Path: utzoo!attcan!uunet!super!rminnich
From: rminnich@super.ORG (Ronald G Minnich)
Newsgroups: comp.arch
Subject: Re: Sw vs. Hw BitBlit.
Message-ID: <602@super.ORG>
Date: 8 Aug 88 14:54:15 GMT
References: <399@ma.diab.se> <1313@ucsfcca.ucsf.edu> <61783@sun.uucp> <1315@ucsfcca.ucsf.edu> <62296@sun.uucp> <4409@cbmvax.UUCP> <1988Aug3.153415.9033@utzoo.uucp>
Sender: uucp@super.ORG
Reply-To: rminnich@metropolis.UUCP (Ronald G Minnich)
Organization: Supercomputing Research Center, Lanham, MD
Lines: 39

In article <1988Aug3.153415.9033@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
>In article <4409@cbmvax.UUCP> jesup@cbmvax.UUCP (Randell Jesup) writes:
>>	...  Pike et al were only looking at blitters used for text-
>>oriented terminals that also had graphics capabilities.
>I would conjecture -- note that this is only a conjecture -- that even
>the highly graphics-oriented machines spend far more time displaying plain
>old text than most people think.  I'd love to see numbers on this; does
>anybody have some?
   well i would guess mine does, when i am not playing computer games :-)
(about 50% of the time?) 
   One issue that has been ignored in this discussion is that we are 
all talking about slightly different things. Henry is talking about blitters,
and others are talking about amigas. Seems to me that there is a BIG
difference between the graphics supported by Blit and the graphics 
supported by the amiga- something that many probably don't know.
For example, the amiga supports hardware windows. Now, they are
a little limited, in that they have to be the width of the screen, so
as a result the amiga OS people implemented them as screens, with multiple
of the traditional type of window per screen. Thus you actually have
several different worlds, each with their own color map and such, each 
with their own set of windows. You can have a game with 10 open windows
on one screen, then flip to your X-windows screen with its 5 or 10 windows
and its 2-bit-plane color map, then to your Deluxe Paint screen with
its own 4096-color HAM map. The Screens are one thing i like best about
the amiga, esp. since they can overlay each other on the physical display
and flipping between them takes no time at all. I have yet to see 
this sort of graphics on anything other than an amiga, and i miss it 
a lot when i use other machines.
   It was mentioned somewhere at one point that the original Xerox
workstations wanted to support this sort of multiple world environment, 
but the graphics support was not there (I think it was the Dorado).
   The other day i saw an IBM Peanut running X windows. The color map
on the VGA changed as you moved from window to window. It just about
drove me bats. That machine really needed screens, but i think its
gotta happen in hardware if it is going to happen at all.
    To sum up,
   Amiga graphics hardware != blitter chip.
		and maybe  >
ron