rnelson@eecs.wsu.edu (Roger Nelson - Grad Student) (03/10/91)
In article <3XX9VY1@xds13.ferranti.com> peter@ficc.ferranti.com (Peter da Silva) writes: >Some televideo-braindamage style terminals allow you to set the attribute >character width to 0, allowing you to write a character in the magic cookie >cell. So the magic cookies don't show up on the screen but still do weird >stuff like set the rest of the screen to the attribute. 1. Why did terminal manufactures go with magic cookies? The magic cookies make display attributes useless. 2. In working with TVI910, TVI912c, and HP700/41 terminals, I've tried playing around with the terminfo (HP/UX) magic cookie glitch settings and haven't been able to work around the problem. I haven't been able to get rid of the magic cookies when using Esc codes in local mode either. The picture on the TVI manuals show a nice data entry screen using all the display attributes, but I see no possible way to make that data entry screen, how did they do it?
seanf@sco.COM (Sean Eric Fagan) (03/10/91)
In article <1991Mar09.215153.27776@eecs.wsu.edu> rnelson@yoda.UUCP (Roger Nelson) writes: >1. Why did terminal manufactures go with magic cookies? The magic cookies > make display attributes useless. Because memory was expensive, and saving memory by making the attributes take up a screen position helped the situation. (They got one byte per character on the screen; the most common method, nowadays, is to have each character on the screen take up two bytes: one for the character, one for the display attributes.) -- -----------------+ Sean Eric Fagan | "*Never* knock on Death's door: ring the bell and sef@sco.COM | run away! Death hates that!" uunet!sco!sef | -- Dr. Mike Stratford (Matt Frewer, "Doctor, Doctor") (408) 458-1422 | Any opinions expressed are my own, not my employers'.
gwyn@smoke.brl.mil (Doug Gwyn) (03/11/91)
In article <1991Mar09.215153.27776@eecs.wsu.edu> rnelson@yoda.UUCP (Roger Nelson) writes: >1. Why did terminal manufactures go with magic cookies? Cheaper hardware implementation (less RAM required). They could get away with this when selling to contracts that called for certain video attributes but did not further constrain them to be provided on a per-character basis without loss of displayable characters. If you're writing terminal specs, watch out for this.
kew@cims.com (Keith Walker) (03/11/91)
rnelson@eecs.wsu.edu (Roger Nelson - Grad Student) writes: >1. Why did terminal manufactures go with magic cookies? The magic cookies > make display attributes useless. Magic cookies were used so that each character on the screen mapped to a position in memory. This made the video driver code more simple, which was important in those days prior to cheap microprocessors, and cut down on memory requirements, which was also important back then as memory was quite expensive. We have magic cookies now for the same reason we have 80486's supporting 8088 code: Inertia. Most late-model Televideo terminals support the old style magic-cookies as well as character oriented attributes. >2. In working with TVI910, TVI912c, and HP700/41 terminals, I've tried > playing around with the terminfo (HP/UX) magic cookie glitch settings and > haven't been able to work around the problem. > I haven't been able to get rid of the magic cookies when using Esc > codes in local mode either. The picture on the TVI manuals show a nice > data entry screen using all the display attributes, but I see no > possible way to make that data entry screen, how did they do it? You'll not get rid of the magic cookies that easily. If you could it would have been done. If you've got tvi910's and 925's around, you're doomed to working with them :-( -- Keith Walker Domain: kew@cims.com UUCP: uunet!proto!cims2!kew Voice: +1 509/466-9384
allbery@NCoast.ORG (Brandon S. Allbery KB8JRR) (03/15/91)
As quoted from <9103100202.aa16074@xenitec.on.ca> by : +--------------- | In article <1991Mar09.215153.27776@eecs.wsu.edu> rnelson@yoda.UUCP (Roger Nelson) writes: | >1. Why did terminal manufactures go with magic cookies? The magic cookies | > make display attributes useless. | | Because memory was expensive, and saving memory by making the attributes | take up a screen position helped the situation. (They got one byte per +--------------- That, and the fact that Televideo licensed their terminal emulation ROMs to just about anyone for relatively cheap. Why invent another VT100 emulation when you could buy Televideo's inexpensively and get a product out the door cheaper and faster? Alas, in these days of programs that want screen attributes to play with, it's become a problem. We have customers who don't understand why we won't sell them Wyse 50s to use with MS Word... until we show them the two possible lossages. (1: program fails to start with an error message about magic cookies. 2: use the protect attribute... no on-screen underline, bold, etc.) ++Brandon -- Me: Brandon S. Allbery Ham: KB8JRR on 40m, 10m when time Internet: allbery@NCoast.ORG permits; also 2m, 220, 440, 1200 America OnLine: KB8JRR // Delphi: ALLBERY AMPR: kb8jrr.AmPR.ORG [44.70.4.88] uunet!usenet.ins.cwru.edu!ncoast!allbery KB8JRR @ WA8BXN.OH
guy@auspex.auspex.com (Guy Harris) (03/17/91)
>Why invent another VT100 emulation when you could buy Televideo's >inexpensively and get a product out the door cheaper and faster? I assume "Televideo's" doesn't refer to any VT100 emulation by Televideo, but to an emulation of a non-VT100-compatible Televideo terminal, 'cuz VT100s, bless their heart, don't have magic cookies....