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From: garry@TCGOULD.TN.CORNELL.EDU.UUCP
Newsgroups: mod.computers.workstations
Subject: Re: X and GKS
Message-ID: <8612100143.AA11696@tcgould.tn.cornell.edu>
Date: Tue, 9-Dec-86 20:43:26 EST
Article-I.D.: tcgould.8612100143.AA11696
Posted: Tue Dec  9 20:43:26 1986
Date-Received: Wed, 10-Dec-86 00:16:20 EST
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: garry%cadif-oak@cu-arpa.cs.cornell.edu
Organization: Cornell Engineering && Flying Moose Graphics
Lines: 36
Approved: works@red.rutgers.edu

In a recent article larry@JPL-VLSI.ARPA wrote:
>How does X relate to the ANSI and soon-to-be ISO Graphical Kernel
>Standard?  Do they serve the same or similar purposes?  If so, why
>this needless duplication?  Or is there some good reason for it?

X is a "windowing system" while GKS is a "graphics package".
Technically, the distinction is mostly a matter of emphasis - a
graphics package will as a rule go on at great lengths about
geometry, renditions, and transformations, and only touch moderately
upon text and screen windows, A windowing system, on the other hand,
will concentrate on doing text and updates speedily, and keeping the
screen windows organized, and only touch upon geometry and
transformations.

Graphics packages generally allow some form of "stored display list"
- but do not allow sharing of the screen - while windowing systems
generally allow (encourage) multiprocessing on a single screen but
run in "immediate mode". Both kinds of system are can be either
programmed or utility-driven.  As a rule of thumb, if you have both,
you'll use standard utilities to drive the windowing system (one of
the commonest window system utilities is the terminal emulator) and
you'll write programs to drive the graphics system.

None of the above distinctions are absolute - both kinds of system
have the same purpose of displaying information to a user on a
graphics screen.  They just differ in particulars between what's made
easy to do and what's made hard/impossible.

There are numerous books in the bookstore on GKS and other graphics
packages; I'm not aware of any books on X yet, but for a related
windowing system you might try the "Smalltalk 80" book.

Hope this helps. Software, at this level, is *not* simple. Rumors to
the contrary are unfounded. :-)

garry wiegand   (garry%cadif-oak@cu-arpa.cs.cornell.edu)