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From: bqt@update.uu.se (Johnny Billquist)
Subject: [TUHS] DEC filenames
Date: Sat, 26 Mar 2016 22:29:15 +0100	[thread overview]
Message-ID: <56F6FF2B.4070001@update.uu.se> (raw)
In-Reply-To: <20160326210306.GC12921@mercury.ccil.org>

On 2016-03-26 22:03, John Cowan wrote:
> Johnny Billquist scripsit:
>
>> SIXBIT dominated here for a long time. We see it both in the PDP-8,
>> but also the PDP-6 and its follow ons. RAD50 was the natural
>> extension of SIXBIT on a machine that did not have a word size that
>> was a multiple of 6.
>
> Well, for identifiers, yes.  But SIXBIT was quite general, especially
> if you repurposed two of the characters to mean "end of string" and
> "CR+LF".  The "@" was a popular choice for the former, perhaps because
> its encoding is 00; IIRC, "_" was popular for the latter.

Well, I was talking filenames (as also the subject says)... :-)

On the PDP-8, you sometimes saw @ used as a prefix character in SIXBIT. 
So you'd use @M to get a CR, and @J for an LF, and @@ would mark the end 
of the string. But not for filenames. But in code, since you sometimes 
used SIXBIT for string constants as well.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol


      reply	other threads:[~2016-03-26 21:29 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <mailman.163.1459021419.15972.tuhs@minnie.tuhs.org>
2016-03-26 20:30 ` [TUHS] DEC filenames (was: Command-line options) Johnny Billquist
2016-03-26 21:03   ` John Cowan
2016-03-26 21:29     ` Johnny Billquist [this message]

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