IBM Mainframe Discussion List <IBM-MAIN@BAMA.UA.EDU> wrote on 04/09/2008 02:16:58 PM:
> 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. > > Do I have any other options? Thanks so much. Is it necessary to concatenate all of the files? Could you restructure the program so that it allocates, opens, reads, closes, and unallocates each file sequentially? If the purpose is simply to read and process all of the records in all of the files, it would seem that this would accomplish the same objective, and the records would be processed in the same order. Jim Mulder z/OS System Test IBM Corp. Poughkeepsie, NY ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
