Use this command to set the timeout value for the lost interrupt recovery
routine in the DASD missing interrupt handler (DMIH). The DMIH monitors
the DASD I/O to ensure that the DASD devices are responding in a timely
method.
This command does the following:
- Starts the DMIH (if the value specified for this command is not 0).
- The DMIH attempts to stop and restart requests that were active for longer
than a specified period of time and, as a result, issues a CTL-03A
dump.
- If the request does not complete again in the specified time interval, the
DMIH stops the request and takes the module offline.
Requirements and Restrictions
You can enter this command only for the basic subsystem (BSS).
Format
- Time-seconds
- specifies the time interval that the DMIH waits before stopping and
restarting a request after a 5-second timeout interval ends, where
seconds is the number of seconds from 0-999.
Notes:
- If you specify 0, no recovery routines are started.
- The time interval is initially set to 0 by the TPF system.
Additional Information
- When running on a VM system, the 5-second timeout interval and the value
specified for this command are doubled.
- The CYED program also uses the value specified for this command to recover
from stalled module queues as follows:
- Determines that the module queue is stalled and the normal DMIH recovery
is not going to recover from it.
- Starts a recovery routine, which issues a CTL-003A dump.
- Resets the device and restarts the first request on the module
queue.
- Note:
- The CYED program determines when to start the recovery routine by taking the
normal DMIH timeout value (5 seconds), doubling this value, and adding the
value specified for this command to it.
- If you specify a value greater than 0 for TPF systems that use nonbuffered
or noncache DASD control units, damaged records on the DASD surface can
result.
- Enter the ZSONS DISPLAY HALT command to display the current timeout value
for the DMIH.
Examples
In the following example, the lost interrupt timeout value for the DMIH
recovery routine is set to 15 seconds.
+--------------------------------------------------------------------------------+
|User: ZSONS A H T-15 |
| |
|System: SONS0001I 09.40.59 HALT TIMEOUT VALUE IS 15 |
+--------------------------------------------------------------------------------+
Related Information
See TPF Database Reference for more information
about DASD support.