[Info-vax] Unix on A DEC Vax?

[Bill Gunshannon]

In article <0f9cc4f1-9f32-4d3a-9ad6-0dcaa0c2e59a at googlegroups.com>,
	"Stanley F. Quayle" <stanley.f.quayle at gmail.com> writes:
>> My cell phone probably has significantly more computing power and far more memory and storage than this "minicomputer",
> I have SIMH on my Android phone.  Fun to work with, but not really practical -- it doesn't access the WIFI network interface.  If it did, it could be useful, sort of.

I never saw the purpose in this other than, "Look what I can do!"

>> And the time needed to run a particular CPU test on an emulator will always reveal that it is slower than running native code on the host CPU.
> Would you expect an emulator to test as *faster* than native code?

Well, first of all, all of the emulators I know of do not emulate CPU,
per se, they emulate entire systems which just happen to have a CPU
that needs to be emulated, too.  E11 isn't a PDP-11 CPU emulator it
is an entire PDP-11 system emulator.  Big difference.  Same with SIMH.
And, yes, when emulating 20 (or more) year old systems I would expect
the emulator to be faster.  Trying to emulate something (Alpha) which
is still very common in production use is another matter.  SIMH is the
fastest IBM 1401 I have ever seen.  :-)

>> Having seen the speed of shadow copies under SimH and the free Alpha
> emulators the improved disk speeds are no surprise.  Is the full backup
> time for CHARON-VAX quoted on your web page to tape or disk?
> As I recall, he's backing up to virtual tape.  That becomes a file in Windows, which is then archived to storage elsewhere using standard Windows tools.
>> eat a CPU
> True, emulating a different processor is a full-time job.  CHARON comes with a "slowdown" kernel widget that stops the interpreter when the emulated CPU is idle.  I've read discussions about SIMH doing the same thing, although I don't know if it ever came to pass.

Been there for quite some time now.

bill

-- 
Bill Gunshannon          |  de-moc-ra-cy (di mok' ra see) n.  Three wolves
billg999 at cs.scranton.edu |  and a sheep voting on what's for dinner.
University of Scranton   |
Scranton, Pennsylvania   |         #include <std.disclaimer.h>