That's fantastic. 4Mb of RAM in 1983 was pretty cool.

So the end product was somewhat like a homebrew second processor unit for a BBC?

e.g. http://chrisacorns.computinghistory.org.uk/8bit_Upgrades/Aco...

There were things I could read about in magazines as a kid but never got to see in the flesh. That Cambridge Workstation is still a mythical beast to me.

Note to self: go and visit the http://www.computinghistory.org.uk/det/897/Acorn-Computers/