tailieunhanh - Lecture Operating system concepts - Lecture 28

Discuss basic concepts related to concurrency, such as race conditions, OS concerns, and mutual exclusion requirements; understand hardware approaches to supporting mutual exclusion; define and explain semaphores; define and explain monitors;. | CSC 322 Operating Systems Concepts Lecture - 31: by Ahmed Mumtaz Mustehsan Special Thanks To: . Sarwar, R. Koretsky and . Sarwar, Linux – The Textbook, Operating Systems, by Addison Wesley, 1st ed, 2002 Ahmed Mumtaz Mustehsan, GM-IT, CIIT, Islamabad 1 2 Case study: Linux Lecture-31 Ahmed Mumtaz Mustehsan, GM-IT, CIIT, Islamabad Features of modern OS Provide a user interface Organize files on disk Allocating resource to different users with security control Co-ordinate programs to work with devices and other programs 3 Lecture-31 Ahmed Mumtaz Mustehsan, GM-IT, CIIT, Islamabad 4 Before Linux In 80’s, Microsoft’s DOS was the dominated OS for PC Apple MAC is better, but expensive UNIX is much better, but much much expensive. Only for minicomputer for commercial applications People were looking for a UNIX based system, which is cheaper and can run on PC Both DOS, MAC and UNIX are proprietary, ., the source code of their kernel is protected No modification is possible without . | CSC 322 Operating Systems Concepts Lecture - 31: by Ahmed Mumtaz Mustehsan Special Thanks To: . Sarwar, R. Koretsky and . Sarwar, Linux – The Textbook, Operating Systems, by Addison Wesley, 1st ed, 2002 Ahmed Mumtaz Mustehsan, GM-IT, CIIT, Islamabad 1 2 Case study: Linux Lecture-31 Ahmed Mumtaz Mustehsan, GM-IT, CIIT, Islamabad Features of modern OS Provide a user interface Organize files on disk Allocating resource to different users with security control Co-ordinate programs to work with devices and other programs 3 Lecture-31 Ahmed Mumtaz Mustehsan, GM-IT, CIIT, Islamabad 4 Before Linux In 80’s, Microsoft’s DOS was the dominated OS for PC Apple MAC is better, but expensive UNIX is much better, but much much expensive. Only for minicomputer for commercial applications People were looking for a UNIX based system, which is cheaper and can run on PC Both DOS, MAC and UNIX are proprietary, ., the source code of their kernel is protected No modification is possible without paying high license fees Lecture-31 Ahmed Mumtaz Mustehsan, GM-IT, CIIT, Islamabad 5 GNU project Established in 1984 by Richard Stallman, who believes that software should be free from restrictions against copying or modification in order to make better and efficient computer programs GNU is a recursive acronym for “GNU's Not Unix” Aim at developing a complete Unix-like operating system which is free for copying and modification Companies make their money by maintaining and distributing the software, . optimally packaging the software with different tools (Redhat, Slackware, Mandrake, SuSE, etc) Stallman built the first free GNU C Compiler in 1991. But still, an OS was yet to be developed Lecture-31 Ahmed Mumtaz Mustehsan, GM-IT, CIIT, Islamabad 6 Beginning of Linux A famous professor Andrew Tanenbaum developed Minix, a simplified version of UNIX that runs on PC Minix is for class teaching only. No intention for commercial use In Sept 1991, Linus Torvalds, a second year student of .