DMKDSB -- Entry from DMKDAS on pack change interruption. If the device is a 3330V, look for an MSSCOM waiting for this volume serial. If one is
found, stack a CPFIBLOK for entry to DMKSSSEN. Exit to DMKDSP. DMKSSSEN ---PIck-up -the CPEIBLOK for DMKLNKSS and stack it. DMKLNKSS ---complete the LINK processing for the minidisk. LOGON A USER HAVING A 3330V DEDICATED AS A 3330V Determine that a virtual 3330V is needed, save the UDEVBLOK, call DMKSSSL1. Go through device allocation, etc., to schedule a mount. DMKLOG, MSSMOUNT MS5-mount is in process (return code 4 from DMKSSS), proceed to
get the next directory statement. Otherwise, find the RDEVBLOK for
the device that DMKSSS allocated and continue the dedicat process. DMKLOGSS from DMKDSB and DMKSSSEN after .ount. Get the RDEVBLOK DMKVDSAT the virtual device. TST!JJJ! If the virtual device is a 3330V, set flag RDEV333V to indicate that
there is no CP MSS CCW prefix. If there is virtual I/O waiting, as indicated by a CPEXBLOK address
in field MSSTASK3 of the MSSCOM used for the mount, stack the IOBLOK. Return to DMKDSP. PROCESS DIAGNOSE CODE 1'78' Entry from DMKHVC when DIAGNOSE code is 1'78'. The entry subcode was O. Save the communication device address and
the communicator VMBLOK address. Set PSAMSS indicating that the Mse is now available.· The entry subcode was 4. If there is an MsseOM in the queue to be processed, call DMKPTRAN to get the communicator's buffer address.
Put the MsseOM in the virtual machine buffer.
1-424 IBM VM/370 System Logic and Problem Determination--Volume 1

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