A Glossary for 386
BUS SPEED: Modems, disk drives and facsimile boards connected to a bus generally operate at 10 MHz or less. In contrast, an 80386 CPU's clock speed goes as high as 33 MHz.
CACHE: Dedicated memory area that buffers data or instructions ready for use.
CACHING CONTROLLER: Massive buffer with up to several megabytes of dedicated RAM to improve hard-disk access time.
DIP: Dual in-line package, the traditional bug-like integrated circuit chip.
DRAM: Dynamic random-access memory chip.
FCC RATING: Measure of radio-frequency interference from circuitry signals. Class A is for office computers. Class B indicates a better-shielded machine for use near radios and televisions.
INTERLEAVED MEMORY: Identical data in two different memory banks. One always remains available while the other is being refreshed.
MEMORY CACHE: Portion of memory set aside and not subtracted from the 640K that holds the next instructions or data for the CPU; controlled by dedicated chip or software.
PROTECTED MODE, 286: 16-bit operating mode that assists multitasking and consumes up to 16M RAM. An 80286 computer in protected mode can run only one MS-DOS program under OS/2.
PROTECTED MODE, 386: A 386 chip can address up to four gigabytes of memory by switching into 32-bit internal operation. Few applications need more than 16M.
REAL 8086 MODE: Start-up operating mode of 8086/88, 286 and 386 computers.
RFI: Radio-frequency interference emitted by a poorly shielded computer or external device such as a hard disk.
SHADOW RAM: Software that loads the 16-bit system or video BIOS from a chip on the motherboard into faster 32-bit RAM upon power-up.
SIMM: Single in-line memory module carrying many memory chips.
SIP: Single in-line package. Integrated circuit chip with all leads coming off one side.
SRAM: Static random-access memory chip. Faster and costlier than DRAM.
TEMPEST: The ultimate RFI rating. A Tempest computer radiates no electro-magnetic signals that might be intercepted remotely.
VIRTUAL 8086 OPERATION: An 80386 chip can set aside memory to run programs on a simple, 8086-like virtual computer. That is how 386 UNIX operating systems run PC-compatible programs.