AM3270/TR3271 Reference Manual

Glossary
Glossary–2 086705 Tandem Computers Incorporated
CCITT. Comité Consultatif International Télégraphique et Téléphonique (International
Telegraph and Telephone Consultative Committee). A standards-setting group for
international telephone carriers.
CIU . Communications Interface Unit. This is the proper term used for the 3650/6100
family of controllers. There can be two of these dual-ported, programmable I/O
controllers in each 6100 CSS or 3650 CSS; the CIUs connect the host with the rest of the
6100 CSS or 3650 CSS. These CIUs are another fault-tolerant Tandem enhancement: if
one of the CIUs fails, the other takes over.
CLB. CIU-to-LIU bus. A hardware component of the 6100 CSS and the 3650 CSS. It is
a cable with a dual, high-speed, full-duplex serial bus that connects the CIUs to the
rest of the 6100 or 3650 subsystem. See LIU.
CLIP. Communications Line Interface Processor. Part of the LIU within the 3650/6100
family of controllers, the CLIP is a programmable process that provides link-level
protocol and a software interface to the host. The CLIP does some of the work that
used to be handled by the host-resident communication processes. CLIP software
implements specific communication protocols, such as AM3270 or TR3271.
cluster controller. See TCC.
CMI. Communications Management Interface and its primary server process, the
Communications Management Process (CMP), provide one method to configure
existing controllers and to add new subdevices for lines controlled by either AM3270
or TR3271. CMI can also inquire about the characteristics and status of lines, though it
cannot add new lines. AM3270 and TR3271 do not support CMI for D-series releases.
CMP. Communications Management Process. See CMI.
CONFTEXT. The main configuration file that contains all the hardware descriptions
applicable to your Tandem system. This file is used for input by SYSGEN.
COUP. Configuration Utility Program. It allows online configuration of existing
controllers and lines without requiring a complete system generation process. COUP
is the user interface for DSC. COUP is different from CUP, the Communications
Utility Program. See also CUP, DSC.
CRC. Cyclic Redundancy Check. A method of detecting errors in a message by
performing a mathematical calculation upon the bits in the message, and then sending
the results when the message is sent. The same calculation at the receiving end must
derive matching results, or an error is produced.
CSM. Communications Subsystem Manager. A software process within the CPU that
coordinates certain functions within the 6100 subsystem. Among other things, the
CSM can load special microcode into the CIUs and CLIPs. The CSM also monitors the
physical environment of the 6100 CSS.
CTS. Clear to Send. A signal that comes from a modem, indicating to the computer
equipment that the modem is ready to accept data for transmission.