Type ASSEMBLE
Source Lines : 1,474
Fixes Applied : 13
Most Recent Version : Thursday, December 7, 1978
Last Fix ID : [HRC202DK]
Function
WHILE EXECUTING A CP GENERATED DASD CHANNEL PROGRAM.
THE ORIGINAL CHANNEL PROGRAM WILL BE RETRIED WHEN POSSIBLE
TO CORRECT THE FAILING CONDITION. IF THE ERROR CONDITION
IS UNCORRECTABLE CONTROL WILL BE PASSED TO THE MESSAGE
WRITER (DMKMSW) FOR OPERATOR AWARENESS. UPON RETURNING
FROM MESSAGE WRITER THE ORIGINAL CHANNEL PROGRAM MAY BE
RE-EXECUTED OR TERMINATED. ALSO STATISTICAL COUNTERS
FOR 2314 TYPE DEVICE WILL BE UPDATED.
Operation
THE ADDRESS OF THE IOERBLOK IN THE RDEVBLOK.
B. TEST FOR CHANNEL ERRORS.
1. CHANNEL DATA CHECKS ARE RETRIED 10 TIMES.
2. INTERFACE AND CHANNEL CONTROL CHECKS ARE
RETRIED 10 TIMES.
C. TEST FOR THE SPECIFIC TYPE OF ERROR.
1. EQUIPMENT CHECK - THE OPERATION IS RETRIED 10 TIMES
2. NO RECORD FOUND (NRF) CONDITION (2314/2319) A READ
HOME ADDRESS IS EXECUTED AND THE DATA IS COMPARED
TO THE SEEK ADDRESS. IF THE COMPARISON IS UNEQUAL
A RECALIBRATE IS EXECUTED AND THE ORIGINAL CHANNEL
PROGRAM IS RETRIED FOR A MAXIMUM OF 10 TIMES. IF
THE COMPARISON IS EQUAL RETURN TO THE CALLER.
NO RECORD FOUND CONDITION (2305/3330/3340) RETURN
TO CALLER
3. SEEK CHECKS ARE RETRIED 10 TIMES, EXCEPT THE
3330/50/80 HAVE BEEN RETRIED ALREADY. HRC011DK
4. INTERVENTION REQUIRED - READ THE VOLID; IF PACK
WAS CHANGED UNLOAD THE ENVIRONMENTAL BUFFER
(3330/40/50/80) AND IF THE VOLUME WAS USED HRC011DK
SYSTEM MARK DEVICE OFFLINE (MSG DMKDAS956).
IN ANY CASE RESTART THE OPERATION.
5. BUS-OUT CHECK - RETRY THE OPERATION ONCE.
6. DATA CHECKS (2314/2319) ARE RETRIED 256 TIMES WITH
RECALIBRATIONS BEING EXECUTED EVERY 16 TIMES.
EXCEPTIONS ARE : (A) THE 3330/50/80 HAVE HRC011DK
BEEN RETRIED BY THE HARDWARE. (B). 3340 AND 2305
WILL BE RETRIED 10 TIMES.
7. OVERRUN - THE OPERATION IS RETRIED 10 TIMES.
8. MISSING ADDRESS MARKER-THE OPERATION IS RETRIED
10 TIMES.
9. COMMAND REJECT - RETURN TO THE CALLER
10. TRACK CONDITION CHECK - IF THIS IS A DEFECTIVE
TRACK CALL DMKTRKIN FOR 3340/3344 DISKS. FOR OTHER
TYPES, AN OPERATOR MESSAGE IS ISSUED.
11. END-OF CYL,TRACK OVERFLOW,AND FILE PROTECT
CONDITIONS- RETURN TO CALLER.
12. CHAINING CHECK- TEST FOR COMMAND REJECT.
IF NOT PRESENT RETRY THE OPERATION 10 TIMES.
13. ENVIRONMENTAL DATA PRESENT HRC011DK
(3330/3340/3350/3380/2305) HRC011DK
RE-EXECUTE THE ORIGINAL CHANNEL PROGRAM.
D. IF THE RETRY PROCEDURE HAS BEEN EXHAUSTED AND
UNSUCCESSFUL CALL DMKMSW FOR OPERATION OPTIONS.
(I.E. CANCEL,RETRY,IGNORE) THE RESPONSES ALLOWED
WILL BE BASED ON THE CONDITION CAUSING THIS ERROR.
E. WHEN THE RETRY PROCEDURE IS FINISHED (EITHER CORRECTED
OR UNCORRECTABLE), CALL DMKIOEST TO CAUSE STATISTICAL
COUNTERS FOR 2314 TYPE DEVICES TO BE UPDATED.
F. CYL POSITION VERIFICATION WILL ONLY BE
PERFORMED IF THE FIRST CCW IN THE CHANNEL PROGRAM
IS A SEEK AND THE SEEK COMMAND IS VALID.
Calls to Other Routines
1. DMKMSW - TO PROVIDE OPERATOR COMMUNICATION
IN ATTEMPTING TO CORRECT THE
ERROR CONDITION.
2. DMKFREE - TO OBTAIN STORAGE FOR DASD
ENVIRONMENTAL SENSE DATA. THIS
CONDITION OCCURS WHEN THE CONTROL
UNIT INDICATES AN OVERFLOW OF THE
USAGE COUNTER.
3. DMKFRET - TO RETURN STORAGE OBTAINED BY DMKFRE
4. DMKQCNWT - TO WRITE MSG DAS956A TO OPERATOR
5. DMKCVTBH - TO CONVERT REAL DEVICE ADDRESS
6. DMKIOEST - TO UPDATE STATISTICAL DATA COUNTERS
7. DMKTRKIN - TO HANDLE TRACK CONDITION CHECKS