>The IBM 1620 used decimal arithmetic with 4 bit bytes limited to digits 0-9 >and plus and minus signs and what was effectively a space marking the end of a >number. It was called BCD coding.
I used to teach Binary Coded Decimal to my students. It was basically a shortcut, half Binary and half Decimal. You had four-bit words, but they were only 0-10 (0000 - 1010) If we cannot afford to take care of Veterans, then we should stop making them. David C. Wilker Jr. USAF (RET) On Thu, Dec 3, 2009 at 18:24, WhyOSX <[email protected]> wrote: > Yes, 360 was the system they sent the Apollo project up with. > The other IBM things are unknown to me. > Born in '63 I've seen an after WW II world - > we'll have to learn, always have to... > >>My first machine was a Control Data 1604 in 1961. Six bits per byte and 7 >>track tape with a bit for odd parity. Programming was done in octal. All caps >>FORTRAN came soon after. >> >>IBM introduced system 360 circa 1965, the full circle of computing capability. >>That came with 9 track tape and 8 bit bytes. Hexadecimal became the rule and >>the alphabet acquired lower case but ASCII only defined 7 bits out of the >>eight. EPSIDC character coding was an IBM-only thing and I probably spelled it >>wrong. >> >>The IBM 1620 used decimal arithmetic with 4 bit bytes limited to digits 0-9 >>and plus and minus signs and what was effectively a space marking the end of a >>number. It was called BCD coding. >>which was used a lot in the 360's and later with two digits per 8-bit byte. >> >>As for current technology, there are still ASR33-like teletype machines >>around. They are 5 bits per byte. >> >>RYRYRYRYRYRYRYRYRYRYRYRY >>-- >> >>--> From the U S of A, the only socialist country that refuses to admit it. > > -- > ----- > You received this message because you are a member of the Vintage Macs group. > The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our > netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml > To post to this group, send email to [email protected] > To leave this group, send email to [email protected] > For more options, visit this group at > http://groups.google.com/group/vintage-macs > > Support for older Macs: http://lowendmac.com/services/ > -- ----- You received this message because you are a member of the Vintage Macs group. The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To leave this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/vintage-macs Support for older Macs: http://lowendmac.com/services/
