Path: utzoo!news-server.csri.toronto.edu!rutgers!usc!samsung!olivea!oliveb!isc-br!tau-ceti!cims2!kew
From: kew@cims.com (Keith Walker)
Newsgroups: comp.terminals
Subject: Re: Why magic cookies? (was: Alternate character modes...)
Message-ID: <1991Mar11.003842.5807@cims.com>
Date: 11 Mar 91 00:38:42 GMT
References: <1991Mar09.215153.27776@eecs.wsu.edu>
Organization: CIMS, Inc.
Lines: 31

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
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