This was in the late 80s when (slow) XTs where still very common. I recall running software like PSPICE and WordPerfect without much trouble.
The processor emulated was a 80188 (not 80186 as I mentioned earlier), which was used in the XT line of PCs. So comparing it with an AT PC is a bit unfair. I do think it was quite an achievement to emulate a processor at close to the same speed in software.
Of course I had bought the Acorn Archimedes for its ARM processor; I did program in assembly back in the day, and loved the very simple but powerful instruction set. Anyway, thanks for the link. I am quite sure I read the original back in the day.