OPERATING SYSTEM

Exercises:

research topic:

Unit name - absolute size - exponential form
byte - 1 byte -2
kilobyte -1,024 byte -2^10
megabyte -1,048,576 bytes -2^20
gigabyte -1,073,741 bytes -2^30
terabyte -1,099,511,627,776 -2^40
petabyte -1,125,899,906,824,624 -2^50

Exercises:
A.Explain he following:
Multiprogramming. Why i s it used? A multiprogramming is a technique used to utilize maximum CPU time by running multiple programs simultaneously. The execution begins with the first program and continuous till an instruction waiting for a peripheral is reached, the context of this program is stored, and the second program is memory is given chance to run. The process continued until all program finished running. Multiprogramming has no guarantee that a program will run is timely manner.
B.Internal Fagmentation. How does it occur? The internal fragmentation occurs it when a fixed
partition is partially used by program, the remaining space within the partition is unavailable to any other job and that's the time internal fragmentation occur when there is another job followed on the space. So that it will not wasted.
C.Compaction: Why is it need? Compaction is very needed because it is the process of collecting fragments of available memory space into contiguous in block by moving programs and data in a
computer's memory disks, or known as garbage collection.
E.Relocation: How often should it performed? It depend on the process of address refferences in program.
#2. Describe the Major Disadvantages for each of the four memory allocation schemes presented in the chapter. The disadvantage of this memory allocation its an overhead process, so that while compaction is being done everything else must wait.
#3.Describe the Major Advantages for each of the memory alloatiuon schemes presented in the chapter. They could be divided into segments of variable sizes of equal size. Each page, or segment, could be stored wherever there was an empty block best enough to hold it.