Operating System - Piece of software, the portion of the computing system that manages all of the hardware and all of the other software Major components of Operating Systems (Resources)
1. Memory manager – also known as RAM, primary memory. it allocates a portion of memory that isn’t already in use. It also deallocates memory when time comes to reclaim it. 2. Processor manager - decides how to allocate the CPU. Keep track the status of each process. Process – an instance of execution of a program.
Processor manager has two levels of responsibility.
a. As Job scheduler, a high-level portion of the processor manager which accepts or rejects the incoming jobs. b. As Process scheduler – a low-level portion of the processor manager which is responsible for deciding which process gets the CPU and for how long. 3. Device manager - monitors every device, channel and control unit. Its job is to choose the most efficient way to allocate all of the system’s devices, printers, ports, disk drives and other peripherals attached to the hardware based on a scheduling policy chosen by the system designer. 4. File manager – keep track of every file in the system, including data, files, program files, compilers and applications. The file manager also controls what users are allowed to do with files once they access them. 5. Network manager - provides a convenient way for users to share resources while controlling users’ access to them. Resources include hardware (CPU, memory area, printers, drives, modem) and software (compilers, application programs and data files).
Brief History of Machine Hardware
a. Mainframe – historical name given to a large computer system characterized by its large size, high cost and high performance. b. Minicomputer – developed to meet the needs of the smaller institutions. c. Supercomputer – fastest, most sophisticated computers made, used for complex calculations at the fastest speed permitted by...
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