David Horne's 1K Chess on the ZX81 (2001) • Hacker News Board

Re: David Horne's 1K Chess on the ZX81 (2001)

#61

Post by sago » Thu, Mar 05, 2015, 8:05 PM UTC

T-hawk wrote: post #55

VonGuard wrote: post #20

Just for the record, the Atari 2600 also had a chess game with AI. It also had only 1024 bits of RAM, but it had access to all of it because there was no OS or underlying hardware support, like in the Speccy. So while this is definitely amazing, the 2600 version is very close in the "insanely well coded" category, especially because the 2600 had some SERIOUSLY quirky hardware to deal with. For example, on the 2600, y…

Not exactly; this overstates the complexity of the chessboard display. The order isn't exactly what you wrote, it's bits 4567 / 76543210 / 01234567 for the three playfield registers for the left half of the screen. This can be either repeated or mirrored for the right half. A common trick as 2600 Video Chess did was to simply not use the leftmost (mirrored to rightmost) register, which still gets you 16x2 bits of mir…

This reply is exactly what I love about HN. I'd like to buy you a drink and talk of vintage hardware :)

Re: David Horne's 1K Chess on the ZX81 (2001)

#62

Post by jameshart » Thu, Mar 05, 2015, 8:07 PM UTC

ctdonath wrote: post #4

StavrosK wrote: post #2

Why does the author say "memory" when he means "disk space"? Or does he actually mean "memory", as in "RAM"? In that case, why would the size of the executable matter?

There was no "disk" on a ZX81. Storage was audio cassette tape. The size of the executable mattered because it all had to fit in 1024 bytes RAM (no "K", no "M", certainly no "G") with all video & operating system memory.

"Operating System" is a stretch. BIOS would even be an overelaborate term for what the ZX81 had, given that IO was basically handled through fixed memory-mapping. What it had was a few inbuilt ROM routines and a main run loop that cobbled together a text-mode display, a line editor and a basic interpreter.

Re: David Horne's 1K Chess on the ZX81 (2001)

#63

Post by mgkimsal » Thu, Mar 05, 2015, 8:12 PM UTC

ymra wrote: post #23

VonGuard wrote: post #20

Just for the record, the Atari 2600 also had a chess game with AI. It also had only 1024 bits of RAM, but it had access to all of it because there was no OS or underlying hardware support, like in the Speccy. So while this is definitely amazing, the 2600 version is very close in the "insanely well coded" category, especially because the 2600 had some SERIOUSLY quirky hardware to deal with. For example, on the 2600, y…

It may only have had 128 Bytes of RAM, but it used 4K ROM cartridges, even more than that if the cartridge used bank switching. So Atari 2600 programmes had quite a bit more room to fit inside.

IIRC, early cartridges only had 1 or 2k - the 4k was a limit for a while, but I don't think they all shipped with 4k in the beginning (cost savings). IIRC there was a trick later to allow for 8k cartridges (Pitfall II was 8k, I think, but memory may be failing me).

Re: David Horne's 1K Chess on the ZX81 (2001)

#64

Post by SonicSoul » Thu, Mar 05, 2015, 8:17 PM UTC

sago wrote: post #59

j2kun wrote: post #47

I'm not sure why the size of a program has any serious bearing on it's greatness. Sure it's an incredible feat of engineering, but shouldn't the "greatest program ever written" be primarily judged by what it allows us to do, not need to do, to build, or what insights it provides? For example, certainly the first widely used assembler was a "greater" program than any chess game, not only because it stopped us from hav…

The 4 minute mile was amazing because of the four minutes, not because someone managed to run a mile. Amazing feats in the face of incredible constraints are inherently worthy, I'd say.

A better analogy would be 'greatest movie ever made' was so because it was done on a budget of $1000.

Better analogy in context of this thread that is

Re: David Horne's 1K Chess on the ZX81 (2001)

#65

Post by oldmanjay » Thu, Mar 05, 2015, 8:21 PM UTC

metaphorm wrote: post #51

TheOtherHobbes wrote: post #50

Earlier quoted context omitted.

Not true. A lot of people were so amazed by the potential of ZX81 game programming they became programmers themselves - sometimes games programmers, but just as often general developers. If the ZX81 hadn't done anything of interest it wouldn't have persuaded those people that awesome programming was possible. Dismissing this kind of coding as a side show is arrogant and ill-informed. The ZX81 itself was a similar pro…

please don't put words into my mouth or deliberately misinterpret me for your own purposes. this kind of rhetorical dishonesty really reflects badly on you. I didn't dismiss it as a sideshow. My exact words were "low importance side project". It was a side project, as in, not the code he was working on full time for his business. It was low importance, because it was just a chess game, not a piece of system software…

I don't like the way you said this, but I agree with your point. People bring way too many personal biases to public discourse.

