CCW trace records

A CCW record represents the processing of a non-zHPF channel program. CCW trace records appear following EOS, IO, IOCS PCI, RSCH, or SSCH trace records; they do not appear alone. Any of the formats can appear in any combination in one CCW trace record.

  CCW CHAIN   FORMAT d          ccc               DEV..... hhhh
  ASCB.... hhhhhhhh CPU..... hhhh     JOBN.... cccccccc
  Fhhhhhhh ---CCW-- ---CCW-- dddddddd dddddddd | cccccccc |
  Fhhhhhhh ---CCW-- ---CCW-- dddddddd dddddddd | cccccccc |
  Fhhhhhhh ---CCW-- ---CCW-- dddddddd dddddddd | cccccccc |
                             dddddddd dddddddd | cccccccc |
                             dddddddd dddddddd | cccccccc |
                             dddddddd dddddddd | cccccccc |
                             dddddddd dddddddd | cccccccc |
                             dddddddd dddddddd | cccccccc |
                              .
                              --Back half of split data--
                              .
                             dddddddd dddddddd | cccccccc |
                             dddddddd dddddddd | cccccccc |
  Fhhhhhhh ---CCW-- ---CCW-- dddddddd dddddddd | cccccccc |
 IDAW hhhhhhhh_hhhhhhhh hhhh hhhhhhhh hhhhhhhh | cccccccc |
                             hhhhhhhh hhhhhhhh | cccccccc |
MIDAW hhhhhhhh hhhhhhhh hhhh hhhhhhhh hhhhhhhh | cccccccc |
      hhhhhhhh_hhhhhhhh      hhhhhhhh hhhhhhhh | cccccccc |
 IOSB hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh
               hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh
 EWAx hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh
               hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh

FORMAT d ccc

Format (d) and type of trace event (ccc): EOS, IO, IOCS, PCI, RSCH, or SSCH. Format is either zero or 1.

DEV shhhh

DEV snnnn

Device number from the UCBCHAN field of the UCB. This number is qualified with the subchannel identifier (UCBSID).

ASCB hhhhhhhh

Same as the ASCB field in the IO, IOCS, SSCH, RSCH, PCI, or EOS base record.

CPU hhhh

Same as the CPU ID field in the IO, IOCS, SSCH, RSCH, PCI, or EOS base record.

JOBN cccccccc

Same as the job named (JOBN) field in the IO, IOCS, SSCH, RSCH, PCI, or EOS base record.

Fhhhhhhh

Fullword address of the CCW. If the high order bit of the address is on, this is the real address of the CCW, otherwise this is the virtual address of the address of the CCW.

---CCW--

Is the CCW command. The command is either a format 0 or format 1 CCW.

Format 0 CCW is in the format ooaaaaaa ffuubbbb
Format 1 CCW is in the format ooffbbbb aaaaaaaa
oo

op code.

aaaaaa

Real address of data associated with the CCW. If indirect address words (IDAWs) are present, this is the address of the IDAW list.

aaaaaaaa

Fullword real address of data associated with the CCW. If IDAWs are present, this is the address of the IDAW list.

ff

CCW flags; if this flag is .... .1.. , then this indicates that an IDAW list is present. If this flag is .... ..1., then a suspend of the channel program was requested. If this flag is .... ...1 , then a modified indirect addressing word list is present.

uu

Not used by hardware; could contain a nonzero character.

bbbb

Byte count.

dddddddd dddddddd | cccccccc |

Information transferred by the CCW. If there is not a series of dashes in this field, then all transferred data is displayed in four byte sections.

--Back half of split data--

Indicates there were more bytes of information transferred than were specified on the START command. The default value is 20 bytes, but you can specify the number of bytes to be shown. The specified value is halved; for an odd number, the larger section is shown first. The first section of data displayed comes from the beginning of the buffer from which the data was transferred. The last section comes from the end of the buffer.

IDAW hhhhhhhh or hhhhhhhh_hhhhhhhh hhhh

Contents of the IDAW, a fullword real address for 31–bit IDAWs or a doubleword real address for 64–bit IDAWs, followed by a halfword specifying the length of the data at that address. The data at the address follows the halfword length. The hhhhhhhh_hhhhhhhh version of this parameter specifies 64–bit.

MIDAW hhhhhhhh hhhhhhhh hhhh hhhhhhhh_hhhhhhhh

The modified indirect addressing word (MIDAW), which is 16 bytes, formatted in the GTF trace with the first 8 bytes on the first line containing the flags and data length and the second line containing the 64 bit data address. The length of the data is replicated after the first 8 bytes of MIDAW data to make it easier to read and maintain consistency with the IDAW format. The data at the address follows the halfword length. The data for a MIDAW is not formatted if the skip indicator is on.

IOSB hhhhhhhh

Fullword virtual address of the IOSB followed by the contents of the IOSB. The fullword at offset X'34' of the IOSB points to an error recover procedure work area (EWA), or is zero. The EWA is traced and documented directly below the IOSB and is formatted in the same manner as the IOSB.

EWAx hhhhhhhh

Fullword virtual address of the error recovery procedure work area, followed by the contents of EWA.