From: Tom Lyon <pugs@ieee.org>
To: Dave Horsfall <dave@horsfall.org>
Cc: The Eunuchs Hysterical Society <tuhs@tuhs.org>
Subject: Re: [TUHS] reviving a bit of WWB
Date: Wed, 3 Feb 2021 15:46:20 -0800 [thread overview]
Message-ID: <CAAOGWQgQ-c135GkE0CpupDLwJg57xVTAk-LOvJJYHSik+xMguw@mail.gmail.com> (raw)
In-Reply-To: <alpine.BSF.2.21.9999.2102040659560.70858@aneurin.horsfall.org>
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System/360s, or at least 370s, could do ASCII perfectly well.
When we started UNIX on VM/370, it was clear to us that we wanted to run
with ASCII. But some otherwise intelligent people told us that it *just
couldn't be done* - the instructions depended on EBCDIC.
But I think there was only 1 machine instruction with any hint of EBCDIC -
and it was an instruction that no-one could imagine being used by a
compiler,
Of course, plenty of EBCDIC/ASCII conversions went on in drivers, etc, but
that was easy.
On Wed, Feb 3, 2021 at 12:09 PM Dave Horsfall <dave@horsfall.org> wrote:
> On Wed, 3 Feb 2021, Peter Jeremy wrote:
>
> > I'm not sure that 16 (or any other 2^n) bits is that obvious up front.
> > Does anyone know why the computer industry wound up standardising on
> > 8-bit bytes?
>
> Best reason I can think of is System/360 with 8-bit EBCDIC (Ugh! Who said
> that "J" should follow "I"?). I'm told that you could coerce it into
> using ASCII, although I've never seen it.
>
> > Scientific computers were word-based and the number of bits in a word is
> > more driven by the desired float range/precision. Commercial computers
> > needed to support BCD numbers and typically 6-bit characters. ASCII
> > (when it turned up) was 7 bits and so 8-bit characters wasted ⅛ of the
> > storage. Minis tended to have shorter word sizes to minimise the amount
> > of hardware.
>
> Why would you want to have a 7-bit symbol? Powers of two seem to be
> natural on a binary machine (although there is a running joke that CDC
> boxes has 7-1/2 bit bytes...
>
> I guess the real question is why did we move to binary machines at all;
> were there ever any ternary machines?
>
> -- Dave
--
- Tom
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next prev parent reply other threads:[~2021-02-03 23:47 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-19 1:51 Doug McIlroy
2020-09-20 18:42 ` arnold
2020-09-20 19:28 ` Will Senn
2020-09-20 20:12 ` Steve Nickolas
2020-09-20 20:26 ` Doug McIlroy
2020-09-20 20:57 ` Doug McIlroy
2020-09-20 22:13 ` Clem Cole
2020-09-21 20:43 ` Steffen Nurpmeso
2020-09-20 20:58 ` Steve Nickolas
2020-09-20 21:33 ` Brantley Coile
2020-10-07 5:43 ` scj
2020-09-20 21:35 ` John Cowan
2021-02-02 23:08 ` Greg A. Woods
2021-02-02 23:47 ` Larry McVoy
2021-02-03 0:11 ` Dave Horsfall
2021-02-03 0:19 ` Larry McVoy
2021-02-03 2:04 ` Richard Salz
2021-02-03 3:32 ` Dave Horsfall
2021-02-03 4:32 ` M Douglas McIlroy
2021-02-03 11:27 ` Peter Jeremy via TUHS
2021-02-03 20:09 ` Dave Horsfall
2021-02-03 20:13 ` Niklas Karlsson
2021-02-03 23:46 ` Tom Lyon [this message]
2021-02-03 22:19 ` Dave Horsfall
2021-02-03 22:55 ` M Douglas McIlroy
2020-09-20 22:15 ` Clem Cole
2020-09-20 22:47 ` John Cowan
2020-09-21 20:48 ` Steffen Nurpmeso
2020-09-21 20:46 ` Steffen Nurpmeso
2020-09-24 2:25 ` Dave Horsfall
2020-09-24 2:33 ` Clem Cole
2020-09-25 0:18 ` [TUHS] One's complement (was: reviving a bit of WWB) Greg 'groggy' Lehey
2020-09-25 0:22 ` Warner Losh
2020-09-25 1:39 ` John Cowan
2020-09-27 5:54 ` [TUHS] reviving a bit of WWB Dave Horsfall
2020-09-24 17:19 ` Paul Winalski
2020-09-24 18:17 ` John Cowan
2020-10-07 5:47 ` scj
2020-10-07 9:20 ` arnold
2020-10-08 0:27 ` Dave Horsfall
2020-10-08 3:08 ` John Cowan
2020-09-20 22:51 Norman Wilson
2020-09-20 23:00 Norman Wilson
2020-09-20 23:53 ` Clem Cole
2020-09-21 0:00 ` Clem Cole
2020-09-21 2:24 ` John Cowan
2020-09-21 0:09 ` Warner Losh
2020-09-21 1:05 ` Clem Cole
2020-09-21 5:55 ` Steve Nickolas
2020-09-21 5:59 ` Warner Losh
2020-09-21 18:40 ` Paul Winalski
2020-09-21 19:56 ` Dan Cross
2020-09-21 20:50 ` John Cowan
2020-09-21 21:22 ` Rob Pike
2020-09-21 21:57 ` Clem Cole
2020-09-21 23:56 ` John Cowan
2020-09-22 0:54 ` Richard Salz
2020-09-21 21:39 ` Steve Nickolas
2020-09-25 14:19 Doug McIlroy
2020-09-28 17:35 ` Angelo Papenhoff
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