On Jan 8, 2008, at 1:19 PM, Phil Payne wrote:
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,
Thanks... do you remember which release of MFT this was? Did MFT do
the split cylinder data set creation?
Ed
----------------------------------------------------------------------
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
