a2zinterviews

1.	What is an operating system?
	An operating system is a program that acts as an intermediary between the user and the computer hardware. The purpose of an OS is to provide a convenient environment in which user can execute programs in a convenient and efficient manner. It is a resource allocator responsible for allocating system resources and a control program which controls the operation of the computer hardware.

2.	Why paging is used?
	Paging is solution to external fragmentation problem which is to permit the logical address space of a process to be noncontiguous, thus allowing a process to be allocating physical memory wherever the latter is available.

3.	Explain the concept of the batched operating systems?
	In batched operating system the users gives their jobs to the operator who sorts the programs according to their requirements and executes them. This is time consuming but makes the CPU busy all the time.

4.	What is purpose of different operating systems?
	The machine purpose workstation individual usability &resources utilization mainframe optimize utilization of hardware PC support complex games, business application Hand held PCs Easy interface & min. power consumption.

5.	What is virtual memory?
	Virtual memory is hardware technique where the system appears to have more memory that it actually does. This is done by time–sharing, the physical memory and storage parts of the memory one disk when they are not actively being used.