4_unix

4_unix - Part 4: Unix Operating System CS252: Systems...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Part 4: Unix Operating System CS252: Systems Programming Ramana Kompella Computer Science Department Purdue University What is an Operating System q An Operating System (OS) is a program that sits in between the hardware and the user programs. q It provides: Ø Multitasking - Multiple processes running in the same computer Ø Multiuser - Multiple users using the same computer Ø File system – Storage Ø Networking – Access to the network and internet 2 What is an Operating System Ø Window System – Graphical use interface Ø Standard Programs – Programs such as a web browser, task manager, editors, compilers etc. Ø Common Libraries – Libraries common to all programs running in the computer such as math library, string library, window library, c library etc. Ø It has to do all of the above in a secure and reliable manner. 3 A Tour of UNIX q We will start by describing the UNIX operating system (OS). q Understanding one instance of an Operating System will help us understand other OSs such as Windows, Mac OS, Linux etc. q UNIX is an operating system created in 1969 by Ken Thompson, Dennis Ritchie, Brian Kernighan, and others at AT&T Bell Labs. q UNIX was a successor of another OS called MULTICS that was more innovative but it had many problems. q UNIX was smaller, faster, and more reliable than MULTICS. 4 A Tour of UNIX q UNIX was initially created to support typesetting (edition of documents). q By having the programmers being the users themselves of the OS (eat your own food), UNIX became the robust, practical system that we know today. q UNIX was written in l C z (95%) and assembly language (5%). q This allowed UNIX to be ported to other machines besides Digital Equipment (DEC) ` s PDP11. 5 BSD UNIX q UNIX was a success in the universities. q Universities wanted to modify the UNIX sources for experimentation, so Berkeley created its own version of UNIX called BSD-UNIX. q POSIX is an organization that created the POSIX UNIX standard to unify the different flavors of UNIX. q Sockets, FTP, Mail etc came from BSD UNIX. 6 UNIX File System q UNIX has a hierarchical File System q Important directories / - Root Directory /etc OS Configuration files /etc/passwd – User information /etc/groups – Group information /etc/inetd.conf – Configuration of Internet Services (deamons) /etc/rc.*/ - OS initialization scripts for different services. q Deamons – Programs running in the background implementing a service. (Servers). 7 UNIX File System /dev – List of devices attached to the computer /usr – Libraries and tools /usr/bin – Application programs such as grep, ls et /usr/lib – Libraries used by the application programs /usr/include – Include files (.h) for the libraries /home – Home directories 8 Users q UNIX was designed as a multiuser system....
View Full Document

This note was uploaded on 03/06/2012 for the course CS 252 taught by Professor Gustavorodriguez during the Spring '11 term at Purdue.

Page1 / 68

4_unix - Part 4: Unix Operating System CS252: Systems...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online