Back in the late seventies computers were still considered rather esoteric and in British Universities it took a lot of special pleading to be able to purchase one. Jodrell Bank Observatory already had a Ferranti Argos machine but were so not permitted to buy another so they decided to build a clone. As an ICL trained whizz kid designer I joined them on the project. We used AMD2901 bit slice chips,, 4K static memory chips, microcode in PROM. We even designed our own visual display unit. WE built on 2 sided circuit boards about 6" x 8 " plugged into a wire wrapped "back plane". It was surprisingly successful and we developed it to a fairly high degree of sophistication despite some severe engineering problems when we cranked the clock speed up. We also developed a version of the Forth language to run on it though a lot of the programming was done in machine code without even the benefit of mnemonics.. i still remember that 0200 was an unconditional jump And, yes, we also used teletypes with paper tape readers :-) __________________________________________ David C Brown 43 Bings Road Whaley Bridge High Peak Phone: 01663 733236 Derbyshire eMail: dcb.home@gmail.com SK23 7ND web: www.bings-knowle.co.uk/dcb *Sent from my etch-a-sketch* On 18 April 2018 at 08:26, DrSkip wrote: > Anyone build with TI 74181's and make their own CPUs? Static RAM > measured in k... Creating one's own microcode and "assembly language" > from scratch? Been there done that. 1970's... Long live wire-wraping! > ;) Wish I never had given away my teletype with paper tape reader! > > I could route one of the logs (Linux) to it (one without much activity > of course) and have it clank and tap away randomly throughout the day > and have a 1970 moment! > > > On 04/17/2018 07:34 PM, RussellMc wrote: > > On 16 April 2018 at 04:28, sd211 wrote: > > > > > >> Pentiums are kind of a new thing, not sure it will stick though. I > >> remember > >> the time when '386 was a leap forward! > >> In the "good old days" (tm), we had a 'Turbo' button on the computer, = so > >> you > >> can run the CPU at 1.5 - 2x speed. I think it was in PC XT and PC AT > >> computers, but my memory bank might be failing... > >> > > > > Uphill both ways in the snow, with no shoes ... cardboard box , ice, > pond, > > ... . > > > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .