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Comment by fit2rule | Hacker News Reader

Having grown up with this whole "step backwards" that we took when the PC hit the scene, the most interesting aspect of this demo has been the understanding that some people just don't get why it is so freakin' AMAZING that they were able to coax such art out of this severely limited hardware. CGA was never supposed to be able to produce such complex and beautiful images - take a look at the screenshots here:

https://www.google.at/search?q=cga+graphics&tbm=isch

.. and what do you see? Mostly Cyan/Magenta graphics, which was 'the norm' for that era. It took another few years before we got EGA - and then, finally VGA - graphics, which we've all become very accustomed to in this day and age.

But seeing 16 - and then 256 colors - being produced by a CGA is truly a feat of technical wonder. For anyone who doesn't get why this demo is so important, you have to understand: we never, ever thought such capabilities were possible with CGA hardware.

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I tried reading the technical expectation, a lot of it was lost on me, but it seems like they just implemented bug fixes and tweaks but added nothing that wasn't impossible in ~1981? Was this possible back then even?

Only when using composite output, I think. The 9-pin connectors had TTL-level pins.

Actually, IBM did not supply a TTL-monitor for CGA until 1983 (the 5153). So in the early days, using the composite output (which is standard on IBM CGA cards) would be the easiest way to get CGA output to a screen in 1981.

I stand corrected. :) Did those cards have an RCA connector? I came across a 64K full-width EGA card that had two of those, but never figured out what sort of output they produced.

They did, and it worked! The RCA connectors on the IBM EGA card aren't connected to anything - they only work if an add-on daughterboard is installed (I don't know if that daughterboard was ever actually made).

Yes, CGA has an RCA connector on the back for NTSC composite. This is what we used for the demo. There is also a header on the card itself, to which an RF modulator can be connected, for a regular TV antenna input (this was an option, probably because of regulations. An RF modulator generates a lot of interference, so fitting one stock would require expensive shielding. Fitting it 'aftermarket' circumvents that). The IBM 5155 portable PC abuses this header to connect the composite signal to an internal monochrome CGA monitor.

That is correct. All you need is an IBM 5150 with an IBM CGA card and 640KB of memory. The 640KB of memory may have been a very expensive option in 1981, but not impossible. Most parts of the demo don't need nearly that much memory anyway, and would probably run with 256KB or less.

The 'impossibilities' are mainly on the software side: we require DOS 2.x, which didn't exist yet in 1981 (although it will run on a 1981 machine). You would also need DOS 2.x to support the 360KB double-sided 5.25" floppies. They existed in 1981, but early DOS only supported 120KB per side, and early PCs were fitted with single-sided floppy drives.

But this could all be worked around (and some parts could be modified to require less memory as well), so all of the audiovisual effects you see in 8088 MPH are possible on an actual stock 1981 machine, with DOS 1.0 and a single-sided 5.25" floppy drive.

Yes, if 8088 MPH was sent back in time to 1981 it would have been possible to run it on even the very first PCs. You'd need a pretty expensive RAM upgrade (640kB was a lot then - the first PCs had up to 64kB on the motherboard) a double-sided floppy drive (or flip the disk at the right point in the demo) and a time-travelled copy of DOS 2.0 or later.

Making it in 1981 would have been a lot more difficult - we cross-compiled (or cross-assembled) most of it on modern hardware and the graphics conversions would have been very slow without a modern PC. Not to mention the modern tools used for composing the music and drawing the art, or how much we used the internet for research, or how we built on many years of demoscene research. But there's no theoretical reason why it couldn't have been done then.

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