[squeak-dev] Dorados (was: Efficient Implementation of the Smalltalk-80 System: what was the hardware?)

tim Rowledge tim at rowledge.org
Thu Jul 25 23:44:06 UTC 2019

> On 2019-07-25, at 3:50 PM, Jecel Assumpcao Jr. <jecel at merlintec.com> wrote:
> Tim Rowledge wrote on Thu, 25 Jul 2019 15:03:56 -0700
>> And by the end of '87 Eliot & I had his old BrouHaHa interpreter
>> running on a 4MHz ARM1 at 25% Dorado and an 8MHz ARM3 at 85%.
> Wouldn't that have been an 8MHz ARM2?

No, it was an ARM1, though looking up my notes reminds me it was a 6MHz cpu not 4MHz. No cache, not even any instruction prefetch but still much faster than anything from intel or motorola of that time.

> That is what is in my Merlin 4
> computer (which I tried to turn on the other day to demo to a visitor
> and it didn't work). The ARM3 was an ARM2 with 4KB of unified cache and
> could run at 24MHz.

Well, yes, ARM3 machines did eventually run up to ~25MHz but the one I had (actually, still have) was a hand built Acorn prototype that originally had the above ARM1 cpu, then got a board mod to run the cpu at 12 whilst the memory stayed at 8, and then a very complex bit of rewiring to put in an ARM prototype at 12MHz. The 4Kb cache made a huge difference. Oh, and both systems had a whopping, colossal, amazing *4* megabytes of memory!

tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
Strange OpCodes: HSJ: Hop, Skip and Jump

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