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From: Robert A Duff <bobduff@world.std.com>
Subject: Re: Streams in Ada
Sender: bobduff@world.std.com (Robert A Duff)
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Date: Fri, 13 Apr 2001 23:21:59 GMT
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Date: 2001-04-13T23:21:59+00:00
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Kilgallen@eisner.decus.org.nospam (Larry Kilgallen) writes:

> In article <wccg0frw5se.fsf@world.std.com>, Robert A Duff <bobduff@world.std.com> writes:
> > "Marin David Condic" <marin.condic.auntie.spam@pacemicro.com> writes:
> > 
> >> The PDP-10 was more closely oriented to "Sixbit" characters. (Or
> >> "Half-ASCII" - basically ASCII with the lower case & some other stuff gone.)
> >> IIRC, the Tops-10 OS had the 6x3 file name restrictions basically because it
> >> would make filenames fit with Sixbit & into even multiples of machine words.
> > 
> > This is more a property of Tops-10 than the PDP-10 hardware.
> > 
> > The hardware supported "bytes", which could be from 1 to 36 bits each --
> > there's nothing special about 6-bit bytes.
> 
> 6-bit bytes were adequate to meet the needs of the time.
> As I recall, ITS (Incompatible Timesharing System), which
> predated Tops-10, used 6x6 filenames.

You seem to be implying that "bytes" are always used to represent
"characters".  On the PDP-10, 6-bit bytes were used to represent 6-bit
characters, and 7-bit bytes were used to represent 7-bit ASCII, and
1-bit bytes were used to represent booleans, and 3-bit bytes were used
to represent enumeration types with 8 values, and so on.

- Bob