| | | | Random Access Memory. Solid state storage medium taking the form of a number of integrated circuits (ICs) or silicon chips, mounted on PCBs (Printed Circuit Boards). Ordinarily RAM is not mounted permanently on the motherboard of a personal computer but is installed separately in a number of discrete slots. The exception of this is the memory associated directly with the processor or "cache", which is onboard the CPU (central processing unit) itself. Data storage in RAM is short-term in that it is only held there as long as there is power to the computer. When the power is turned off it is lost, in contrast to long-term storage media such as ROM (Read Only Memory), magnetic HDDs (hard disk drives), optical disks and magnetic tape media. RAM is "random access" because data stored can be accessed in any order, not just sequentially, and with no relationship necessary between one piece of data and the next. Access time is not related to the physical position of the data because there are no moving parts, unlike other storage media such as tapes and hard disk drives where mechanical movement is required, which is the slowest part of the access procudure. Because of it's speed, RAM is used as primary storage for applications currently in use (including the operating system), data being handled and images to be displayed. In most common usage, RAM refers generally to DRAM, or Dynamic RAM, so called because it needs to be refreshed thousands of times per second. Unlike other storage media, when "full" RAM is still able to handle more data, however in order to do this the processor must continually go back and forth to other media (normally a hard drive) in order to use "virtual memory" (an area set aside on the hard drive for this purpose) so that it can overlay new data over old in the RAM. This greatly slows down the running of the computer and is often an indicator that more RAM should be installed. | | | |
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