NEC POWERMATE ES Series Service And Reference Manual page 120

I/O address
Input-Output address. How the CPU sees an I/O port. It puts data into this address or reads
the data in it. The device at the other end of the I/O port gets the data from that address or
puts the data there, respectively.
IRQ
Interrupt Request. A signal that, when received by the CPU, makes it stop what it is going
to do something else. An interrupt is a way in which a particular device in a computer
communicates with the CPU. PCs have 16 IRQ lines that can be assigned to different
devices (for example, printers, scanners, modems). No two devices can have the same IRQ
address. See interrupt.
ISA
Industry Standard Architecture. The bus architecture used in the IBM PC/XT and PC/AT.
The AT version of the bus is called the AT bus and has become an industry standard. The
apparent successor is the PCI local bus architecture found in most of today's computers.
Most modern computers include both an AT bus for slower devices and a PCI local bus for
devices that need better bus performance. In 1993, Intel and Microsoft introduced a new
version of the ISA specification called Plug and Play ISA. Plug and Play ISA enables the
operating system to configure expansion boards automatically so that users do not need to
fiddle with DIP switches and jumpers. See plug and play.
isochronous
A form of data transmission in which individual characters are only separated by a whole
number of bit-length intervals.
K
kilobyte
(KB) 1024 bytes.
L
L2 cache
Refers to "level 2" or "secondary" cache. A type of cache that resides on the motherboard
except when referring to a Pentium machine, where it resides on the CPU module.
LAN
Local Area Network.
LPT1
Name assigned to the parallel port by the Windows operating system. A second parallel
device is assigned LPT2 (if there is another parallel port). Also called the printer port.
M
master
Part of a two-sided communication that initiates commands (to a "slave" that carries out the
commands).
megabyte
(MB) 1,048,576 bytes.
Glossary 9