File Management - IBM

v A notify, status, diagnostic, or escape message may be sent to the operator
message queue (QSYSOPR) or the history message queue (QHST).
v Information regarding the error may be saved in the system error log for use by
the problem analysis and resolution programs.
v An alert message may be sent to an operator at another system in the network.
v The normal program flow may be interrupted and control may be transferred to
an error-handling subroutine, or other language operations may occur. For
additional information about how to handle run-time errors, see the appropriate
book for the high-level language.
Only some of these are significant to a program that is attempting error recovery.
Actions to take when you receive an error:
See “Recovering from file system errors” on page 28 for information on the actions
you should take when you receive an error.
Nonrecoverable errors:
Not all file errors allow programmed error recovery. Some errors are permanent;
that is, the file, device, or program cannot work until you take some corrective
action. This might involve resetting the device by varying it off and on again, or
correcting an error in the device configuration or the application program. Some
messages and return codes inform the user or the application program of
conditions that are information rather than errors, such as change in the status of a
communications line, or system action taken for an unexpected condition. In many
cases, it is possible for the application program to test for an error condition and
take some preplanned recovery action which allows the program to continue
without intervention from the operator.
For more information:
The CL Programming, SC41-5721-03 book discusses how to use the debug functions
to resolve unexpected errors that you encounter in the application programs.
The chapter on handling problems in the Basic System Operation, Administration, and
Problem Handling, SC41-5206-04 book describes the programs that are available for
analyzing and reporting system errors and hardware failures.
Messages and message monitors in files by the system
Displayed messages are the primary source of information for an operator or a
programmer who is testing a new application. A message usually contains more
specific information than the file status code, the indicators, and the major and
minor return code. The control language lets you monitor messages so that the CL
program can intercept a message and take corrective action. See the CL
Programming, SC41-5721-03 book for more information about message types and
message monitors. In most high-level languages, the file status code and return
codes (which are described in the following section) are more convenient sources
of information.
Message numbers are assigned in categories to make it easier for a program to
monitor for a group of related messages. Table 6 on page 26 shows the message
number ranges that are assigned for file error messages.
Chapter 2. File processing 25