Mainframe, MVS and zOS Discussion

Hi, I faced a scenario in real time today. I wrote a TLF ( Transaction Log File )extract program using COBOL85 on Guardian side which was working perfectly fine till now before being dumped coz of a huge amount of transactions for add new system.

Would like to get clarified on certain things.

1. Is possible create a file of such a huge size (PEXT 18000+) through Cobol programs? We got error 590 using FILE_CREATELIST_
2. What exactly is the reason behind this? Variable is 9(04) COMP we try to put 18000 this doesn't work.
3. I have used guardian procedures from Cobol. Any other alternatives for this?

1. Is possible create a file of such a huge size (PEXT 18000+) through Cobol programs? We got error 590 using FILE_CREATELIST_

I've never worked on a Tandem computer so I have no idea -- check with Tandem. On the IBM mainframe, the file size that can be created does not depend upon COBOL but rather the JCL (or other file creation method) parameters specified.

2. What exactly is the reason behind this? Variable is 9(04) COMP we try to put 18000 this doesn't work.

COBOL usually enforces the PICTURE size on values. On IBM mainframes, this can be bypassed using compiler options but only for COMP variables.

3. I have used guardian procedures from Cobol. Any other alternatives for this?

Consult your site Tandem expert since I theorize that "guardian procedures" are specific to Tandem machines (I've never heard that term before in reference to COBOL).

What are Tandem Computers? Are they mainframes?

Tandem makes fault-tolerant computers that compete well with large IBM mainframes. The architecture is very different from IBM's but they are still mainframe-scale systems.

Robert Sample wrote: Thu Aug 04, 2022 6:20 pm Tandem makes fault-tolerant computers that compete well with large IBM mainframes. The architecture is very different from IBM's but they are still mainframe-scale systems.

Thanks Robert. Do ATM machines use Tandem computers?

Although I don't know for sure, I would suspect that ATM machines do not use Tandem computers -- especially since Tandem NonStop computers almost always cost more than $1 million and that's a bit much for an ATM. ATM machines probably use some variety of microcomputer with Windows / Linux on them. ATM machines may connect to a Tandem computer, but the actual ATM will not be using the Tandem hardware or OS.