The questions is very general. Let's look into these possibilities:

1. QSAM (sequential) file. You can run it thru SORT utility adding SEQNUM and then sort then sort by SEQNUM in DESC order

2. VSAM: In CICS you can read backward using READREV; i

3. VSAM: I Batch unload the VSAM file using SORT in DESC order by

key value

Hope that helps

Hi

It is possible through jcl. For example if the input file contains 80 record length then

In sort INREC (1:1 80 81:SEQNUM 6 ZD) SORT FIELDS (81 6 ZD D) OUTREC (1:1 80)

1) Using inrec we need to generate the sequential number starts from position 81.

For example

1) First 1-80 bytes contains the actual record and from position 81 we need to generate sequential number using inrec i.e 000100 000200 upto 50 records.

2) After generating all those numbers sort we takes place in descending order.

3) Using outrec we have to move the first 80 bytes to the output file.

After doing this sort in first step in jcl you can read the output file in second step

Thanks

Karthikkumar.P