TYAN THUNDER I7522 Manual page 50

Thunder i7520 / Thunder i75 20 R Appendix I: Glossary
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.
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 t o buy a new chip. TYAN's BIOS updates can be found at
http://www. tyan.com
EMRL: Embedded RAID Logic. An Adaptec specific RAID technology.
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.
Form factor: an industry term for the size, shape, power supply type, and external connector
type of the Personal Computer Board (PCB) or motherboard. The standard form factors are
the AT and ATX, although TYAN also m akes some Baby -AT and ATX Footprint boards.
Global timer: onboard hardware timer, such as the Real -Time Clock (RTC).
Handshaking: a process where two devices initiate communications. One device, typically the
server, sends a message to another device, ty pically a client, in order to request establishment
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