[HECnet] AXP Emulation

[Paul_Koning at Dell.com]

That's a good question.

For example, how does the SIMH pdp11 compare to E-11?   I can't make a direct comparison, unfortunately.

I did notice that SIMH vax seems surprisingly slow, at least when running NetBSD.

Another data point: dtcyber (a Cyber mainframe emulation) runs quite fast.   I haven't tried to express it in MIPS, or VUPS (or CUPS?) but it's much faster than the original hardware, which was in the 3-10 MIPS range.   So it seems to be closer to what you saw for Hercules.   And a Cyber is not that easy to emulate, due to its oddball floating point.

	paul

On Aug 9, 2012, at 4:07 PM, Sampsa Laine wrote:

Why is SIMH so slow though?

As far as I can understand, one MIPS is roughly one VUPS, correct?

So how come I get 14 VUPS on the same host running SIMH whilst my Hercules install peaks at 180?

Are the architectures that different (obviously they are) or what is it?

Sampsa


On 9 Aug 2012, at 23:04, Dave McGuire wrote:

On 08/09/2012 02:33 PM, Paul_Koning at Dell.com wrote:
This seems like a natural for SIMH, since it already has a large
amount of necessary prerequisites (a lot of device emulation,
framework pieces, etc.).

There is Alpha support in the development track version of simh.

Is the architecture well enough defined in
publicly available documents?   I would guess yes but I don't know for
sure.   Are there secret bits that are critical and hard to obtain?

The architecture manual pretty fully documents it.

                -Dave

-- 
Dave McGuire, AK4HZ
New Kensington, PA