Power computing glossary. (Compute's Getting Started with Power Computing) (Glossary)
by David English

conventional memory. The first 640K of memory. It can be used by DOS without special programs or drivers. DIP. Short for Dual Inline Package. A memory-chip housing with metal pins that are inserted into circuit-board sockets.

DRAM. Short for Dynamic Random Access Memory. A type of computer memory that can hold information for only a short period of time. To maintain its contents, a DRAM chip needs to be refreshed with an electric charge hundreds of times a second.

EMS. Short for Expanded Memory Specification. A technique developed by Lotus, Intel, and Microsoft that allows 8088, 8086, 80286, 80386, and 80486-based systems to access more than 640K. The most common versions are the first-generation EMS 3.2 and the third-generation LIM 4.2. See expanded memory.

expanded memory. Memory that conforms to either the EMS or later EEMS standard. Specially written programs can, use an Expanded Memory Manager to access as much as 32 megabytes of expanded memory.

extended memory. Memory that can be used by 80286, 80386, and 80486-based systems. Programs must be specially written to use extended memory. With a memory-management program, 80386 and 80486 systems can use extended memory to simulate expanded memory.

kilobyte. A unit of measurement for computer memory and data storage that equals roughly one thousand bytes (actually 1,024 bytes). Abbreviated as K.

megabyte. A unit of measurement for computer memory and data storage that equals roughly one million bytes or one thousand kilobytes (actually 1,048,576 bytes or 1,024 kilobytes). Abbreviated as MB or M.

nanosecond. Used to measure memory chip speed. One billionth of a second.

RAM. Short for Random Access Memory. This kind of memory can be changed by a computer's programs, but whose contents usually disappear when the power is turned off.

RAM disk. A portion of memory that's set aside to simulate a disk drive. Though faster than a mechanical drive, its contents are lost when the computer is switched off. Also known as a RAM drive, virtual disk, or electronic disk.

resolution. The number of dots, or pixels, on the screen. The more pixels, the sharper the image. VGA can display 640 pixels horizontally by 480 pixels vertically.

ROM. Short for Read Only Memory. This kind of memory can' the changed by your computer's programs. A ROM chip's information is permanently recorded, so it isn't lost when your computer's power is turned off.

SIMM. Short for Single Inline Memory Module. A type of compact printed circuit board that holds multiple memory chips. Similar, but incompatible, memory-chip packages include the SIP Single Inline Package) and the SIPP (Single Inline Pin Package).

SRAM. Short for Static Random Access Memory. A type of memory that can hold information only a short period of time. Because it doesn't have to be refreshed as often with an electric charge, SRAM is usually faster than DRAM.

24-bit color. A method of storing and displaying computer-based graphics that allows 16,777,216 colors to be shown at a time.

virtual memory. A technique that simulates additional memory. Virtual memory usually spools part of a computer's contents to a disk drive so several programs can run at once.