gtpi1m62System Installation Support Reference

Locating Global Areas in a Dump

To locate the start of the global areas for each subsystem user on each I-stream, you must interrogate the subsystem user table (data macro MS0UT). In a dump, the subsystem user table (SSUT) is labeled with the tag SSU. An address for this tag is provided in the dump label index at the end of the dump.

The first 4 bytes of the SSUT contain the number of subsystem users in the system. The SSUT contains one entry for each SSU.

The length of each SSUT entry is defined by the label MU0LEN in DSECT MS0UT. A header occupies the first 12 bytes of each entry. The header is used to identify each entry with a subsystem user and is laid out as follows:




The rest of an entry contains the addresses to each I-stream's unique primary and extended global areas as well as each I-stream's global attribute tables, as Figure 10 shows.

The formula for locating the address of any unique global area in a dump listing of the SSUT for any SSU/I-stream combination is:

          ADDRESS = START + S + G + I

where

START = address of the SSU tag + (MU0GLB - MU0CNT)

S = SSU number × MU0LEN

G = (global area number - 1) × MU0ASZ

I = (I-stream number - 1) × MU0GSZ

These variables are defined in terms of the following symbolic labels found in MS0UT:

Figure 10. SSUT Entry