Re: Why I've Dropped In

On Sat, 14 Jun 2025 19:23:59 +0000, Stephen Fuld wrote:

That is precisely my point.  The mechanism that IBM chose effectively
*prevents* program relocation.  That is why I believe it was a mistake
to choose that mechanism.

It prevents relocation of programs currently in use that are already in
memory.
It facilitates loading programs from object files on disk into any
desired part of memory, which is the usual meaning of "program
relocation" among System/360 programmers, perhaps because they had no
other type of it available.
Implementing the 360 architecture with the addition of a base and bounds
mechanism instead of full-blown virtual memory was perfectly possible.
However, the System/360 was originally conceived as a computer for use
in batch processing. Hence, TSS/360 was a kludge and ran slowly, and it
took the 360/67 with special hardware to facilitate timesharing for IBM
to have something that addressed that function effectively.
John Savard