Load Map
The load map of a disk-resident command module contains the location of
control sections and entry points loaded into storage. It may also
contain certain messages and card images of any invalid cards or replace
cards that exist in the loaded files. The loadmap is contained in the
third record of the MODULE file.
This load map is useful in debugging. When using the Debug
environment to analyze a program, use the program's load map to help in
displaying information.
There are two ways to get a load map.
1. When loading relocatable object code into storage, make sure that
the MAP option is in effect when the LOAD command is issued. Since MAP is the default option, just be sure that NOMAP is not
specified. A load map is then created on the primary disk each
time a LOAD command is issued.
2. When generating the absolute image form of files already loaded
into storage, make sure that the MAP option is in effect when the GENMOD command is issued. Since MAP is the default option, just be
sure that NOMAP is not specified. Issue the MODMAP command to type
the load map associated with the specified MODULE file on the
terminal. The format of the MODMAP command is: MODmap I filename
filename is the module whose map is to be displayed. The filetype must
be MODULE. Reading eMS Abend Dumps
If an abend dump is desired when CMS abnormally terminates, the terminal
operator must enter the DEBUG command and then the DUMP subcommand. The
dump formats and prints: General registers Extended control registers Floating-paint registers Storage boundaries with their corresponding storage protect key Current PSW Selected storage
Storage is printed in hexadecimal representation, eight words to the
line, with EBCDIC translation at the right. The hexadecimal storage
address corresponding to the first byte of each line is printed at the
left ..
68 IBM VM/370 System programmer's Guide
ihen CMS can no longer continue, it abnormally terminates. To debug CMS, first determine the condition that caused the abend and then find
why the condition occurred. In order to find the cause of aCeS problem, you must be familiar with the structure and functions of CMS. Refer to "Part 3: Conversational Monitor System (CMS)" for functional
information. The following discussion on reading CMS dumps refers to
several eMS control blocks and fields in the centrol blocks. Refer to
the VML11Q gDQ 1Qgi£ for details on CMS control
blocks. Figure 12 shows the CMS control block relationships. You will
also need a current CMS nucleus load map in order to analyze the dump. REASON FOR THE ABEND
Determine the immediate reason for the abend and identify the failing module. The abend message DMSABN148T contains an abend code and failing
address. The VML11Q manual lists all the CMS abend
codes, identifies the module that caused the module to abend, and
describes the action that should be taken whenever eMS abnormally
terminates. You may have to examine several fields in the nucleus constant area (NUCON) of low storage. 1. Examine the program old PSi (PGMOPSW) at location Using the PSi and current CMS load map# determine the failing address.
2. Examine the SVC old PSi (SVCOPSi) at location X'20'. 3. Examine the external old PSi (EXTOPSi) at location X'18'. If the
virtual machine operator terminated CMS, this PSi points to the
instruction executing when the termination request was recognized.
4. For a machine check, examine the machine check old PSi (MCKOPSW) at
location X'30'. Refer to Figure 47 in "Appendix A: System/370 Information" for a description of the PSi. Part 1. Debugging with VM/370 69
Previous Page Next Page