As we are aware of that, RAM serves astemporary storage and works space for the operating system. RAM isused in numerous other way. Virtual Memory Most modern operating systems employ a method of extending RAMcapacity, known as "virtual memory". A portion of thecomputer's hard drive is set aside for a paging file or a scratchpartition, and the combination of physical RAM and the paging fileform the system's total memory. (For example, if a computer has 2 GBof RAM and a 1 GB page file, the operating system has 3 GB totalmemory available to it.) When the system runs low on physical memory,it can "swap" portions of RAM to the paging file to makeroom for new data, as well as to read previously swapped informationback into RAM. Excessive use of this mechanism results in thrashingand generally hampers overall system performance, mainly because harddrives are far slower than RAM. [h=3]RAM disk[/h]Software can "partition" a portion of a computer's RAM,allowing it to act as a much faster hard drive that is called a RAMdisk. A RAM disk loses the stored data when the computer is shutdown, unless memory is arranged to have a standby battery source. [h=3]Shadow RAM[/h] Sometimes, the contents of a relativelyslow ROM chip are copied to read/write memory to allow for shorteraccess times. The ROM chip is then disabled while the initializedmemory locations are switched in on the same block of addresses(often write-protected). This process, sometimes called shadowing, isfairly common in both computers and embedded systems. As a common example, the BIOS in typical personal computers oftenhas an option called “use shadow BIOS†or similar. When enabled,functions relying on data from the BIOS’s ROM will instead use DRAMlocations (most can also toggle shadowing of video card ROM or otherROM sections). Depending on the system, this may not result inincreased performance, and may cause incompatibilities. For example,some hardware may be inaccessible to the operating system if shadowRAM is used. On some systems the benefit may be hypothetical becausethe BIOS is not used after booting in favor of direct hardwareaccess. Free memory is reduced by the size of the shadowed ROMs
MEMORY Memory refers to the amount of storage you have in your computer. We'll explore topics like RAM, caching and virtual memory. For example, a computer with 8MB RAM has approximately 8 million bytes of memory that programs can use. In contrast, ROM (read-only memory) refers to What is RAM and what does it do? RAM - Random Access Memory, or volatile memory, is used by the system to store data for processing by a computer's central The two main forms of modern RAM are Static Ram(SRAM) and dynamic RAm (DRAM). In static RAM, a bit of data is stored using the state of a flip- flop. Other uses of RAM Virtual memory Most modern operating systems employ a method of extending RAM capacity, known as "virtual memory". RAM disk Software can "partition" a portion of a computer's RAM, allowing it to act as a much faster hard drive that is called a Ram disk. Shadow RAM Sometimes, the contents of a relatively slow ROM chip are copied to read/write memory to allow for shorter access times.