22 Apr
2016
22 Apr
'16
1:38 p.m.
The way one would implement such accelerator boards over an IO subsystem
bus is to use memory-mapped registers and depending upon the accelerator
either a single register that executes an instruction on write or a
small memory for microcode with some way of triggering execution.
Older SGI's have a VME bus and the GIO/GIO64 bus used for I think the
Indigo's is also documented. This is aside from E(ISA) and PCI cards.
So it is possible but as mentioned before the software is an issue,
especially if you don't want to explicitly write code for it but have
the compiler automatically use the accelerator.
On the topic of IRIX emulation:
There used to be an emulator from Stanford which could run IRIX 5.4
https://en.wikipedia.org/wiki/SimOS
Also whilst searching for the latter's name I've found
https://www.vanheusden.com/miep/
(also Gxemul can emulate the PROM firmware of an O2)
- Jan
On 04/22/2016 09:12 PM, Swift Griggs wrote:
On Fri, 22 Apr 2016, Guy Sotomayor wrote:
[...] emulation (or dynamic translation) is fast
enough and with the
various virtualization capabilities, it?s not unusual to have multiple
different OS?s running on the same HW.
Indeed. My other wish is that someone far brighter than I will someday
develop a MIPS emulator capable of emulating IRIX. The odds of that aren't
great since untangling the ROM would be a real PITA.
Apple did this with some success in it?s various
CPU transitions. When
they switched from 68K to PPC, the PPC emulated the 68K code. The same
happened when they switched from PPC to x86, again the PPC code was
emulated (actually in that case it was dynamically translated).
Yes, and don't forget the NeXT platform which had "quad-fat binaries"
capable of running on 4 (!) platforms at once. It might have been a little
top heavy and impractical at times, but it was soooo cool to me. I'm sure
you remember "Rosetta" too. IRIX on x86 would be heresy to some, but I'd
welcome it *especially* if it could dynamically translate MIPS ECOFF
binaries, and run legacy IRIX software. I know the lawyers would never let
any of that happen, but a man needs to have some dreams. :-)
It?s also keeping in character with the old
machines. It?s not adding new
capabilities but more replacing old peripherals with something a bit more
convenient.
I see your point and I agree.
Adding in a new accelerator means not only
developing the HW but also
writing a boatload of *new* SW in order to be able to take advantage of
it.
An oil-tanker sized boat. Yep. Unless of course you could keep everything
pin compatible etc... which is even harder. "We're gonna need a bigger
boat."
Most of what you see (and what I?m mainly doing
these days in terms of
?hobby?) is producing parts to a system in order to keep it running rather
than adding completely new capabilities.
Well, I appreciate that fact that anyone is doing anything! If I ever
meet "Lotharek" I'm definitely buying him a round. I get excited just
looking at some old gear that someone's cleaned up nicely or polished the
face panels on. I'd probably die in an apoplectic fit if I ever saw an ad
for an SGI accel board. If I ever make someone mad, they could totally get
back at me by handing me a fake flyer for "Press release: Acme Inc
releases SGI MIPS accelerator board based off high speed GPU". When I
found out it was bogus I'd go jump off the roof. Joking aside, I do see
your point about restoring vs enhancing, and it's well taken.
Most companies would rather spend their time
and budget doing things for
a high ROI and for large and growing markets.
Amen brother, I was just wishing out loud. I needed someone to bring me back
to Earth.
-Swift