How was simh compiled? I used Visual C and the difference between running the compiler with optimization on or off made quite a difference for the generated code. And gcc might compile even faster codefiles. Hans -----Original Message----- From: Sampsa Laine <sampsa at mac.com> Sender: owner-hecnet at Update.UU.SE Date: Thu, 09 Aug 2012 23:07:24 To: <hecnet at Update.UU.SE> Reply-To: hecnet at Update.UU.SESubject: Re: [HECnet] AXP Emulation 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