Bob, Earlier than the IBM 650, the Burroughs 205 used the same principle. Words were recorded (20 of them on each band) on a drum, and with careful programming you could accomplish the same thing you mentioned. I worked on them for a long time (1959-64) and wrote some very complicated chemical equilibrium programs totally in machine language! John -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of Bob Ammerman Sent: Wednesday, May 25, 2005 8:46 AM To: Microcontroller discussion list - Public. Subject: Re: [OT] Historical Computer Triva > At 03:11 PM 5/24/2005, Bob Ammerman wrote: >What successful computer system used decimal arithmetic with numbers >represented in biquinary? The answer I was looking for was the IBM 650. This was one of the first highly successful computers to be developed by IBM, and is considered by many to have been the first 'personal' computer. In additional to its unusual way of displaying decimal digits, it had a couple of very interesting characteristics... - Initially all input and output had to be via punched cards or magnetic tape. If you wanted a printed report it had to be generated by an offline tape-to-printer or card-to-printer device. - Its main storage consisted of a rotating drum with 20000 addressable 10-digit (?) words of memory. - Instructions were not executed sequentially. Rather each instruction contained the address of the next instruction to be executed. In effect, each instruction was a 'jump' instruction as well as its ordinary function. - By carefully placing instructions around the drum you could time things so that the next instruction would be under the read head just as the previous instruction finished executing. - Eventually some smart programmer realized that the computer itself could do the job of optimizing the placement of instructions and so was born SOAP, the Symbolic Optimal Assembly Program. - However, some 'real programmers' wouldn't use SOAP because they felt they could do a better job hand-optimizing the code. Some things never change ;-) Truly a fascinating machine. Bob Ammerman RAm Systems ----- Original Message ----- From: "Jake Anderson" To: "Microcontroller discussion list - Public." Sent: Wednesday, May 25, 2005 7:54 AM Subject: RE: [OT] Historical Computer Triva > larc? > >> -----Original Message----- >> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]On Behalf >> Of Bob Ammerman >> Sent: Wednesday, May 25, 2005 09:58 >> To: Microcontroller discussion list - Public. >> Subject: Re: [OT] Historical Computer Triva >> >> >> Dave, >> >> Very good answer, but what I was looking for was a little newer than >> that. >> >> Bob Ammerman >> >> ----- Original Message ----- >> From: "Dave VanHorn" >> To: "Microcontroller discussion list - Public." ; >> "Microcontroller discussion list - Public." >> Sent: Tuesday, May 24, 2005 4:26 PM >> Subject: Re: [OT] Historical Computer Triva >> >> >> > >> > After the abacus? >> > >> > -- >> > http://www.piclist.com PIC/SX FAQ & list archive >> > View/change your membership options at >> > http://mailman.mit.edu/mailman/listinfo/piclist >> > >> >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist