031

Explanation
The system did not find a unit control block for
the device containing the system residence (SYSRES) volume, for one
of the following reasons: The system was IPLed using the wrong SYSRES volume
The SYSRES volume was not specified in the I/O configuration definition
The system did not select the desired I/O configuration.

System action
The system enters wait state X'031'.

Operator response
Depending on the reason that this wait state
code was issued, do the following: If the system was IPLed using the wrong SYSRES volume, then mount
the correct SYSRES volume and reIPL the system.
If the SYSRES volume was not specified in the I/O configuration
definition, then notify the system programmer to rebuild the I/O configuration
to include the correct SYSRES volume.
If the system did not select the desired I/O configuration, use
the following steps to determine which I/O configuration was selected;
then notify the system programmer: Using the hardware Alter/Display facility, read the real address
in central storage at X'14', representing the address of
the IPL diagnostic area.
Add X'28' to the address in X'14',
and also read this as a real address in central storage. The result
is a 31-bit virtual address, which is the IPL vector table (IVT).
 Henceforth, all addresses are 31-bit virtual and you must switch
to displaying Primary Virtual Storage to display remaining storage
locations. Note that the following addresses are also 31-bit virtual
addresses.
Add X'E0' to the address of IVT to locate the IVTMQHP
field, which points to the message queue header (MQH).
MQH + X'0' points to the oldest message queue element
(MQE) available.  Message text beings at MQH + X'8'.  This
message should be IEA371I, showing the device number and data set
(SYS1.PARMLIB or SYS1.IPLPARM) used to located the selected LOADxx
member.
MQE + X'0' of the oldest MQE points to the second oldest
MQE. This message should be IEA246I, showing which LOADxx member was
selected.
MQE + X'0' of the oldest MQE points to the third oldest
MQE. This message should be either IEA097I, showing which MVSCP IOCONFIG
was selected, or IEA519I, showing which IODF was selected.

System programmer response
If the SYSRES volume was not specified
in the I/O configuration definition, then rebuild the I/O configuration
to include the correct SYSRES volume.
If the system did not
select the desired I/O configuration, then ensure that the device
number, data set (SYS1.PARMLIB or SYS1.IPLPARM), LOADxx member, and
I/O configuration were specified correctly.  Also, if LOADxx filtering
keywords (HWNAME, LPARNAME and VMUSERID) were being used, ensure that
the keywords were specified correctly.  For more information on the
filtering keywords in LOADxx, see the "Filtering with LOADxx" chapter
in z/OS MVS Initialization and Tuning Reference .

Source
Input/output supervisor (IOS)