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Cache size

: refers to the physical size of the cache onboard. This should not be confused with

the cacheable area, which is the total amount of memory which can be scanned by the system in
search of data to put into the cache. A typical setup would be a cache size of 512KB, and a
cacheable area of 512MB. In this case, up to 512KB of the main memory onboard is capable of
being 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):

chips that hold the basic startup

information for the BIOS.

COM port:

another name for the serial port, which is called as such 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).

DDR (Double Data Rate):

is a technology designed to double the clock speed of the memory. It

activates output on both the rising and falling edge of the system clock rather than on just the
rising edge, potentially doubling output.

DIMM (Dual In-line Memory Module):

faster and more capacious form of RAM than SIMMs, and

do not need to be installed in pairs.

DIMM bank:

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 that are similar to IRQs. DMA channels allow hardware

devices (like soundcards 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-n-Play devices will take care of this for you.

Doze mode:

in this mode, only the CPU’s speed is slowed.

DRAM (Dynamic RAM): 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 three to ten times slower than non-recharged RAM such as SRAM.

ECC (Error Correction Code or Error Checking and Correcting):

allows data to be checked for

errors during run-time. Errors can subsequently be corrected at the same time that they’re found.

EEPROM (Electrically Erasable Programmable ROM):

also called Flash BIOS, is a ROM chip

which can, unlike normal ROM, be updated. This allows you to keep up with changes in the BIOS
programs without having to buy a new chip. TYAN’s BIOS updates can be found at
http://www.TYAN.com

ESCD (Extended System Configuration Data):

a format for storing information about Plug-n-

Play devices in the system BIOS. This information helps properly configure the system each time
it boots.

Fault-tolerance:

a term describing a system where one component can quickly be replaced

without causing a loss of service, such as in a RAID system.

Firmware:

low-level software that controls the system hardware.