byte-multiplexer channel 13-4,13-30 byte-oriented-operand facility 3-5
C
C (COMPARE) binary instruction 7-12
cache 3-2
CAr (channel-available interruption)
13-29,13-61
carry 7-3
CAW (channel-address word) 13-37
assigned storage locations for 3-42
in IPl 4-36
CBC (checking-block code) 11-2
invalid 11-2
in registers 11-9
in storage 11-6
in storage keys 11-7
near-valid 11-2
valid 11-2
CC (chain-command) flag in CCW
13-7,13-38
CCW (channel-command word) 13-38
address of in CAW 13-37
address of in CSW 13-63
contents of 13-75
validity flag for 13-82
chaining of 13-40 commands (See command chaining of
cews)
data (See data chaining of CCWs)
command codes (See commands)
command retry of 13-53
count field in (See count field)
data-address field in 13-39
flags in 13-49
format of 13-38
in rPl 4-36
assigned storage locations for
3-41
prefetching of 13-40,13-42 role of in I/O operations 13-5
CD (chain-data) flag in CCW 13-6,13-38
CD (COMPARE) floating-point instruction
9-8
CDR (COMPARE) floating-point instruction
9-8
examples A-37
CDS (COMPARE DOUBLE AND SWAP) instruc­
tion 7-12
examples A-40 CE (COMPARE) floating-point instruction
9-8
central processing unit (See CPU) CER (COMPARE) floating-point instruction
9-8
CH (COMPARE HAlFWORD) instruction 7-14
example A-12
chain-command (CC) flag in CCW
13-7,13-38
chain-data (CD) flag in cew 13-6,13-38
chaining 13-40 command (See command chaining of
CCWs)
data (See data chaining of CCWs)
flags in CCW for 13-6,13-38
chaining check (channel status) 13-72
change bit in storage key 3-7
change recording 3-10 channel 2-6,13-3
block-multiplexer 13-5
byte-multiplexer 13-4,13-30 control failure (bit in
external-damage code) 11-25
equipment error detected by 13-14
I/O-system reset, as part of subsys­
tem reset 4-34
masks 6-14
difference between EC and BC modes
4-4
in BC-mode PSW 4-8
multiplexer 13-5
not operational (I/O-system state)
13-12
bit in external-damage code 11-25
programming error dptected by 13-14
selector 13-4
timeout used by 13-4
working (I/O-system state) 13-11
channel address 13-8,13-15
channel-address word (See CAW)
channel-available interruption (CAl)
13-29,13-61
channel-command word (See CeW)
channel commands (See commands)
channel-control check (channel status)
13-72
channel-data check (channel status)
13-71
channel end (unit status) 13-67
channel identification (rD) 13-32
assigned storage locations for 3-44
in IOeA (I/O-communication area) 13-80 channel indirect data addressing 13-45
facility D-2
IDA flag used for 13-38
role of in I/O operations 13-6
channel logout (See full channel
logout)
(See also limited channel logout)
channel model 13-32
channel power-on reset 4-35
channel program 13-5
resumption of 13-55
serialization 5-34
suspension of 13-46
channel set 2-6
address 4-43
resetting of connections for 4-34
switching 4-43
switching facility D-2
channel status 13-70 chaining check 13-72
channel-control check 13-72
channel-data check 13-71
incorrect length 13-70 interface-control check 13-72
program check 13-70 program-controlled interruption (PCI) 13-70 protection check 13-71
channel-status word (See CSW)
channel-to-channel adapter 13-2
publication referenced v
channel-type code (specified by STIDC)
13-32
characteristic (of floating-point
number) 9-1
characters, represented by eight-bit
code iv
check bits 3-3,11-2
check stop 4-3,11-10 as signal-processor status 4-42
control bit 11-14,11-28
