[ih] IBM ASCII, was Re: Impact of history on today's technology [was: why did CC happen at all?]

[Tony Finch]

John Klensin <jklensin at gmail.com> wrote:
>
> -- IBM's original System/360 spec specified ASCII as an alternative to
> EBCDIC, but their coding of ASCII put the seven bit code into an eight
> bit byte, not with a leading zero but with a parity bit in the middle.

That's loony, but reality seems to be even weirder! From the article below
it looks like they shifted the top two bits up one and put a copy of the
top bit in the gap.

http://www6.in.tum.de/pub/Main/TeachingWs2010Echtzeitsysteme/IBM360-Amdahl_april64.pdf

> I don't have firsthand experience with an installation that turned
> that coding on, but imagine it would have made other things worse.

I get the impression from http://www.bobbemer.com/P-BIT.HTM that it mostly
would not have worked.

Tony.
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