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segmentation

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ramya marichamy

The document discusses memory management techniques including paging and segmentation. Paging divides programs into fixed-size pages which are loaded into main memory frames on demand. Segmentation divides programs into logical segments that can grow independently. Virtual memory uses the hard disk to simulate additional RAM by paging segments between disk and main memory. The operating system manages virtual memory using policies for when pages are fetched from disk to memory and replaced in memory.

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PRESENTED BY S.NANDHINI I- M.sc(CS&IT) NADAR SARASWATHI COLLEGE OF ARTS & SCIENCE. VADAPUDUPATTI , THENI.
Memory management scheme that supports user view of memory. A program is a collection of segments. A segment is a logical unit such as Main program,procedure,function. Local variable,global variable.
segmentation
Paging is transparent to the programmer. Paging eliminates external fragmentation. Segmentation is visible to the programmer. Segmentation allows for growing data structures,modularity,and support for sharing and protection. Each segment is broken into fixed size pages. The segment entry points to a page table for that segment.
segmentation
segmentation
o A method of using hard disk space to provide extra memory. o It simulates additional RAM. o An address used by a programmer will be called a virtual address ,and set such addresses the address space. o An address in main memory is called a location or physical address and the set of such address is called memory space.
segmentation
An operating system or os is a software program that enables the computer hardware. To communicate and operate with the computer software without a computer operating system. A computer and software programs would be useless.
When to fetch the page from auxiliary memory to main memory. 2 Approaches: Demand paging only brings pages into main memory when a reference is made to a location on the page. Prepaging brings in pages whose use is anticipated.
Not all pages in main memory can be selected for replacement. Some frames are locked(cannot be paged out)
Resident set:. Set of a process pages which are in main memory. Os must manage the size and allocation policies which effect the resident set.
segmentation

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segmentation

  • 1. PRESENTED BY S.NANDHINI I- M.sc(CS&IT) NADAR SARASWATHI COLLEGE OF ARTS & SCIENCE. VADAPUDUPATTI , THENI.
  • 2. Memory management scheme that supports user view of memory. A program is a collection of segments. A segment is a logical unit such as Main program,procedure,function. Local variable,global variable.
  • 4. Paging is transparent to the programmer. Paging eliminates external fragmentation. Segmentation is visible to the programmer. Segmentation allows for growing data structures,modularity,and support for sharing and protection. Each segment is broken into fixed size pages. The segment entry points to a page table for that segment.
  • 7. o A method of using hard disk space to provide extra memory. o It simulates additional RAM. o An address used by a programmer will be called a virtual address ,and set such addresses the address space. o An address in main memory is called a location or physical address and the set of such address is called memory space.
  • 9. An operating system or os is a software program that enables the computer hardware. To communicate and operate with the computer software without a computer operating system. A computer and software programs would be useless.
  • 10. When to fetch the page from auxiliary memory to main memory. 2 Approaches: Demand paging only brings pages into main memory when a reference is made to a location on the page. Prepaging brings in pages whose use is anticipated.
  • 11. Not all pages in main memory can be selected for replacement. Some frames are locked(cannot be paged out)
  • 12. Resident set:. Set of a process pages which are in main memory. Os must manage the size and allocation policies which effect the resident set.