An MSCH record represents a modify subchannel operation.
MSCH.... shhhh ASCB.... hhhhhhhh CPUID... hhhh JOBN.... cccccccc
SID..... hhhhhhhh CC...... hh OPT..... hh
OPT2.... hh IOSLVL.. hh SCHIB1.. hhhhhhhh
hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh
hhhhhhhh UCBLVL.. hh SCHIB2.. hhhhhhhh
hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh hhhhhhhh
hhhhhhhh
hhhhhhhh UCBWGT.. hh BASE.... shhhh
- MSCH 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 modify
subchannel operation.
- CPU hhhh
- Address of the processor on which the modify subchannel started.
- JOBN cccccccc
- One of the following:
- cccccccc
- Name of the job associated with the task that requested the modify
subchannel operation
- N/A
- Not applicable
- SID hhhhhhhh
- Subchannel ID from the UCBSID field of the UCB.
- CC hh
- MSCH condition code in bits 2 and 3.
- OPT hh
- IOSB option bytes from the IOSOPT field of the IOSB.
- OPT2 hh
- IOSB option bytes from the IOSOPT 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.
- SCHIB1 hhhhhhhh ... hhhhhhhh
- First 7 words of the subchannel information block. Input from
the caller of modify subchannel instruction. SCHIB address from the
IOSSCHIB field of the IOSB.
- UCBLVL hh
- UCB level value from the UCBLEVEL field of the UCB.
- SCHIB2 hhhhhhhh ... hhhhhhhh
- First 7 words of the subchannel information block resulting from
the modify subchannel instruction.
- 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.