during manual operation 12-1
Index X-3

effect on CPU timer 4-28
entering of 11-14
indicator 12-2
malfunction alert for 6-12
system 11-11
checking block 11-2
checking-block code (See CaC) checkpoint 11-3
in tracing 4-13
checkpoint synchronization 11-3
action 11-4
operations 11-4 CL (COMPARE LOGICAL) instruction 7-14 CLC (COMPARE LOGICAL) instruction 7-14 example A-13 CLCL (COMPARE LOGICAL LONG) instruction
7-15
example A-14 CLEAR CHANNEL (CLRCH) instruction 13-16
termination of I/O operation by
13-59 CLEAR I/O (CLRIO) instruction 13-17
termination of I/O operation by
13-59 clear-I/O facility D-2
clear reset 4-34
clearing operation
by clear-reset function 4-34
by load-clear key 12-3
by system-reset-clear key 12-5
by TEST BLOCK instruction 10-50 eLI (COMPARE LOGICAL) instruction 7-14 example A-13 CLM (COMPARE LOGICAL CHARACTERS UNDER
MASK) instruction 7-15
example A-14
clock (See TOD clock)
clock comparator 4-27
as part of facility 0-2 external interruption 6-11
save areas for 3-44
validity bit for 11-23
clock unit 4-26 CLR (COMPARE LOGICAL) instruction 7-14
example A-14 CLRCH (CLEAR CHANNEL) instruction 13-16 CLRIO (CLEAR I/O) instruction 13-17
code ASCII, handled by architecture iv
channel-type 13-32
checking-block (See CBC) command (See commands)
condition (See condition code)
decimal digit and sign 8-2 EBCDIC chart for G-l
handled by architecture iv
eight-bit, handled by architecture
i v
exception-extension 6-15
external-damage 11-24
validity bit for instruction-length (See ILC) interruption (See interruption code)
monitor (See monitor code)
operation 5-2 PER (See PER code)
region 11-26
validity bit for 11-22
sequence (in limited channel logout)
13-82
version 10-48 command chaining of CCWs 13-43
X-4 System/370 Principles of Operation chain-command (CC) flag for in CCW 13-7,13-38
during IPL 4-36
command code in CCW (See commands)
command-retry facility D-2,13-53
commands (I/O) 13-48
basic sense 13-51
chaining of 13-43
code in CCW for 13-39
control 13-50 no-operation 13-50 read 13-49
read backward 13-50 rejection of 13-51,13-55
retry of 13-53
sense 13-51
sense ID 13-52
transfer in channel 13-53
write 13-49
commercial instruction set D-l
common-segment bit 3-25
communication area, I/O (See IOCA) COMPARE (C,CR) binary instructions 7-12 COMPARE (CD,CDR,CE,CER) floating-point
instructions 9-8 examples A-37 COMPARE AND SWAP (CS) instruction 7-12
examples A-40 COMPARE DECIMAL (CP) instruction 8-5 example A-31 COMPARE DOUBLE AND SWAP (CDS) instruc­
t;on 7-12
examples A-40 COMPARE HALFWORD (CH) instruction 7-14
example A-12 COMPARE LOGICAL (CL,CLC,CLI,CLR) instructions 7-14
examples A-13 COMPARE LOGICAL CHARACTERS UNDER MASK (CLM) instruction 7-15
example A-14 COMPARE LOGICAL LONG (CLCL) instruction
7-15
example A-14
comparison
address (See address comparison)
decimal 8-5
example A-31
floating-point 9-8
examples A-37
logical 7-4
examples A-13
signed-binary 7-4 TOO-clock 4-27
compatibility 1-3
among systems in the same architec­
tural mode 1-3
of BC-mode PSW with System/360 4-5
of I/O operations 13-7
compatibility differences
between System/360 and System/370 in channel prefetching H-2
in command retry H-2
in I/O operation codes H-l
in logout H-2
in USASCII-8 mode H-1
in validity of data H-2
within System/370 in change bit 1-2 in fetch accesses I-I in operand-access consistency 1-2
in REAL DIRECT and WRITE DIRECT I-I