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Demand paging and Demand segmentation are both ways to implement the" virtual memory scheme" to enhance the multitasking abilities of the OS with respect to the 2 the memory management schemes : paging and segmentation.
Where demand paging means, bringing a fixed-sized block of memory, known as a frame, from the backing store to the main memory, the demand segmentation is the same for a whole big segment of data, which might have any size(not predefined, not pre-known to OS).!
Page demanding happens when an application requests for a page that does not exist on the main memory, but is illusioned to be there by the virtual memory .In this case, an unavoidable system call "trap" demands for this page to be fetched from the backing store to be stored in one of the free memory locations in the memory (if possible) OR replace it with any other page in it according to the Page replacement algorithm being used. Now, since pages are fixed-sized blocks of memory, then the case of Page replacement is easy since it is known that 1 page (fixed size memory-block) needs to be replaced for this page to be accommodated. But in case of segments, since they are of variable sizes (maybe larger (often) or smaller than a general page-size), it is difficult to create a space for it in the main memory. The Segment replacement algorithm in that case would be a bit cumbersome and less efficient to optimally create an appropriate-sized memory block for this segment to be fetched from the backing store into the main memory.
Also, a problem (very low probability) might occur where the segment size is too large for the physical memory to accommodate.
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What is difference between demand paging n pure demand paging?
In demand paging, a page is not loaded into main memory until it is needed. In pure demand paging, even a single page is not loaded into memory initially. Hence pure demand paging causes a page fault. Page fault, the situation in which the page is not available whenever a processor needs to execute it.
What difference between paging?
Difference between paging and what?
How Intel Pentium supports segmentation and paging?
The Intel Pentium supports pure segmentation and segmentation with paging. The processor creates logical addresses, which are mapped to physical addresses by the segmentation unit. Those addresses may point to physical addresses within memory or paged swap space.
What is a Difference between default paging and custom paging?
Default paging is what it already comes with. It is a pre-made template, while custom paging would be ones on ideas and creativity.
What are the differences between simple paging and virtual memory paging?
In case of simple paging all pages should be in main memory to run a process..while in case of virtual memory paging pages can be loaded as needed by the processor i.e. called demand paging...
What is difference between paging and swapping?
Nothing -- they are the same thing.
Explain how virtual memory system using demand paging?
Demand paging is a process which involves the copying and relocation of data from a secondary storage system to random access memory (RAM), a main memory storage system. Demand paging copies and relocates data to facilitate the fastest access to that data. Once the data is relocated, demand paging sends a command to the operating system to inform it that the data file or files are now ready to be loaded. Demand paging is performed on demand, or after a command has been sent to retrieve specific data.
The technique of swapping items between memory and storage?
It is paging.
Why paging is faster than segmentation?
Paging is a technique with the help of which we can divide the memory into pages which help us to easly access the files and it also decreases the Execution time (Saves SYSTEM time). It also creates a mirage of Memory.
What is the Difference between paging and demand paging in operating system?
paging is the process of memory management in which memory is allocated in the non contiguous form,i.e. the program is break into block of fixed size known as page and also the main memory also break down into block of same size known as frame or page frame. Now all this page are brought into the main memory but in the space available so they can be contiguous if they find whole space required by the program or if the space is available but in scattered form then they can give space in non contiguous form. But in demand paging only those pages are brought into main memory which are required to execute the program at that time when a program need other pages it will swap out the unused pages from the main memory and swap in the desired page thus allowing it to execute the program though the space available is not sufficient to bring the whole program into main memory..................One of the problem arises due to demand paging is page fault which is caused due to required page not found in main memory for which we require swapping. hey if you like my post don't forget to thank me....... for any further queries e-mail me at hemant_spidey3@yahoo.co.in or 1989hemantrajput@gmail.com
What is a memory characteristic where an application can request a specific item from memory?
Demand Paging
Compare paging with segmentation with respect to the amount of memory required by the address translation structures in order to convert virtual addresses to physical addresses?
Paging requires more memory overhead to maintain the translation structures. Segmentation requires just two registers per segment: one to maintain the base of the segment and the other to maintain the extent of the segment. Paging on the other hand requires one entry per page, and this entry provides the physical address in which the page is located.
