Chapter 12 – Operating Systems

Publisher Summary Systems programs control the operation of the computer. Applications programs instruct the computer how to handle an organization's information-processing needs. Systems programmers require an understanding of the internal operation of computer hardware. Applications programmers must understand the information-processing needs of an organization, and how computers might be used to meet those needs. Operating systems are collections of systems programs that allow computer systems to handle many functions previously performed by computer operators. Operating systems are primarily resource managers. They manage hardware, programs, and data. They assign hardware to users, charge for resource usage, run many users efficiently, and guarantee good service to users. Scheduling is one of the most important functions of an operating system. Priority scheduling ensures that the more important jobs are serviced first. User jobs are classified as batch processing, interactive, or real-time. Multiprogramming operating systems allow many jobs to run simultaneously. Storage protection mechanisms help to prevent programs from interfering with one another. Boundary registers prevent programs from accessing a storage address outside the range indicated by the registers.