Classification of memory allocation method(OS-6)

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memory allocation techniques

memory allocation techniques is two types : 
                                                                       1. continuous memory allocation
                                                                       2.non-continuous memory allocation

Continuous memory allocation:

-In this memory allocation all available memory space remain together. It means freely available memory partition are not scatter here.Their across the whole memory space.
-when any user process request for the memory a single section of the continuous memory block is given to the process according to its need.we can achieve the continuous memory allocation by dividing memory into the fixed sized.
-A single process is allocated into the fixed sized single partition but this will increase the degree of the multi programming means move than one process in the main memory that bounds the number of fixed partition done in memory international fragmentation increase because of the continuous memory allocation.

Fixed sized partition:

In the fixed sized partition the system divided memory into the fixed sized partition here. Enter partition is allowed to a process and if there is some wastage inside the partition is allocated to a process and if there is some wastage inside the partition that is called international fragmentation.

Variable sized partition :

In the variable sized partition the memory is treated as one unit and space allocated to a process is exactly same as required and the leftover space can reuse again.

Non -continuous memory allocation:

-In this memory allocation the available free memory space are scatter here and the all available memory space is not at one place so this is time consuming.
-A process will require the memory space but it is not at one place it is at the different location according to process requirement.
-These techniques reduces the wastage of memory which leads the internal or external  fragmentation.
-Non continuous memory allocation is three types
                                                                                 1.Paging
                                                                                 2.Segmentation
                                                                                 3.segmentation of paging

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