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Appendix 3
Glossary
cached. However, only 512KB of this memory will be in the cache at any given
moment. Any main memory above 512MB could never be cached.
Closed and open jumpers Jumpers and jumper pins are active when they are
On or Closed, and inactive when they are Off or Open.
CMOS Complementary Metal-Oxide Semiconductors are chips that hold the
basic start-up information for the BIOS.
The COM port is another name for the serial port, which is so-called because it
transmits the eight bits of a byte of data along one wire, and receives data on
another single wire (that is, the data is transmitted in serial form, one bit after
another). Parallel ports transmit the bits of a byte on eight different wires at the
same time (that is, in parallel form, eight bits at the same time).
DIMM Dual In-line Memory Modules are a faster and more capacious form of
RAM than SIMMs, and do not need to be installed in pairs.
DIMM bank DIMM banks are sometimes called DIMM sockets, because the
physical slot and the logical unit are the same. That is, one DIMM module fits
into one DIMM socket, which is capable of acting as a memory bank.
DMA Direct Memory Access channels are similar to IRQs. DMA channels allow
hardware devices (like sound cards or keyboards) to access the main memory
without involving the CPU. This frees up CPU resources for other tasks. As
with IRQs, it is vital that you do not double up devices on a single line. Plug
and Play devices will take care of this for you.
In Doze mode, only the CPU’s speed is slowed.
DRAM Dynamic RAM is a widely available, very affordable form of RAM
which has the unfortunate tendency to lose data if it is not recharged regularly
(every few milliseconds). This refresh requirement makes DRAM slower three
to ten times slower than non-recharged RAM such as SRAM.
EDO RAM (Extended Data-Out RAM) speeds access to memory locations by
assuming that memory addresses are static: the next time it looks for a bit of
data, it will be at the same spot, or one nearby.
EEPROM Electrically Erasable Programmable ROM, also called Flash BIOS, is a
