Re: apples vs oranges (was Re: computer video (was Re: Free IBM AT))

From: Ray Arachelian <ray_at_email.domain.hidden>
Date: Thu, 09 Mar 2006 12:08:13 -0500

Eh? Somehow I think you're being a troll.

I'm not sure how converting a modern MPG, which was not available back in 1982, into a bunch of 80x25 or 40x25 color attributes and requiring a sound blaster card, which did not exist at the time of the introduction of the PC somehow proves that one system is better than another. Especially since it was never meant to, or actually used in this way.

Yes, it's very cool, but, um, so what? Each system has its own technical merits, and it's own market, and each had both their own successes and failures.

What I mean by 2K or 4K of bandwidth is this. The stuff you see on that display is not in hires or even lowres graphics. In fact, it is just tweaking of the color attributes, which are, as expected 80x25. 80*25=2000 bytes. aka 2K. Now that display actually had 4K of memory in that mode. 2K was used for color information, broken up into nibbles, that is 4 bits for the foreground color, and 4 bits for the background color.

Even that's a rather generous assumption. You could go into 40x25 mode, and write only to the background color, so in that case you're writing to 1000 bytes, of which you only use half a byte for the 16 color background - so effectively it would by 500 bytes, though you really do have to write to all 1000 in 40x25 or all 2000 in 80x25. This is what I mean about it being the size of two icons. You're getting excited over a movie displayed in less screen real estate than an icon on a modern display.

So, yes, the total bandwidth to display a movie in this way on an IBM PC is well within it's capability, and while impressive on the surface, it's still within the limits of an 8 bit 4.77MHz 8088.

Indeed, I do have to wonder what decade we're comparing here. MPG video did not exist in 1982, and yes, when I say 720x364x2, I am talking about the Lisa and not the Mac. Incase you've not noticed, this forum is called "Lisa List." Not "The Original Mac 128 List." That 720x364x2 took up 32K of RAM vs at most 2K on the PC. Big difference in bandwidth there. It's certainly not possible to capture that video on a PC of that era and pre-process it into the format needed to display it back. So to play back a movie on a Lisa, you'd need to push 32KBytes 30 times a second. To play back this demo, you need to push 2Kbytes 30 times a second - a lot easier to do.

While I could get either an IBM PC 5150 with a CGA card, and color monitor, or a Mac 128 for the $2.5K you mention, these are two different products, in two different markets that have very little to do with each other, other than both being personal computers from the 1980's. The PC was what, 1982, the Mac was 1984. The Lisa, which is what this forum's topic is about, is far closer to a mini-computer, and was actually built by folks who previously worked on mini's. I'd say it was a workstation, though that word wasn't used at the time.

I'm sure that if you were to challenge someone from the demo scene, you'll find they could come up with a dazzling demo that would run on a stock Lisa 2 and be as impressive, if not more so. Ditto for the original Mac 128 - oh wait, it was already done, and it talked too as Larry Rosenstein already pointed out here: <>

Which system is better? Depends on what you want to do and for how much. Should the PC have had a display controller based on character generation and attributes? What about the Apple II, the Commodores, et al? Sure. Should the Lisa and the Mac? Hell no - it was designed on purpose to always use bit mapped graphics in order to produce paper documents. Different markets, different price points, different technologies, different reasons for their own designs. That would be comparing apples, eh, to um, oranges.

Each system has both their good and bad points, each has their technical merits, and each has their niche. They are all as wonderful as you can find reasons to use them. An icon sized movie does not make one overall system better or worse, nor does it say that all systems should use character generator based controllers.

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Received on 2006-03-09 09:19:45

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