IBM Mainframe Forum

Hi Guys

I am new to IMS. So need to know regarding GSAM files. and how to access/browse an existing GSAM. Do we need to login to IMS to access them...?? basically all I want to know is starting from creating a GSAM till creating one and have records written onto it.

thanks
venu

GSAM files are ordinary sequential files. You can create and read them like any other sequential file. To access them via IMs you need to provide IMS with information. I suggest you click the manuals link, select the IMS programming guide, search for GSAM and start reading.

To use with an IMS program, a GSAM needs to be in that program's PSB. That's the thing that tells a program which databases/segments it can use. A GSAM file needs to have DBD (database definition) so that it can be included in a PSB. The DBD will say something like "sequential file, lrecl=100, DDname for inut, DDname for output" The PSN definition will allow for read-only (Get Sequential) ((GS)) or for writing (Load Sequential)((LS)) by using the correct ProcOpt.

I've never used a GSAM file in the online region, I'm not even sure it's possible. I always use them in batch jobs. You SHOULD do an OPEN call and a CLOSE call when working with them. You use ISRT and GN to write/read them.

If you are doing a restart (XRST) call, make sure you DON'T do an OPEN call on the GSAM, because it will reset the pointer to the beginning of the file.

Hi Guys

Thanks for all info...I wanted another info. to browse the content of GSAM file.
In MF we access the normal flat/any other files with 3.4 opt and then browse(B) the file to see the content. like that, want to know how to browse a GSAM file and see the content in it.

thanks
venu

the topic title reflects a misunderstanding ...

GSAM is NOT the dataset organization or a file type ( as seen from the zOS point of view ) ....
it is a DATABASE organization as seen by IMS to process it according to a subset of IMS DB rules
- mostly regarding data-integrity and checkpoint-restart

from the zOS point of view it is just a good old plain PS file and You can browse it using ISPF

Why have you not tried browsing it either through 3.4 and browse option or via option1 - Browse?