tailieunhanh - Lecture Operating system concepts - Module 21

After studying this chapter, you should be able to: 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. | Module 21: The Unix System History Design Principles Programmer Interface User Interface Process Management Memory Management File System I/O System Interprocess Communication Operating System Concepts History First developed in 1969 by Ken Thompson and Dennis Ritchie of the Research Group at Bell Laboratories; incorporated features of other operating systems, especially MULTICS. The third version was written in C, which was developed at Bell Labs specifically to support UNIX. The most influential of the non-Bell Labs and non-AT&T UNIX development groups — University of California at Berkeley (Berkeley Software Distributions). 4BSD UNIX resulted from DARPA funding to develop a standard UNIX system for government use. Developed for the VAX, is one of the most influential versions, and has been ported to many other platforms. Several standardization projects seek to consolidate the variant flavors of UNIX leading to one programming interface to UNIX. Operating System Concepts . | Module 21: The Unix System History Design Principles Programmer Interface User Interface Process Management Memory Management File System I/O System Interprocess Communication Operating System Concepts History First developed in 1969 by Ken Thompson and Dennis Ritchie of the Research Group at Bell Laboratories; incorporated features of other operating systems, especially MULTICS. The third version was written in C, which was developed at Bell Labs specifically to support UNIX. The most influential of the non-Bell Labs and non-AT&T UNIX development groups — University of California at Berkeley (Berkeley Software Distributions). 4BSD UNIX resulted from DARPA funding to develop a standard UNIX system for government use. Developed for the VAX, is one of the most influential versions, and has been ported to many other platforms. Several standardization projects seek to consolidate the variant flavors of UNIX leading to one programming interface to UNIX. Operating System Concepts History of UNIX Versions Operating System Concepts Early Advantages of UNIX Written in a high-level language. Distributed in source form. Provided powerful operating-system primitives on an inexpensive platform. Small size, modular, clean design. Operating System Concepts UNIX Design Principles Designed to be a time-sharing system. Has a simple standard user interface (shell) that can be replaced. File system with multilevel tree-structured directories. Files are supported by the kernel as unstructured sequences of bytes. Supports multiple processes; a process can easily create new processes. High priority given to making system interactive, and providing facilities for program development. Operating System Concepts Programmer Interface Kernel: everything below the system-call interface and above the physical hardware. Provides file system, CPU scheduling, memory management, and other OS functions through system calls. Systems programs: use the kernel-supported system calls to provide .