MVSFORUMS.com

[enge]

goodmorning,
how many kb are there in a cyl ? and in a trk?

[Bill Dennis]

It depends on device type and blksize used. The DASD devices have some amount of overhead in leaving logical "gaps" between blocks of data. Larger blocksizes mean higher utilization. Half-track blksize is recommended. Also for PDS the actual member sizes affect the KB per trk (again because the data blocks may be smallish). VSAM utilization depends on record sizes, freespace, splits, etc.

The 3390 Reference Summary (GX26-4577) will show utilization at various blocksizes. Look for this manual.
Sample:
3390 (half-trk) = 27998 bytes if your block fully uses the space.

Double this for full track. Multiply by 15 for cyl.

Regards,
Bill

[enge]

thanks very very much