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

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