The MAD Computer Program | Hacker News Reader

The MAD Computer Program

meatfighter.com

72 pointspplonski8622 comments

Ah good times, I remember spending countless hours typing in source code like this. At one point I also submitted the source for a couple of games I'd written to a computer magazine when I was younger, and was delighted to get one of them published. My address was included; if people sent me a $5 note and a 5.25" floppy I'd return their disk containing a copy of the game plus a couple of other "bonus" apps I'd written. I think I sold maybe 4-5 copies this way and was pretty pleased with myself at the time!

I do recall having to send a disk back and forth a few times to one customer because I'd reformatted his disk to double-sided (360k) but he only had a single-sided drive[0]. After he tried and failed to read it, I spoke to him on the phone, figured out the problem and asked him to return it. I reformatted the disk back to single-sided (180k) so he could try again. That didn't work either since it turned out the single sided drive only supported 160k rather than 180k, which necessitated yet another round trip of his disk through the postal system.

[0] I'd been using a Sanyo MBC-555-2, he had a Sanyo MBC-550.

Do you mean double sided or double density?

I distinctly recall having to rotate discs on my BBC, and seems strange to needlessly break backwards compatibility.

His drive was single-sided double-density, giving 160k storage. The ones I was using were double-sided double-density, providing 360k of storage. I have no idea why the single sided drive had a bit less than half the storage of the double sided one though.

There were two "hacks" available with single vs double sided drives and disks. 5.25" floppies had a small notch in the side that, if you covered it with a sticker, meant the drive treated it as read-only. By cutting an equivalent notch in the opposite side of a disk to make it appear writable it was possible to flip it over 180° and use both sides of a double-sided disk in a single-sided drive. Conversely, disks that were rated as single-sided (and hence cheaper) could generally still be used successfully in a double-sided drive, though it wasn't recommended to store anything too important that way because the failure/problem rate was noticeably higher. My guess is that the single sided disks were binned as such due to them failing tests on one of the sides during manufacturing.

Ah I see, so he had sent you a single sided disc then, that makes sense.

Quick translation to javascript: https://jsbin.com/qipapokova/1/edit?js,output

(Note I flipped it with css, too lazy to fix in js :)

Edit: Perhaps more historically accurate if you can watch it draw: https://jsbin.com/veniwodidi/1/edit?js,output

> Perhaps more historically accurate if you can watch it draw

Were computers really that slow back then or is that effect exaggerated for nostalgia? Really hard to imagine computers that slow for us young generation.

If anything, my simulation is being generous, at least for the C64: https://www.youtube.com/watch?v=k4h9a2QGdQM

That is, drawing from BASIC though. Games weren't saddled with that, so they drew faster.

A comprehensive comparison would be hard, but just by straight instructions per second: An old 6502 is probably 1/2 a MIP with each instruction dealing with 8 bits. A new AMD Ryzen is 350,000 MIPS, with each instruction able to deal with 64 bits. So, 700k times faster, not including the difference between 8bit and 64bit.

Man, that video makes me appreciate my old TI-83 so much more, even with its lower resolution...

Absolutely. I remember Elite on the Acorn Electron (think lower spec Beeb), and it would render in single digit FPS, in black and white wire frame. Just lovely.

I spent an entire night typing this into my Commodore 64. And it didn't work. I also messed up the save to tape, and never had the patience to type it all over again.

Real world software programming was hard, and it still is. It remains just as frustrating when it doesn't work.

Great story! I remember typing in a few 'magazine programs' also, on my Vic-20.

The most frustrating part for me with those magazine programs was the number of them written for a computer other than mine. I drooled over all the cool C64 game programs, then went over to my section and typed in some ascii maze or text adventure.

I had a similar experience with a boxing game whose graphics rivaled anything I'd bought (or, more realistically, Fast Hack'em'd from a friend). I spent a minute or so trying to find my typo in 500 lines of random characters before giving that up as a hopelessly stupid task.

I've always wondered if I became a coder because of or in spite of that experience.

I was sad when this edition of MAD came out, because I owned a Spectravideo 318 (based on a Z80 chip) that didn't have a listing. That wasn't a surprise though - my parents must have got it super cheap thinking "it's just as good as that C64 he keeps asking for". It turns out it was "popular" in Japan, but no one I knew even owned one, let alone had any games to share!

However, I also noticed that in MAD for many months afterwards there was always at least one "letter from readers" suggesting typos and bugfixes to try and get it to work.

I remember thinking that maybe I dodged a bullet!

I think I typed this twice into my C64 and never got it working either. Always wondered what the output looked like.

every summer for about 3 years, i tried to key this into my apple IIe. Came up with all sorts of schemes to keep track of my place in the listing, but never got it to display more than a few lines of the illustration, which I declared a minor victory (the first 2 times, it didn't work at all!).

This experience ingrained my top row typing skills in a big way though...

I was in college about this time; did a lot of programming on the Apple //e. I didn't have one, but the college I attended had a lab full of them in the business department, and a lab full of boring green-screen IBMs in the computer science department. What can I say, I like color. I wrote a bunch of Apple code that is long gone and not lamented, and created some RPG materials that I did rescue from the floppys a couple of decades ago.

I typed this into a Commodore C64 with a kid next door. It felt like an eternity to type those rows.

The first time something was bad and we had to debug. The disappointment was tremendous.

The next time it worked, and felt magical how all that sweat and effort and those nonsense numbers became Alfred.

"What me worry?"

Interesting, loved MAD and had a VIC-20 early in the eighties, but think by '85 (the days of Miami Vice) I'd already put it into storage. So, while the issue looks familiar, don't think I tried it.

I have most of my MADs in a box around here somewhere.

I noticed that most of the DATA numbers were negative. I swapped the signs on all the numbers, and that saved about 250 characters. That would have added up when lots of machines still had 16KB of RAM.

I used to do these all the time, I think it was mainly from Byte magazines I would get from the library. It was on a TI-994A. External floppy drives were a godsend over the tape machine.

I remember being 8 years old, having a real copy of this magazine and typing this into my TI-99/4A. It worked. It was amazing.

This silly program undoubtably helped me get interested in technology.

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