Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site eneevax.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!umcp-cs!eneevax!hsu From: hsu@eneevax.UUCP (David T. Hsu) Newsgroups: net.micro.atari Subject: Re: In defense of J. Demar (excessively long) Message-ID: <384@eneevax.UUCP> Date: Sat, 12-Oct-85 23:29:30 EDT Article-I.D.: eneevax.384 Posted: Sat Oct 12 23:29:30 1985 Date-Received: Tue, 15-Oct-85 05:35:48 EDT References: <869@cvl.UUCP> Reply-To: hsu@eneevax.UUCP (David T. Hsu) Distribution: net Organization: U of Maryland, EE Dept., College Park, MD Lines: 77 Well, there was an Amiga at our (somewhat sucessful) computerfest today, sponsored by the University Personal Computing Assoc. (of which I am an officer) as well as 5 or 6 ST's and a lot of demos, so I'd like to expand on some of this discussion. GG: ...Unless the ST has some sort of dual-ported RAM, the screen data must come from the same data bus in the ST as well. JD: ..First, there are a pair of chips working together to optimize data bus and screen data access. The memory controller prefetches 16-bit data directly for the 68000 and also places screen data onto a separate bus for the screen refresh chip. This operation only steals 8-18% of the available true CPU time. GG: If you measure a computer's worth by the number of chips, you might as well pick an IBM over a Mac. Perhaps the custom chips in the AMIGA are better integrated to perform several functions in one chip. Thus you do not need MORE chips if three can do the job. GF: non sequatur (sp?) myself: Regardless of the memory arrangement, I found the ST's graphics to appear intrinsically clearer. Perhaps Atari uses a better monitor, or maybe they tighten up the dot edges, but the amiga's graphics had a fuzzier, blurrier, yet warmer appearance. For data, I would have gone with the Atari's no-nonsense display, but the Amiga DOES do an impressive job on pre-drawn graphics, and the color text display is less objectionable than Atari's. As for the chips, well, maybe the IBM DOES have more chips than a Mac, or than the //e, but remember...all those PALs and semicustom gate arrays DO replace lots of so-called-glue. Remember how Apple's MMU and IOU replace some 140-odd chips? And since when did manufacturers stop bragging about how many gates and transistors they've packed into the latest design? JD: The windows are poorly configured and move with flicker. GG: They do? Not in my AMIGA. GF: Maybe they do in his AMIGA. myself: They sure didn't in the Amiga at the 'fest. In fact, I was very impressed (in terms of graphics power) when, while running the 'robo-city' demo (two characters and a dog walk across the screen behind an animated hydrant) the person at the Amiga 'grabbed' the entire page and slid it off the bottom of the screen while the demo was running. No flicker. No redrawing. In fact, the demo kept running at the same pace while we ran its window all over the place. Very nice, but there was severe flicker on horizontal white lines in 640x400 mode, and while not apparent in solid areas, a violent flicker appeared in heavily colored/dithered spots on some screen captured shots. No, I don't mean slightly grey edges. The dots literally shook. caveats...the salesman tried to explain that the system unit had 512k in it, but he included the ram in the kickstart. Unlike the Atari, when you get your system roms, you'll find yourself back to 256k. Because they won't build the extra in after it's served its usefulness. Also, the much-ballyhooed bouncing ball demo, although fun to look at, was not that impressive. The 'thud' sound probably contributed to 60% of the effect, simply because it sounded massive. But the shadow and ball both moved on the same path, at fixed velocity, and the only surface animation was a set of checkerboard bands rotating constantly on the ball. Reminded me of a Mindset without flicker. The Atari booth, on the other hand, showed some simpler, safer graphics, but then again, what do you use real-time graphics for? I found the Atari to be adequate (and very cheap). overrunning my expected line-limit, -dave -- ------------------------------------------------------------------------------- David Hsu hsu @ eneevax.umd.edu Communications & Signal Processing Laboratory hsu @ sphinx.ee.umd.edu Department of Electrical Engineering hsu @ mit-prep.arpa University of Maryland hsu @ umd2.arpa "You see? You SEE???"