Re: David Horne's 1K Chess on the ZX81 (2001)

#66

Post by sago » Thu, Mar 05, 2015, 8:27 PM UTC

nsxwolf wrote: post #22

ColinWright wrote: post #13

Earlier quoted context omitted.

I didn't downvote you, but you asked a question the answer to which is easily available with the most trivial of web searches. You assumed he meant "disk space", assuming the author made a mistake when you could easily have checked and not asked the question here. In some sense, it's not a legitimate question for this context.

Must we obtain all information via dry web searches, and never from human exchange?

Well, this is the site where, in an article about "the 36 questions it takes to fall in love" someone suggested building a bot so you could go through the questions on your own.

Re: David Horne's 1K Chess on the ZX81 (2001)

#67

Post by sago » Thu, Mar 05, 2015, 8:32 PM UTC

SonicSoul wrote: post #64

sago wrote: post #59

Earlier quoted context omitted.

The 4 minute mile was amazing because of the four minutes, not because someone managed to run a mile. Amazing feats in the face of incredible constraints are inherently worthy, I'd say.

A better analogy would be 'greatest movie ever made' was so because it was done on a budget of $1000. Better analogy in context of this thread that is

Why? Seems like a much poorer analogy to me, since it is trivial to make a movie for much less than that. It falls into the same trap as the commenter above, the 'greatness' is due to the quality of the program, rather than just making it exist at all.

Re: David Horne's 1K Chess on the ZX81 (2001)

#68

Post by wazoox » Thu, Mar 05, 2015, 8:38 PM UTC

mgkimsal wrote: post #63

ymra wrote: post #23

Earlier quoted context omitted.

It may only have had 128 Bytes of RAM, but it used 4K ROM cartridges, even more than that if the cartridge used bank switching. So Atari 2600 programmes had quite a bit more room to fit inside.

IIRC, early cartridges only had 1 or 2k - the 4k was a limit for a while, but I don't think they all shipped with 4k in the beginning (cost savings). IIRC there was a trick later to allow for 8k cartridges (Pitfall II was 8k, I think, but memory may be failing me).

IIRC, Pitfall II was 2K. 255 different levels in 2K, memorable isn't it ? :)

Re: David Horne's 1K Chess on the ZX81 (2001)

#69

Post by Someone » Thu, Mar 05, 2015, 8:39 PM UTC

tzs wrote: post #37

Impressive, as is the recent smaller program from a French programmer. Note, however, that both have sacrificed some rules. I believe they have both left out en passant, which is rare enough that it won't be missed most of the time. It's rare enough that if you use it against a casual player, there is a good chance they will accuse you of making it up. Castling, however, which is also omitted, is much more serious. G…

"That raises the question of what is the smallest implementation of full chess?"

Technically, that is a program that prints "I concede". If you also want it to play black (IIRC, this 1k chess doesn't) and validate moves, it would have to know the 20 opening moves for white and concede on black's first move.

Of course, you could claim that isn't playing chess. But it is hard to define what, then, is chess. Picking a random move? Moving only one of one's knights, and conceding when it is taken? Does a program need an ELO rating of at least 1500 to be considered an implementation of 'full chess'?

Re: David Horne's 1K Chess on the ZX81 (2001)

#70

Post by sago » Thu, Mar 05, 2015, 8:39 PM UTC

tzs wrote: post #37

Impressive, as is the recent smaller program from a French programmer. Note, however, that both have sacrificed some rules. I believe they have both left out en passant, which is rare enough that it won't be missed most of the time. It's rare enough that if you use it against a casual player, there is a good chance they will accuse you of making it up. Castling, however, which is also omitted, is much more serious. G…

There's a rather ahistoric perspective at work here. I wonder if there's a generational thing.

ZX81 chess was so impressive because it was impossible (at least, I'd have bet real money on it). It was the thing programmers namechecked as the kind of thing you couldn't do on these newfangled cheap home computers. You need a 'real' computer to do it. There's just no way. I was writing programs for the ZX81, and the kind of simplicity they had to have is difficult to communicate to someone who grew up with 8086 PCs on their desks. Get an emulator and have a go.

So, you're right, it wasn't 100% total, complete, full chess. But, good god, it was chess, recognizably chess, playably chess! And the guy did it on a freakin' ZX81. It is difficult to explain how astounding that was.

Pointing out it's lack of castling and en-passant (and stalemate, repetition, etc) seems a bit churlish then.

That's why the challenge for the smallest chess program uses the ZX81 rules, not the full rules. It is why smaller programs make it to HN, whereas you don't know about the smallest program to play FIDE chess. It is a historical honoring of that great achievement.