IBM 3745 Series Service Functions page 302

high-speed scanner. Line adapter for lines up to 2
million bps, composed of a communication scanner
processor (CSP) and a front-end high-speed scanner
(FESH).
high-speed transfer. A mode of high-speed data
transmission over an I/O interface to enable commu-
nication between data processing systems through a
channel.
hit. In cache operation, indicates that the information
is in the cache storage.
host processor.
(1) A processor that controls all or
part of a user application network. (2) In a network,
the processing unit in which the access method for
the network resides. (3) In an SNA network, the proc-
essing unit that contains a system services control
point (SSCP). (4) A processing unit that executes the
access method for attached communication control-
lers. Also called
host.
IBM service representative. An individual in .IBM who
performs maintenance services for IBM products or
systems.
initial microcode load (IML). The process of loading
the microcode into a scanner or into MOSS.
initial program load (IPL). The initialization procedure
that causes 3745 control program to commence oper-
ation.
input/output control (IOC). The circuit that controls
the input/output from/to the channel adapters and
scanners via the 10C bus.
internal clock function. A L1C function that provides a
transmit clock for sending data, and retrieves a
receive clock from received data, when the modem
does not provide those timing signals. When the ter-
minal is connected in direct-attach mode (without
modem) the ICF also provides the transmit and
receive clocks to the terminal, via the L1C card.
internal function test (1FT). A set of diagnostic pro-
grams designed and organized to detect and isolate a
malfunction.
L1C module. A group of four adjacent L1Cs.
LIC unit. A line interface coupler unit (L1U) consisting
of:
• One power supply (PS) associated with
• Two line interface boards (L1Bs), housing
• Multiplex cards (DMUX, SMUXA, or SMUXB), and
• Line interface coupler cards (L1Cs)
line. See
transmission line.
line adapter (LA). The part of the TSS, HPTSS, or
TRSS that scans and controls the transmission lines.
Also called
scanner.
For the TSS the line adapters are low-speed scanners
(LSSs).
For the HPTSS the line adapters are high-speed scan-
ners (HSSs).
For the TRSS the line adapters are token-ring
adapters (TRAs).
line interface coupler (L1C). A circuit that attaches up
to four transmission cables to the controller.
Link Problem Determination Aid (LPDA). A set of test
facilities resident in the IBM 386X/586X modems and
activated from the control program in the controller
and from host.
link protocol. The set of rules by which a logical data
link is established, maintained, and terminated, and
by which data is transferred across the link.
Logrec. Error logging program managed via the
operating system.
longitudinal redundancy check (LRC). A system of
error checking performed at the receiving station
after a block check character has been accumulated.
low-speed scanner. Line adapter for lines up to 256
kbps, composed of a communication scanner
processor (CSP) and a front-end low-speed scanner
(FESL).
maintenance and operator subsystem (MOSS). The
part of the controller that provides operating and ser-
vicing facilities to the customer's operator and the
IBM service representative.
microcode. A program, that is loaded in a processor
(for example, the MOSS processor) to replace a hard-
ware function. The microcode is not accessible to the
customer.
miss. In cache operation, indicates that the informa-
tion is not in the cache storage.
modem (modulator-demodulator). A functional unit
that transforms logical signals from a DTE into analog
signals suitable for transmission over telephone lines
(modulation), and conversely (demodulation). A
modem is a DCE. It may be integrated in the DTE.
MOSS input/output control (MIOC). The circuit that
controls the input/output from/to the MOSS.
multiplexer channel. A channel designed to operate
with a number of I/O devices simultaneously. Several
I/O devices can transfer records at the same time by
Glossary
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