IBM System/370 Operator's Reference Manual page 234

CCW (channel command word): A double word at the location in main storage speci-
fied by the CAW_ One or more CCWs make up the channel program that directs
channel operations_
CE pack: A disk pack used to test an IBM 2314, or 3330_ It has an RO data length
of 6 at any location other than cylinder
0,
track
0_
CE volume: If the device is a 2314 or 3330, see CE pack_
channel: A hardware device that connects the CPU and main storage with the 1/0
control units.
channel program: One or more Channel Command Words (CCWs) that control(s) a
specific sequence of channel operations. Execution of the specific sequence is initiated
by a single start 1/0 instruction.
channel program translation: In a channel program, replacement, by software, of virtual
addresses with real addresses.
ell: Core Image Library.
command control block (ceB): Under DOS and TOS, a 16-byte field required for each
channel program executed by physical 10CS. This field is used for communication
between physical 10CS and the problem program.
connnunication region: Under DOS and TOS, an area of the supervisor set aside for
interprogram and intraprogram communication. It contains information useful to both
the supetvisor and the problem program. Abbreviated comreg. (Not to be confused
with the COMRG macro instruction)_
communications interval: A period of communication between the console operator
and Ol TEP. The operator is requested by Ol TEP to enter the test-run definition at
this time_
concatenated data
set:
A group of logically connected data sets.
Configuration Data Set (CDS): A record of information about an 1/0 device or CPU
ilCccs::;cd by CL TEP ui"id the CL T.
control blocks: A storage area used by the operating system to hold control in-
formation.
control dictionary: The external symbol dictionary and relocation dictionary, collec-
tively, of an object or load modu Ie.
control program: The routines in the operating system that manage resources, im·
p lement data organization and communications conventions, or contain privileged
operations.
control registers: In S/370, a set of registers used for operating system control of
relocation, priority interruption, program event recording, error recovery, and masking
operations.
control section: That part of a program specified by the programmer to be a re-
locatable unit, all of which is to
be
loaded into adjoining main storage locations.
control volume: A volume that contains one or more indexes of the catalog.
core-wrap mode: The method of operation that records the events of a trace ic the
PD area or an alternate area (used by PDAIDS)' It is the default process
whe~
no
output device for a PDAID trace has been specified.
CPU (central processing unit): The unit of a system that contains the circuits that
control and perform the execution of instructions.
CRT (Cathode Ray Tube): Visual Display Screen.
CSW (channel status word): A word in main storage at location 64 that orovides
information about the termination of an input/output ooeration.
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