Finding first-failure data capture data
You can use the tips in this topic to locate first-failure data capture (FFDC) data on the IBM® i operating system. The information is most useful if the failure causing the FFDC data output occurred on the server. The FFDC data for a client can usually be found in one of the spooled files associated with the job running the application program.
The Display option gives 16 bytes per line instead of 32. This can be useful for online viewing and printing screens on an 80-character workstation printer. If you choose the Display option, use F6 to see the hexadecimal data after you press Enter.
The hexadecimal data contains the first one KB of the FFDC dump data, preceded by some other data. The start of the FFDC data is identified by the FFDC data index. The name of the target job (if this is on the server) is before the data index. If the FFDC dump spool file has not been deleted, use this fully qualified job name to find the spool file. If the spool file is missing, either:
- Use the first one KB of the dump stored in the error log.
- Re-create the problem if the one KB of FFDC data is insufficient.
When interpreting FFDC data from the error log, the FFDC data in the error log is not formatted for reading as well as the data in the spooled files. Each section of the FFDC dump in the error log is prefixed by a four-byte header. The first two bytes of the header are the length of the following section (not counting the prefix). The second two bytes, which are the section number, correspond to the section number in the index.