Hexadecimal
Displacement
------------
B C 10 18 20 22
24
28 30 38
o
8
9
A
B C 10 18 20 22
24
28 30 38
Field
Name CHXPKEY DS DS CHXNCCW DS CHIRCNT DS CBXSTAT DS CHXYADD DS DS CBXIDAW DS CBXCNCT DS CBXDATN DS CBBSIZE EQU 1X 4X 2F
2F
1B
1B
2B
2F
2F
2F CBXBLOK,CBYELCK . Field Description, Contents, eeaning X*4 Virtual CAW protection key
"Other" adapter control flags
Next CCW fetch address (real)
Remaining CCW data count tevice status accumulation field Virtual address of Y-side adaFter
"Other" adaFter control flags
Active indirect data list word CPEXELOK for channel reconnect IOELCK address for deferred I/O interruFt (*-CBXBLOK)/8 Total block size in doublewords (X'08') CBYBLOK Y-side channel adapter block CBYOTBR DS CBYFLAG DS CBBMNOP EQU CBBM370 EQU CBBATTN EQU CBBREST EQU CBBEOFL EQU CBBBIO EQU CBBWAIT EQU CBBEENT EQU CHYCMDB DS CBYCMDT DS Bit§ CBBCNTL EQU CBBRDBK EQU CBBWEOF EQU CBBSCMD EQU CHBS!DS EQU CBBREAD EQU CBBWRIT EQU CHYPKEY DS DS CHYNCCW DS CBYRCNT DS CBYSTAT DS CHYXADD DS DS CBYIDAW DS CBYCNCT DS CBYDATN DS 2F 1X in CBYFLAG --X'SO'- X'40' X'20' X'10' X'08' X'04' X'02' X'01' 1X 1X in CBYCMDT -x''4o'­ X'20' X'10' X'08' X'04' X'02' X'01' 1X 4X 2F
2F
1B
1B
2B
2F
2F
2F VMELCK address of X-side adaFter user Y*1 Internal processing flags Modified NOF command issued (also in CMDT) CTCA operating in System/370 mode
Attention pending from X-side CTCA has been reset X-side and Y-side Force EOF to next READ instruction
Halt 1/0 or halt device issued CPEXELOK availatle for channel reconnect Channel end has been preserved cn SIO Y*2 Active CCW command tyte buffer Y*3 Active CCW command type (Rt, WB, etc.) Control, other than NOP Read tackward Write EOF Sense command byte
Sense adapter status
Bead
write Y*4 Virtual CAW protection key
"Other" adapter control flags
Next CCW fetch address (real)
Bemaining CCW data count
Device status accumulation field Virtual address of X-side adaFter
"Other" adaFter control flags
Active indirect data list word CPEXELOK for channel reconnect IOELCK address for deferred I/O interruFt
Section 1. CP Data Areas and Centrol Blocks 13

CKPBLOK CKPBLOK provides checkpoint information needed for VM/370 warm start recovery for 3704/3705 Communication Controllers and enabled lines and resources. Tbe RDEVCKPT field
of the RDEVBLOK points to CKPBLOK. Hexadecimal
o
a 10 Displacellent
------------ 0 2
4
8 10 I CKPSIZE CKPRMAX 1//////////CKPRSV1//////////1 --------------------------------------------------------1 CKPNAME 1 ------------------------------------------------------1
Field
Nalle CKPSIZE DS CKPRMAX DS CKPRSV1 DS CKPNAME DS CKPBITS DS CKPBKSZ EQU 1H 18 1F
CLa OD CKPBITS I Field Description, Contents, Meaning Size of checkpoint block in dcublewords
Number of resources checkpcinted
Reserved for IBM use 370x control program reference nalle Bit map of enabled lines or rescurces (CKPBITS-CKPBLOK)/a Header size in doublewcrds
14 IBM VM/370 Data Areas and Control Block Logic