PRESENTATION ONOPERATING SYSTEM & AND UNIX FOR BCA-IV AJIT SINGH ASSISTANT PROFESSOR
CURRICULUM• Operating System Organization and Unix• External Marks: 80• Internal Marks: 20• Time : 3 Hrs
Operating SystemThe operating system is the most important program thatruns on a computer. Every general-purpose computermust have an operating system to run other programs.Operating systems perform basic tasks, such asrecognizing input from the keyboard, sending output tothe display screen, keeping track of files and directorieson the disk, and controlling peripheral devices such asdisk drives and printers.
Types of Operating Systems• Multi-user: Allows two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users.• Multiprocessing : Supports running a program on more than one CPU.• Multitasking : Allows more than one program to run concurrently.• Multithreading : Allows different parts of a single program to run concurrently.• Real time: Responds to input instantly. General-purpose operating systems, such as DOS and UNIX, are not real-time.• Embedded System: The operating systems designed for being used in embedded computer systems are known as embedded operating systems.
Unix Operating SystemUNIX is a powerful computer operating system originallydeveloped at AT&T Bell Laboratories. It is very popular among thescientific, engineering, and academic communities due to its multi-user and multi-tasking environment, flexibility and portability,electronic mail and networking capabilities, and the numerousprogramming, text processing and scientific utilities available. Ithas also gained widespread acceptance in government andbusiness. Over the years, two major forms (with several vendor’svariants of each) of UNIX have evolved: AT&T UNIX System V andthe University of California at Berkeley’s Berkeley SoftwareDistribution (BSD).
Unix Operating System • Minix (study OS developed by Andrew S. Tanenbaum in the Netherlands)Research Unix-like • Solaris, contains original Unix (SVR4) codeand other POSIX- • Unix (OS developed at Bell Labs ca 1970 initially by Ken Thompson) compliant • Xinu, (Study OS developed by Douglas E. Comer in the USA) • DesktopBSD FreeBSD distribution for desktop useFree/Open source • PC-BSD FreeBSD distribution for desktop use Unix-like • DragonFly BSD forked from FreeBSD • OpenBSD forked from NetBSD Other •TUNIS (University of Toronto)
OBJECTIVE• To hide details of hardware by creating abstraction• To allocate resources to processes (manage resources)• Provide a pleasant and effective user interface• Convenience• Efficiency• Ability to evolve
SCOPEThe next-generation operating system starts with the user. Itignores the underlying hardware -- and as a result, such systemsare inherently less efficient than todays primitive, machine-centered ones. Instead, it reflects the shape of your life. Its role isto track your life event by event, moment by moment, thought bythought.A life is a sequence of events in time. The future of informationmanagement is narrative information management, in which allof your stored documents are arranged as a "documentaryhistory" of your life.
LEARNINGS ADVANTAGES OF OPERATING SYSTEM Windows• Openness to virus attacks is a major disadvantage.• Can be expensive, especially compared to Linux, which is in most cases free. Linux• It is an open source OS, which in most cases is free.• It is very reliable and rarely freezes. ADVANTAGES OF UNIX OPERATING SYSTEM• Virtual Memory• Toolbox• Customization• Portability
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