In computer operating systems that have their main memory divided into pages, paging (sometimes called swapping) is a transfer of pages between main memory and an auxiliary store, such as hard disk drive.[1] Paging is an important part of virtual memory implementation in most contemporary general-purpose operating systems, allowing them to use disk storage for data that does not fit into physical RAM. Paging is usually implemented as architecture-specific code built into the kernel of the operating system.
Segmentation:
Segmentation is one approach to memory management and protection in the operating system. It has been superseded by paging for most purposes, but much of the terminology of segmentation is still used, "segmentation fault" being an example. Some operating systems still have segmentation at some logical level although paging is used as the main memory management policy.
Paging:-
Paging is a memory-management scheme which allow the physical address of a process to be non-contiguous.
The basic implementation of paging involves breaking physical memory in fixed sized blocks called frame and breaking logical address (generated by CU) in fixed sized blocks called page. Usually page size and frame size is same. Every address generated by CPU is divided into two parts a) page number(p) and page offset(d). The page table is used a index in the page table. The page table contains the base address of each page in physical memory. This base address combines with the page offset (d) to locate the space in the physical memory.
This is simply what the paging is all about.......!!
And about the how the page number and page offset is divided and used in the determination of physical address and page table you should consult any good book.......
Thank you...
thev777@gmail.com
Paging occurs when the operating system swaps the contents of a portion of active memory (RAM) with an image of another portion of active memory that was written to disk (in the page file). Using this technique the operating system is able to run programs that require more memory (RAM) than actually exists in the hardware of the computer.
Thrashing
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.
thrashing
The question is not very clear - in general the implementation of paging is too complex to answer in a Wiki answer entry; I suggest you take a look at any Operating System theory book.
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.
Any operating system that allows for "paging" or "swapping" is capable of this.
"Paging" is when the operating system writes contents of RAM memory to disk, to free space for other uses.A paging algorithm specifies which RAM content to page (write to disk) when it needs more space.See related link.
Paging has many advantages. First of all, paging allows you to relocate memory areas to other places where they are more useful. For example, any operating system must divide memory in two areas, one for the operating system itself (OS, data, management tables, ...) and one for the user programs. The area for the OS must be subdivided into areas to store each driver and its data. The area for the user must be subdivided to store each program and its data.
The best paging system is Wendy's drive thru
Some Operating Systems periodically look for pages that have not been recently referenced and add them to the Free page queue, after paging them out if they have been modified.
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.
Paging is a way for the operating system to load data from a storage device onto RAM. When there is insufficient amount of space in RAM and if a page file is enabled, it will swap data between RAM and the swap file (typically on a storage device).