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Hex Dec Type/Val Lng Label (dup) Comments
---- ---- --------- ---- -------------- --------
0000 0 Structure CHPBK SPXTAPE Channel Program Block
Reserve space for the base IORBK
0000 0 Dbl-Word 8 CHPIORBK (73) Base IORBK region
Lock for this IORBK and CHPBK work area
0248 584 Dbl-Word 8 CHPLOCK (3) Lock to serialize this block
Commit and recovery control data.
Last items in the current block
used to update commit cursors when
successfully sent to tape.
0260 608 Signed 2 CHPCMCLR (0) Beginning of area to be cleared
before reuse for trailer
0260 608 Address 4 CHPCURTK Last ticket contained in current
block
0264 612 Address 4 CHPCMSSQ Last SSQBK
0268 616 Address 4 CHPCMCUR Address of next Vpage slot in
last SSQBK
026C 620 Signed 4 CHPCURHD Displacement in header of cur hdr
0270 624 Signed 4 CHPCMXAB Amt of XAB data associated with
last tkt remaining to be written
0274 628 Address 4 CHPLSTCW CCW address of the last piece of
data for files that completed in
the current block. If = 0 then
block contains no complete files
0278 632 Signed 4 CHPLLPTR Last offset in page list +1 used
027C 636 Address 4 CHPLSTHD Hdr addr for last completed file
0280 640 Signed 4 CHPLBLKZ Save last block size at last
complete file/tkt in this block.
Counters, etc.
0284 644 Character 16 CHPTKTS Queue of files completed in this
channel program. Moved to TAPTKTQ
when I/O completes OK.
Single-threaded double-headed
FIFO queue terminated by zero
0284 644 Address 4 CHPTKTSH Head of CHPTKTS
0288 648 Address 4 CHPTKTST Tail of CHPTKTS
028C 652 Signed 4 CHPTKTCT Corresponding count of files on
CHPTKTS
0290 656 Signed 4 * Reserved
0294 660 Signed 4 CHPENTRY Current entry in the header
0298 664 Signed 4 CHPLIMIT After the last entry in the hdr
029C 668 Signed 4 CHPLINDX Index into CCW list of buffers
02A0 672 Signed 4 CHPOFFST Offset into block where data
should be added
02A4 676 Signed 4 *
02A8 680 Signed 4 CHPPOOLC Count of pool pages (data pages)
02AC 684 Address 4 CHPPLIST (14) List of pages locked for this blk
00000038 CHPPLLEN *-CHPPLIST Length to clear
0000000E CHPPLMAX 14 Maximum number of entries
02E4 740 Signed 4 * End flag for PLIST - zero = end
00000088 CHPCMCRL *-CHPCMCLR Length of area to be
cleared before reuse for trailer
Queue of CHPbks link field
02E8 744 Address 4 CHPNEXT Next work area in circular queue
Save area across GOTO I/O request
02EC 748 Signed 4 CHPSAVE (7) Save R3-R9 across call to IOS.QS
Channel Program and Header Block copied from TAPBK
0308 776 Dbl-Word 8 CHPPGM (26) Modeset + hdr + 3*8 (desc + xab +
data)
03D8 984 Dbl-Word 8 CHPHEADR (37) Block header
Pointers
0500 1280 Signed 4 CHPIDAWA IDAW list anchor
0504 1284 Signed 4 CHPIDWNX Next available IDAW slot
0508 1288 Signed 4 CHPBUFHL Host logical buffer addr anchor
050C 1292 Signed 4 * Reserved
00000004 CHPHLLEN 4 Length of CHPBUFHL entries
End of CHPBK definition
0510 1296 Dbl-Word 8 CHPRESVD (10) Round it off
00000318 CHPLENBY *-CHPLOCK Extra space (after
IORBK)
00000560 CHPIOBY *-CHPBK Whole work area size in
bytes
000000AC CHPIODW CHPIOBY/8 Same in double words
00000002 CHPBKCNT 2 Number of work areas per drive
Redefinition for the channel program build area
0308 776 Dbl-Word 8 CHPMSCCW Modeset, if applicable
0310 784 Address 4 CHPHDCCW Read/write header CCW
0314 788 Address 4 CHPHCCWA Address of the CHPHEADR
0318 792 Address 4 CHPCCW1 First general CCW
031C 796 Address 4 CHPCCW1A Address section for deblocking
0320 800 Dbl-Word 8 CHPCCWS (20) File write CCWs - desc, XAB, data
Or read CCW's - up to 8 pages
00000015 CHPCCWCT (*-CHPCCW1)/8 Number of CCWs
(doublewords)
000000B8 CHPPGMLN *-CHPPGM Must match size defined
above
Redefinition for the tape block header section
03D8 984 Character 4 CHPBLKID Generally 'XHDR', could be 'TRLR'
03DC 988 Signed 4 CHPBLKSZ Size of this block in bytes
03E0 992 Dbl-Word 8 CHPTIME Time stamp
Definition of an individual entry
03E8 1000 Dbl-Word 8 CHPHDENT (0) Start of the first entry
03E8 1000 Character 8 CHPOWNER File owner
03F0 1008 Signed 4 CHPFSEQ File sequence number for drive
03F4 1012 Signed 4 CHPSYSID System spool file ID when dumped
03F8 1016 Signed 2 CHPSPID User spool file ID when dumped
03FA 1018 Bitstring 1 CHPHDFLG Flags describing file section
03FB 1019 Bitstring 1 *
03FC 1020 Signed 4 CHPMAPCT Count of map pages needed for
file
0400 1024 Signed 4 CHPPAGNO Starting relative page number
0404 1028 Signed 2 CHPPAGCT Count of data pages in block
0406 1030 Signed 2 CHPXABSZ Size of XAB section in block
0408 1032 Signed 2 CHPTKOFF Offset to ticket - file
descriptor
040A 1034 Signed 2 CHPXAOFF Offset to extended attributes buf
040C 1036 Signed 2 CHPDPOFF Offset to data pages
040E 1038 Signed 2 *
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