Type ASSEMBLE
Source Lines : 869
Fixes Applied : 7
Most Recent Version : Thursday, December 7, 1978
Last Fix ID : [HRC040DK]
Module
DMKVCH
Function
TO 'ATTACH' OR 'DETACH' A REAL CHANNEL AND ALL DEVICES
ON IT TO A SPECIFIED USER.
+--------+----------------------------+
| ATTACH | CHANNEL X <TO> USERID |
|--------+----------------------------+
| DETACH | CHANNEL X <FROM> <USERID> |
+--------+----------------------------+
THE ACTUAL COMMAND LINE IS DECODED BY DMKVDC.
Attributes
RE-ENTRANT, PAGEABLE, CALLED VIA SVC
Operation
DMKVCHDC IS CALLED BY DMKVDA (ATTACH) OR DMKVDD (DETACH) A
REAL DEVICE AND ALL DEVICES ON THE CHANNEL TO A SPECIFIED
USERID. THE ATTACH/DETACH COMMAND HAS BEEN PROCESSED BY
DMKVDA/DMKVDD AND FLAGS SET IN GPR1, REPRESENTING THE FUNCTION
REQUESTED. THE FOLLOWING CONDITIONS ARE TESTED BEFORE
A CHANNEL CAN BE DEDICATED.
1. MUST NOT BE CHANNEL 0
2. VIRTUAL CHANNEL CANNOT ALREADY EXIST.
3. REAL CHANNEL MUST BE ON THE SYSTEM
4. CHANNEL MUST NOT BE DEDICATED TO ANOTHER USER
5. THERE MUST BE NO CP-VOLUMES ON THE CHANNEL
6. SPOOLING DEVICES MUST BE IN A DRAINED CONDITION
7. DEVICES ON THE CHANNEL CANNOT BE ALREADY ATTACHED
TO ANY USER'S.
IF ALL OF THE ABOVE CONDITIONS ARE SATISFIED; VIRTUAL
CHANNEL, CONTROL UNITS, AND DEVICE BLOKS ARE BUILT. THEY ARE
MAPPED 1 FOR 1 AGAINST THE REAL CHANNEL, CONTROL UNITS, AND
DEVICES. THE DEDICATE BITS ARE TURNED ON. A RESPONSE IS
ISSUED TO THE USER THAT THE CHANNEL HAS BEEN ATTACHED.
TO DETACH A CHANNEL THE FOLLOWING CONDITIONS MUST BE MET;
1. MUST NOT BE CHANNEL 0
2. THE REAL CHANNEL MUST EXIST
3. THE CHANNEL MUST HAVE ALREADY BEEN DEDICATED TO
THIS USER.
IF THE ABOVE CONDITIONS ARE MET; VIRTUAL CHANNEL, CONTROL
UNITS, AND DEVICE BLOKS ARE MARKED UNAVAILABLE. THE DEDICATE
BITS ARE RESET IN THE REAL CONTROL BLOKS. CONTROL REGISTER 2
IS CHANGED IF NECCESSARY TO ALLOW THE CHANNEL TO
BECOME ACTIVE.
Calls to Other Routines
DMKERMSG- TO WRITE MESSAGES
DMKSCNRA - TO OBTAIN THE HEX REAL DEVICE ADDRESS
DMKSCNVU- TO LOCATE VIRTUAL CONTROL BLOKS
DMKSCNRU- TO LOCATE REAL DEVICE CONTROL BLOKS
DMKSCNRD - TO OBTAIN THE HEX REAL DEVICE ADDRESS
DMKVDSAT - TO BUILD VIRTUAL DEVICE BLOCKS FOR ATTACH
DMKVDREL - TO RELEASE VIRTUAL BLOCKS FOR DETACH
DMKFREE - TO OBTAIN STORAGE
DMKFRET - TO RELEASE STORAGE
DMKQCNWT - SEND MESSAGES TO THE TERMINAL