10 Mar
2023
10 Mar
'23
5:01 p.m.
On 3/10/23 13:00, Paul Koning via cctalk wrote:
MFT was Multiprogramming with a Fixed number of Tasks, MVT
was Multiprogramming with a Variable number of Tasks. MFT
had "fixed" partitions, although the operator could "drain"
partitions and then rearrange them manually. MVT
automatically rearranged partitions by looking at the memory
requirements of the next-up programs in the queue. Well,
that all sounds great, except that allowing the user to ask
for completely random partition sizes ended up filling
memory with little chunks of odd-size partitions that left
memory fragmented. So, the fix was to only allow partition
sizes in some standard quanta like 50 K. If you asked for
37 K you would run in a 50K partition and be charged for it.
MVS was a 370 OS.
Jon
On Mar 10, 2023, at 1:38 PM, Chuck Guzis via
cctalk <cctalk(a)classiccmp.org> wrote:
On 3/10/23 10:20, Bill Gunshannon via cctalk wrote:
You mean
DOS/360 as opposed to OS/360? I don't know that one. But OS/360 came in three
flavors: PCP, MFS, and MVS. The first mainframe I worked on was single user,
single tasking.
S/360 DOS provided for one "background" memory partition
and two
"foreground" ones. Batch submissions would be background, with some
installations using the smaller foreground ones for interactive use.