CYBER word length

[Kim DeVaughn]

In article <254 at bsdpkh.UUCP>, latham at bsdpkh.UUCP (Ken Latham) writes:
> > And then they discovered that people would use more than 64 symbols, and
> > had to come up with an escape kluge to get additional symbols.  So now
> > CDC Display Codes can be either 6-bits or 12-bits in length.
> 
> 	CDC  uses prefix characters for additional display codes in
> 	much the same way that ANSI uses ^[ to prefix an incoming
> 	(outgoing) control string.
                   ^^^^^^^^^^^^^^
> 	You could no more say that ^[[2J  (ANSI clear screen) is
> 	32-bits long, than you can call CDC codes 12 bits long.
> 
> 	CDC sends one of several prefix codes ( micro, super, sub, shift ... )
> 	to apply to the following character ( sometimes combined they
> 	affect more than one character )

No, I wouldn't say <CSI>2J is a 32-bit character.  It is, as you pointed
out, a *control string*.  I find that to be quite different than the
basic character set a machine uses to represent textual information.
When the "A" character is 6 bits, and the "a" character is 12 bits, I
would still say that the character codes are either 6-bits or 12-bits.

> 	This is definitely NOT a KLUDGE !!!  It is a valid way of extending
> 	display codes.  It is far better than extending the bit length
> 	to include one number for each display alternative you have.

Sure, it's valid, but it sure makes writing things like a driver for a
Tektronix 4010 Graphics Display "interesting";  the CPU code was fairly
straightforward, but the PP code was a real mess.  And that was a *direct*
result of the 6/12-bit character set, which is why I call it a Kluge.
This was on a 6600 back in the early-mid 1970's ... the newer Cyber PP's
may have been improved so that doing such things is far less painful than
it was then.

Hindsight is wonderful, isn't it!

/kim


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