Operating Systems Questions

The perfect paging size varies from system to system, so there is no single best when it reaches to page size. There are several factors to consider in order to come up with a fitting page size, such as paging time, page table, and its effect on the total performance of the operating system.

Fragmentation occurs in a dynamic memory allocation system when many of the free blocks are too small to satisfy any request. 

External Fragmentation: External Fragmentation happens when a dynamic memory allocation algorithm allocates some memory and a small piece is left over that cannot be effectively used. If too much external fragmentation occurs, the amount of usable memory is drastically reduced. Total memory space exists to satisfy a request, but it is not contiguous. 

Internal Fragmentation: Internal fragmentation is the space wasted inside of allocated memory blocks because of restriction on the allowed sizes of allocated blocks. Allocated memory may be slightly larger than requested memory; this size difference is memory internal to a partition, but not being used

Dispatcher module gives control of the CPU to the process selected by the short-term scheduler; this involves: Switching context, Switching to user mode, Jumping to the proper location in the user program to restart that program, dispatch latency – time it takes for the dispatcher to stop one process and start another running.

A computer program is a collection of instructions that performs a specific task when executed by a computer

Cookies are small pieces of information that are stored in a browser. It keeps track of user preference, like what sites are visited, what keywords are used, among others.

1. Increased speed and memory capacity of microprocessors together with the support for virtual memory and

2. Growth of client server computing

All the above listed are the components of Windows registry

Getting the value of an environment variable is done by using `getenv()’. Setting the value of an environment variable is done by using `putenv()’