SPACE parameter in JCL.

[Mahesh Ayyar]

We have a Job which abended with SB37, for a file which has SPACE=(4095,(500,500),RLSE): my question is if I give the SPACE=(CYL,(500,500),RLSE), will that be a good change?

[Robert Sample]

Perhaps, but perhaps not -- what does your site's space management group say? The storage pool for your data set may not have enough free space to allocate 500 cylinders -- but that is something only someone working at your site can determine.

[Mahesh Ayyar]

I might be wrong but with SPACE=(4095,(500,500),RLSE) will not the allocation be in the multiples of bloacksize rather than a cylinder itself?

[Robert Sample]

Yes, SPACE=(4096,(500,500),RLSE) will allocate blocks not cylinders. Changing to cylinders increases the space being allocated by 180 times (15 tracks / cylinder times 12 blocks / track). If the SB37 ABEND is due to the data set reaching 16 extents, changing to cylinders may -- or may not -- resolve the space issue (for example, if the program is in an infinite loop with the WRITE statement in the loop, it is not possible to give the data set enough space, period). If the SB37 is due to the volume being out of space, then changing to cylinders will not affect the SB37 (and may cause it to occur faster if there is not enough free space to be able to allocate 500 cylinders in 5 extents).

[Mahesh Ayyar]

Thanks Robert.