Explanation
The system found one of the following along a path
to a device:
- An inoperative control unit
- A channel error
- An undetermined error
There is no device reservation or active I/O operation
on the path to indicate which system owns the device.
If the
system could not determine the channel path identifier and/or device
number, the system substitutes X'FFFF' for the channel path
identifier and/or device number.
System action
The system:
- Disables the device.
- Enters wait state X'06F' because it cannot issue message
IOS427A.
- Expects an operator action, but does not prompt the operator for
a reply.
Operator response
Do the following:
- Find the address of the error information by using the hardware
Alter/Display facility to display the contents of location X'40C'.
Record the first 4 bytes of data at this location.
- Use the hardware Alter/Display facility to display the storage
pointed to by location X'40C'.
Note: This is indirect addressing.
The
system displays the contents of the error information area:
- Offset 0
- The channel path identifier (or X'FFFF', if the CHPID
could not be determined).
- Offset 2
- The device number (or X'FFFF', if the device number could
not be determined).
- Use the hardware Alter/Display facility to change location X'30E' to
one of the following recovery codes:
- Code
- Explanation
- 00
- Try to restart the device without attempting recovery. (Entering
this code is the same as replying 'NOOP' to message IOS427A). If the
problem persists, the system issues message IOS427A again (or wait
state code X'06F' if the system cannot issue IOS427A); consider
entering one of the other recovery codes.
Use the Restart facility
to restart the waiting processor.
- 01
- Attempt to recovery access to the device through an alternate
channel path. (Entering this code is the same as replying X'UR' to
message IOS427A). Before entering this recovery code and restarting
the processor, all other processors that share the device you must
prevent from initiating I/O to this device by issuing the IOACTION
STOP command. If this command fails, you must stop all sharing processors
to prevent I/O activity to the shared device.
Use the Restart facility
to restart the waiting processor. The system might issue one of the
following messages:
- IOS428I - the attempt to access the device through an alternate
channel path was successful.
- IOS104I - the attempt to access the device through an alternate
channel path was not successful.
After the system issues either message, start I/O to
the shared device either by issuing the IOACTION RESUME command or
by restarting the sharing processors if they were stopped in step
11.
- 02
- Force the device offline. (Entering this code is the same as replying X'BOX' to
message IOS427A). The system issues message IOS501I. Use the Restart
facility to restart the waiting processor.
See message IOS427A in z/OS MVS System Messages, Vol 10 (IXC-IZP)
for additional information.
Source
Input/output supervisor (IOS)