Sec 4. Chap 20 : Role of an operating system. Flashcards
Operating system.
An Operating System (OS) is an interface between a computer user and computer hardware. An operating system is a software which performs all the basic tasks like file management, memory management, process management, handling input and output, and controlling peripheral devices such as disk drives and printers.
Memory management. (OS)
Memory management is a form of resource management applied to computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed.
Processor Scheduling.
The practice uses the term “scheduling” because it assigns a specific percentage of time the processor is running to individual tasks. Processor scheduling is used to prevent specific tasks from monopolising all of a computer’s processor resources.
Schedular.
An OS module that ensures a processor is as efficient as possible. Their main task is to select the jobs to be submitted into the system and to decide which process to run. Provides acceptable response times.
Backing store management. (non-volatile)
OS’ keep a director of where files are stored so they can be quickly accessed when requested. OS ensures on harddisks that most common used applications are placed closer to the top.
OS also must understand which parts of the disk is used and which is free to be used.
Peripheral management.
Device management controls peripheral devices by sending them commands in their proprietary machine language. The software routine that deals with each device is called a “driver,” and the OS requires drivers for each of the peripherals attached to the computer.
Interrupt handling.
A signal usually sent from a peripheral device that the current execution must be paused (placed on a stack) and handled.
Because mid processes can be interrupted, it allows a new level of multitasking, on top of multicore processing.
