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* [TUHS] 6-bit, 7-bit and 9-bit byte UNIXes
@ 2004-09-30 19:07 Natalia Portillo
  2004-09-30 23:57 ` Greg 'groggy' Lehey
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Natalia Portillo @ 2004-09-30 19:07 UTC (permalink / raw)


Hi!

Was there any UNIX with 6-bit wide, 7-bit wide or 9-bit wide bytes or all
UNIXes are 8-bit wide bytes?

Regards



^ permalink raw reply	[flat|nested] 8+ messages in thread
* [TUHS] 6-bit, 7-bit and 9-bit byte UNIXes
@ 2004-09-30 23:46 James Petts
  0 siblings, 0 replies; 8+ messages in thread
From: James Petts @ 2004-09-30 23:46 UTC (permalink / raw)


Natalia

I don't know of any non-8-bit Unix systems, but Multics, on the GE645 at
least, had a 36-bit word. See

http://en.wikipedia.org/wiki/Multics

James


----- Original Message -----
From: "Natalia Portillo" <iosglpgc@teleline.es>
Date: Thu, 30 Sep 2004 20:07:46 +0100
To: <tuhs at tuhs.org>
Subject: [TUHS] 6-bit, 7-bit and 9-bit byte UNIXes

> Hi!
> 
> Was there any UNIX with 6-bit wide, 7-bit wide or 9-bit wide bytes or all
> UNIXes are 8-bit wide bytes?
> 
> Regards
> 
> _______________________________________________
> TUHS mailing list
> TUHS at minnie.tuhs.org
> http://minnie.tuhs.org/mailman/listinfo/tuhs



^ permalink raw reply	[flat|nested] 8+ messages in thread
* [TUHS] 6-bit, 7-bit and 9-bit byte UNIXes
@ 2004-10-01  0:47 Norman Wilson
  2004-10-01  1:05 ` Andru Luvisi
  0 siblings, 1 reply; 8+ messages in thread
From: Norman Wilson @ 2004-10-01  0:47 UTC (permalink / raw)


The very first UNIX ran on the PDP-7, which had 18-bit words.

I happen to have the assembly-language source code to parts
of that system.  Many programs contain error-handling code
that does something like this:

	lac d1
	sys write; 1f; 1
	jmp somewhere

1:	077012

	...

d1:	1

Evidently the system thought in words in those days
(the second argument to sys write is presumably a word
count), but the single word written is a strong clue
that 9-bit bytes were used, and that a certain concise
error message that people love to complain about was
there from the beginning (and why not?).

Norman Wilson
Toronto ON


^ permalink raw reply	[flat|nested] 8+ messages in thread
* [TUHS] 6-bit, 7-bit and 9-bit byte UNIXes
@ 2004-10-01  3:59 Carl Lowenstein
  0 siblings, 0 replies; 8+ messages in thread
From: Carl Lowenstein @ 2004-10-01  3:59 UTC (permalink / raw)


> Subject: Re: [TUHS] 6-bit, 7-bit and 9-bit byte UNIXes
> From: Norman Wilson <norman at nose.cs.utoronto.ca>
> To: tuhs at tuhs.org
> Date: Thu, 30 Sep 2004 20:47:22 -0400
> 
> The very first UNIX ran on the PDP-7, which had 18-bit words.
> 
> I happen to have the assembly-language source code to parts
> of that system.  Many programs contain error-handling code
> that does something like this:
> 
> 	lac d1
> 	sys write; 1f; 1
> 	jmp somewhere
> 
> 1:	077012
> 
> 	...
> 
> d1:	1
> 
> Evidently the system thought in words in those days
> (the second argument to sys write is presumably a word
> count), but the single word written is a strong clue
> that 9-bit bytes were used, and that a certain concise
> error message that people love to complain about was
> there from the beginning (and why not?).

?

I would say "the PDP7 computer was word-addressable".  In this
context, characters seem to have been packed as 9-bit half-words
in a big-endian fashion.  No 'bytes'.

Maybe tomorrow I will be near my DEC literature archives, and see
if I can find some clues about PDP7 instructions that might deal
with half-words.  If it's anything like the PDP8 of similar vintage,
there aren't any.  Late in its life the PDP8 got a BSW "byte swap"
instruction to swap the half-words in the AC register.  6 bits,
of course.

    carl
-- 
    carl lowenstein         marine physical lab     u.c. san diego
                                                 clowenst at ucsd.edu


^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2004-10-01  3:59 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2004-09-30 19:07 [TUHS] 6-bit, 7-bit and 9-bit byte UNIXes Natalia Portillo
2004-09-30 23:57 ` Greg 'groggy' Lehey
2004-10-01  0:21 ` Kenneth Stailey
2004-10-01  0:58 ` Michael Davidson
2004-09-30 23:46 James Petts
2004-10-01  0:47 Norman Wilson
2004-10-01  1:05 ` Andru Luvisi
2004-10-01  3:59 Carl Lowenstein

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