The address of the VCUBLOK table is found in the VCUSTRT field
(displacement X'1C') of the VMBLOK. General register 7 contains the
address of the active VCUBLOK. Useful information is contained in the
following fields:
1. The virtual control unit address is found in the VCUADD field
(displacement X' 00') 2. The value of the VCUSTAT field (displacement X'06') indicates the
status of the virtual control unit: Value of VCUSTAT Feo'-- X'40' X'20' X'10' X'OS' X'04' comments iIrtuaI-subchannel busy
Interrupt- pending in subchannel Virtual control unit busy Virtual control unit interrupt pending Virtual control unit end pending Virtual control unit active
3. The value of the VCUTYPE field (displacement X'07') indicates the
type of the virtual control unit: Value of VCUTYPE X'SO,-- X'40' Comments iIrtual-control unit on shared subchannel Virtual control unit is a channel-to-channel
adapter
The address of the VDEVBLOK table is found in the VMDVSTRT field
(displacement X'20') of the VMBLOK. General register S contains the
address of the active VDEVBLOK. Useful information is contained in the
following fields:
1. The virtual device address is found in
(displacement X'OO'). the VDEVADD field
2. The value of the VDEVSTAT field (displacement X'06') describes the
status of the virtual device: Value of X'SO' X'40' X'20' X'10' X'OS' X'04' X'02' X'01' Comments iIrtuaI-subchannel busy Virtual channel interrupt pending Virtual device busy Virtual device interrupt pending Virtual control unit end Virtual device not ready Virtual device attached by console function VDEVREAL is dedicated to device RDEVBLOK
3. The value of the VDEVPLAG field (displacement X'01') indicates the
device-dependent information:
value of X'SO' X'SO' X'40' X'40' X'40' X'20' X'10' X'10' X'OS' X'OS' X'04' X'02' X'02' X'01' £2!!m!!§-- DASD -- read-only device Virtual 2701/2702/2703 device line enabled D1SD -- TDISK space allocated by CP Virtual 2701/2702/2703 device line connected
Console --activity spooled DASD -- 2311 device simulated on top half of 2314 DASD -- 2311 device simulated on bottom half of 2314
Console and spooling device --processing first ccw DASD -- executing standalone seek
Console --delay spooling Virtual device is being attached RESERVE/RELEASE are valid CCi operation codes
present attention with a single interrupt Virtual device sense bytes present
4. The VDEVCSW field (displacement X'08') contains the virtual channel
status word for the last interrupt.
5. The VDEVREAL field (displacement X'24') contains the pointer to the
real device block, 6. The VDEVIOB field (displacement X'34') contains the pointer to the
active IOBLOK. 7. For console devices, the value of the VDEVCFLG field (displacement X'26') describes the virtual console flags: Value of X'SO' X'40' X'20' X'10' X'OS' COllments user-SIgnalled attention tee many times
Last CCi processed was a TIC Data transfer occurred during this channel program Virtual console function in progress
Automatic carriage return on first read
8. For spooling devices, the value of the VDEVSFLG field (displacement X'21') describes the virtual spooling flags: Value of X'SO' X'40' X'20' X'10' X'OS' X'OS' X'04' X'02' X'02' X'01' comments spcor-output -- transferred to VSPXXUSR Spool device --continuous operation
Hold output --save input
spool output --for user and distribution
spool input --set unit exception at EOP Terminal output required for spooled console
Device closed by console function Spool output --purge file at close
spool input --device opened by DIAGNOSE Spool output -- DMKVSP entered via SVC Part 1. Debugging with VM/370 55
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