Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!lll-crg!styx!ames!amdahl!kim From: kim@amdahl.UUCP (Kim DeVaughn) Newsgroups: comp.unix.wizards Subject: Re: Re: CYBER word length Message-ID: <4177@amdahl.UUCP> Date: Thu, 13-Nov-86 20:28:52 EST Article-I.D.: amdahl.4177 Posted: Thu Nov 13 20:28:52 1986 Date-Received: Thu, 13-Nov-86 23:46:55 EST References: <4169@amdahl.UUCP> <254@bsdpkh.UUCP> Organization: Amdahl Corporation, Sunnyvale, CA 94086 Lines: 47 In article <254@bsdpkh.UUCP>, latham@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 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 -- UUCP: {sun,decwrl,hplabs,pyramid,ihnp4,seismo,oliveb}!amdahl!kim DDD: 408-746-8462 USPS: Amdahl Corp. M/S 249, 1250 E. Arques Av, Sunnyvale, CA 94086 CIS: 76535,25 [ Any thoughts or opinions which may or may not have been expressed ] [ herein are my own. They are not necessarily those of my employer. ]