Assignment: Noncontiguous Memory Allocation In Memory Management System

MEMORY MANAGEMENT UNIT

Special Assignment(Term Paper)

HIMANSHU RATHOD (13BEC176)

Electronics & Communication Engineering Institute of Technology Nirma University [e-mail] ABSTACT:-

In memory management unit we have limited memory so we used virtual memory. Mapping is between pages and frames. Mapping is done by MMU. Processor after dividing the program into pages generates virtual address. Through this mapping we received virtual address of page and by mapping generates the physical address of the frame so we can read the program and execute it.so large program can be executed in small memory.

Keywords: MMU;

We can use any address because there is no gaps and no holes in it. In static memory allocation OS defines memory to process in sequence for faster regeneration.

In contiguous memory location the problem we have space but it is not in contiguous so we cannot allocate to a process. This is known as external fragmentation. Operating system allocates memory dynamically not in sequence this operation is known as Noncontiguous Memory Allocation. When process does not required in memory so it released from memory so there will be Memory hole. So memory hole will filled with another required process. We can overcome the problem of external fragmentation by using dynamic storage allocation. Rearrange processes to minimize external fragmentation so the base registers and address spaces will be

The technique we used in compaction is swaping.in swapping there are two types of relocation:

• Static relocation-code or data return to the same place

• Dynamic relocation-new position at memory has to find out by memory.

Contiguous memory

In contiguous memory mapping translates contiguous physical address to contiguous virtual address. The problem is in contiguous is external fragmentation and sharing between memories is difficult

Virtual memory

German physicist Fritz-Rudolf developed the concept of virtual memory. In discontiguous physical address we are breaking the virtual address space into small chunks it is called virtual memory. Lack space of memory to fit the program so OS will take the part of the program which is currently execute in the memory. We splits the main program into pieces it is called overlays but we have to too much too work.so we used virtual memory. We can implement virtual memory by segmentation and paging. Virtual address is generated by CPU. We can run large program in limited memory space. Mapping is the heart of virtual memory.

For security and reliability by providing virtual address