29 Oct
2010
29 Oct
'10
9:31 a.m.
On 29 Oct 2010 at 0:11, Johnny Billquist wrote:
Next question: Does the VAX not have virtual memory
any more now that
I've pointed this out? Or do you need to redefine virtual memory in
yet a new and strange way to exclude the PDP-11... :-D
I think that using memory address spaces to qualify the "virtualness"
of memory is following the wrong animal.
I would define "virtual memory" as the ability to fool a program into
thinking that it has more physical memory than is actually present.
So, can a PDP-11 with 16K of memory appear to a program as if there
were 32K present?
All of this reminds me of the big rollout of the S/370 DAT systems
with virtual memory support and the marketing hype about not needing
to spend money on expensive memory. When some customers complained
that the performance under load of the 67 wasn't very good, IBM
responded that they needed to buy more memory...
--Chuck