Right, I had found it there right after Doug's refresh of my memory. Many thanks to you both. I grab a copy and put it in my own historic archives. Clem http://bitsavers.org/pdf/regnecentralen/RC_4000_Reference_Manual_Jun69.pdf ᐧ On Sat, Mar 9, 2019 at 3:03 PM Bakul Shah wrote: > On Sat, 09 Mar 2019 14:19:43 -0500 Doug McIlroy > wrote: > > Clem, > > > > I think the "Algol machine" you have in mind is the RC-2000 (not quite > sure > > of the designation--could look it up in the attic if it matters) > designed by > > Per Brinch Hansen for Regencentralen (again, the name may not be quite > right). > > I believe he architected and wrote the OS for RC-4000. > > > The manual used Algol as a hardware description language. The > instruction > > set was not unusual. It has come up before in TUHS. I have the manual > > if you need more info. > > This manual is at bitsavers. >