DMKSSS, HVC08ENT entry-subcode was 8. The MSC has processed a request. If there
was an error, write message DMKSSS088E, dequeue the MSSCOM, stack the
return to the DMKSSS caller from MSSTASK2 with a return code 8, and
return to DMKHVC. If there was no MSC error, stack the MSSTASK2 CPEXBLOK with a return code of 4, and return to DMKHVC. GENERATE THE CHANNEL PROGRAM PREFIX FOR A 3330V Entry to generate a real channel program from a virtual machine
channel prograii. CCiIN!!2!! If the real device is a 3330V, set a flag indicating that the MSS channel program prefix is needed. If the prefix-needed flag is on and the virtual device is not a
virtual 3330V, put the prefix in the RCWTASK. DMKCCW, DASDTBL AND DEDDTBL of-addresses of routines that are to get control to
process specific CCW operation codes for DASD and dedicated devices.
In each subroutine, a check is made to see if there is an unresolved MSS prefix. If so, it checks to see if the virtual channel program contains a SEEK. If so, it checks to see if the argument is used to
generate the SEEK argument for the prefix. If not, the prefix CCW is
set to SEEK to cylinder O. GENERATE THE CHANNEL PROGRAM PREFIX FOR CMS I/O TO A 3330V Entry to process I/O requests to DASD as initiated by the special DIAGNOSE code '78' interface from CMS. NOPRE If the real device is a 3330V, set up the prefix in the RCWTISK. The VDEVBLOK for the virtual device could not be found. Check to see
if there is an MSS mount in process for the required system volume.
If so, build a CPEVBLOK for this request, Fut the address in the MSSTASK3 field of the MSSCOM, and exit to DMKDSP. PROCESS A STAGING ADAPTER CYLINDER FAULT DMKIOSIN when ending status is received from a device. Check to see if
the CSW contains CE-DE with no error status. TES!£!b If the device type is a 3330V, see if the CE-DE is in the MSS prefix NOP CCW. If not, or if the device is dedicated as a virtual 3330V, stack the IOBLOK. Appendix B: VM/370 MSS Support 1-425

DMKSSS12 ---Set--the IOBFLT flag, indicating that a cylinder fault is being
resolved. Chain the IOBLOK from the REDEVFIOE field in the RDEVBLOK. Build a TRQBLOK to recognize missing attenticn interruptions and put
it on the timer queue. Exit to the dispatcher. PROCESS AN ATTENTION INTERRUPT FRO! A 3330V Entry to process unsolicited I/O interrupts. If the interrupt is an attention, the device is a 3330V, and it is
not dedicated as a 3330V. Call DMKSSSl1 to restart I/O. DMKSSSl1 ---Pind-each IOBLOK for this device that
the associated timer queue element
queue. Turn off IOBFLT so that the
device is available.
has the IOBFLT flag set. Find
and remove it fro. the timer IOBLOK can be restarted when the
1-426 IBM VM/370 System Logic and Problem Determination--Volume 1