Mainframe, MVS and zOS Discussion

The difference only appears when dealing with multiple job streams. Example: job A triggers job B triggers job C. At the same time, there is a different job stream where job D triggers job E triggers job F. Job B has a successor job of job F. If job E gets done at 11 AM and job B runs until 12 noon,...

Check out file 321 on the CBT tape (http://www.cbttape.org" onclick="window.open(this.href);return false;) for a program that can analyze COBOL load modules and give you information about them such as compiler used and compile options. You are also over-simplifying the history of COBOL on ...

Your post is not clear about what you need help with. The answer to your question is Yes, REXX can access a PDS. The simplest way is if you want to read a member of the PDS, allocate the data set name with member name and let REXX handle the read as if it were sequential. If you want to write to a m...

Consider the internal reader. You copy a series of JCL statements to it, and the internal reader buffers them in your address space. These JCL statements may include one job, or two jobs, or many jobs. Finding a JOB statement in the stream of statements indicates that the previous job (if any) is co...

Would MVS 3.8 on Hercules count? <g>

Executing STOP RUN in a CICS program would bring the entire CICS region down. GO BACK or EXIT PROGRAM merely return to the calling program (operating system for a batch program or CICS for a CICS program). So they are not exactly synonyms. There are still many program that have STOP RUN in them -- n...

Ask your site support group. They will know. If you're wanting to know if there is any way in general of knowing (from looking at data sets for example), then the answer is no. Although COBOL typically installs into version-specific data sets such as IGY.V5R1M0.SIGYCOMP, many sites use a non-version...

If you are talking about memory swaps (such as paging to / from auxiliary storage), the unit used is a page. And a page is 4096 bytes (4KB or 1024 words).

In general, anyone concerned about performance in this day of executing tens of millions to hundreds of millions of COBOL statements per second of CPU time is extremely misguided -- except for the one case where the program is already in production and not meeting batch window requirements. So the w...

You need to find the File Aid manuals at your site (if your site is licensed for File Aid, you have access to the manuals, via harcopy at your site or internal web site or through the vendor web site) and read up on this. Or you could try the online help by hitting F1 after doing option 7 for XREF f...

The answer to your question partly depends upon what you mean by "better for calculation". For general calculations, using COMP-3 (packed decimal) is usually better than DISPLAY (zoned decimal). For some calculations, using COMP (binary) will be better than COMP-3 or DISPLAY. The -9(9) is ...

If the job failed for an allocation problem, then it never got started executing. In that case, restart and resubmit would be the same. As I stated in my previous post, "restart" is an ambiguous term since it can refer to multiple things. Without knowing the type of "restart" bei...

If the data set has about 2 billion records, I would NOT recommend using REXX.

Link list applies only to load libraries. Hence copy books cannot be stored in the link list.

I don't think using SORT would allow one to empty a VSAM file. A program could, by reading each record sequentially and then deleting that record. I'm not sure if sorting an empty file into the VSAM file would delete the records or not.

It can be MUCH higher than that. Job management is generally handled by Workload Manager (WLM) these days. There are 6 priority classes for a job in WLM -- 1 through 5 and DISCRETIONARY. A discretionary job gets CPU time if -- and only if -- no other job with a numeric priority can use the CPU time....

The system determines the start of a job when it finds a JOB card. The end of the job is much harder to determine, but a new job card definitely ends the previous job. The member count of a PDS has nothing to do with the number of submitted jobs.

Yes, the region shown on the log on screen is the memory size allowed. There is some overhead with the system so if the value is 256000 then you cannot actually edit a file that contains 256,000 K of data.

Under z/OS, there are typically hundreds of tasks running simultaneously on any given system. These include started tasks (which would include DB2, MQ series, Websphere, system tasks), TSO users, batch jobs, CICS regions. The system manages these tasks and allows each to run for a certain amount of ...

From the z/OS Concepts manual: Swapping is the process of transferring all of the pages of an address space between central storage and auxiliary storage. A swapped-in address space is active, having pages in central storage frames and pages in auxiliary storage slots. A swapped-out address space is...