Author: GuruKPO

Operating system is an intermediary between computer user and computer hardware, it acts as an interface between user and hardware. It resides in upper portion of main memory and works in privileged mode. Functions of OS are: file management, memory management, device management and process management. Goal of OS are: convenience (eg. Windows OS) and efficiency (eg. Unix). Generations of OS are: 1.sequential,
2.Batch,
3.Multiproggramming,
4.Real time OS.

Contiguous memory believes in storing data in continuous locations. It is the largest chuck of available memory that is not fragmented. When a process needs to execute, memory is requested by the process. The size of the process is compared with the amount of contiguous main memory available to execute the process. If sufficient contiguous memory is found, the process is allocated memory to start its execution. Otherwise, it is added to a queue of waiting processes until sufficient free contiguous memory is available.