I have a mainframe assembler application which is invoking Unix system
services to get the names of all of the files in an NFS-mounted folder. The
application dynamically allocates and logically concatenates these files into
one giant dataset, then uses QSAM macros to read it.
The DYNALLOC calls work this way: first, I dynamically allocate the first file in
the folder with DDNAME MYFILE. Then the program enters a loop, performing
these steps for each remaining file in the folder:
1) Dynamically allocate the file, asking the system to provide the DDNAME (I
observe that these are getting the ddnames SYS00001, SYS00002, etc).
2) Dynamically concatenate MYFILE with the SYSxxxxx dataset just allocated
(with the “permanently allocated” attribute on).
This works beautifully; when I exit the loop, I can OPEN and GET all the
records successfully from MYFILE.
The problem is that I have reached a practical limit of approximately 540 files
in the folder, because when I reach that point, I get a dynamic concatenation
ABEND due to the TIOT filling up. I am told that our TIOT size is the default of
32K, which would allow for a maximum of 1,635 DDs in a job step. It would
seem, however, that something in my allocation/concatenation loop is
preventing me from reaching that number of files. There are only a handful of
other DDs allocated to the step (e.g., STEPLIB, etc).
If I were able to handle up to 750 (or perhaps 1,000) files at a time, it would
be of immense help. At the moment, our only option seems to be to split up
the files into multiple folders of 500 files each.
