For around 18 months I supported a card input validation suite that ran on a 24KB 360/25.
The backup system was a 360/50 under OS/360 MFT. The code was all written quite deliberately with this compatibility in mind, and it actually wasn't hard. The DOS system used split cylinders on 2311s and the OS system was file compatible - if the /25 died (which I don't think it ever did, but the building power did on many occasions) the pack was carted up to the /360. We noticed that formatting this full-pack split cylinder dataset took AGES under OS/360. It turned out that the /25 DOS system was stripped down as a single user system and the file masks permitted all seeks within a cylinder - even to the other dataset. The /50 set a file mask to inhibit all seeks - thus each track format cost two revolutions. -- Phil Payne http://www.isham-research.co.uk +44 7833 654 800 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
