SSCH trace records

An SSCH record represents a start subchannel operation.

SSCH.... shhhh ASCB.... hhhhhhhh CPUID... hhhh     JOBN.... cccccccc
               RST..... hhhhhhhh VST..... hhhhhhhh DSID.... hhhhhhhh
               CC...... hh       SEEKA... hhhhhhhh hhhhhhhh
               GPMSK... hh       OPT..... hh       FMSK.... hh
               DVRID... hh       IOSLVL.. hh       UCBLVL.. hh
               UCBWGT.. hh       BASE.... shhhh
               ORB..... hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh
                        hhhhhhhh hhhhhhhh hhhhhhhh

SSCH shhhh

Device number from the UCBCHAN field of the UCB with subchannel set identifier when appropriate.

ASCB hhhhhhhh

Address of the ASCB for the address space that started the I/O operation.

CPU hhhh

Address of the processor on which the I/O operation started.

JOBN cccccccc

One of the following:

cccccccc: Name of the job associated with I/O operation
N/A: Not applicable

RST hhhhhhhh

Address of the channel program. This value comes from the contents of the IOSRST field of the IOSB.

VST hhhhhhhh

Virtual address of the channel program. This value comes from the contents of the IOSVST field of the IOSB.

DSID hhhhhhhh

Request identifier used by purge. This identifier is in the IOSDID field of the IOSB and is the address of the DEB or another control block used by PURGE.

CC hh

SSCH condition code in bits 2 and 3.

SEEKA hhhhhhhh hhhhhhhh

Dynamic seek address from the IOSEEKA field of the IOSB.

GPMSK hh

Guaranteed device path mask for GDP requests from the IOSGPMSK field of the IOSB.

OPT hh

IOSB options byte from the IOSOPT field of the IOSB.

FMSK hh

Mode Set/File mask from the IOSFMSK field of the IOSB.

DVRID hh

Driver ID from the IOSDVRID field of the IOSB.

IOSLVL hh

Function level to provide serialization of I/O requests. This value comes from the IOSLEVEL field of the IOSB.

UCBLVL hh

UCB level value from the UCBLEVEL field of the UCB.

UCBWGT hh

Flags from the UCBWGT field of the UCB.

BASE shhhh

Device number from the UCBCHAN field of the UCB, which includes the subchannel set identifier when appropriate.

ORB hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh

Contents of the operation request block (ORB).