That's the kind of thing I come here for! Tiny hacks of all sorts.

Same. I come here to witness what is basically programming magic to me. I'll need a couple of life times before I can become this skilled.

You can do “magic” with relatively easy things. For example, spend a weekend with https://forthsalon.appspot.com or processing.org and see where you can get to...

I was confused as to how you could represent a bootable CD image in printable characters. It turns out that you can't. This is a tweet of a perl script which creates a cd.iso file that you can then boot from. The perl script significantly decompresses the data in the tweet.

That said, this is a playable game in around 60 bytes of actual data which is impressive.

I'm reminded of the RSA in Perl "weapon" t-shirt :)

https://upload.wikimedia.org/wikipedia/commons/9/96/Munition...

Man that shirt is awesome... But man I would never wear that shirt as that looks like the crown jewel of any neckbeards collection

It's pretty light compression from what I can tell - basically just squashing down runs of nulls to a single count.

The compression is basic run-length encoding, leveraging the Perl repetition operator (x), and the property of the Perl print/say functions that they concat items passed in a list before writing to STDOUT.

https://en.wikipedia.org/wiki/Run-length_encoding

https://perldoc.perl.org/perlop.html#Multiplicative-Operator...

https://perldoc.perl.org/functions/say.html

https://perldoc.perl.org/functions/print.html

I remember x86 real mode back in the day. Pretty hideous and hacky compared to what we have now.

What's real mode?

what we have now

x86 processors still boot into real mode…

It's my understanding that UEFI actually comes up directly into long mode?

"UEFI firmware performs those same steps, but also prepares a protected mode environment with flat segmentation and for x86-64 CPUs, a long mode environment with identity-mapped paging. The A20 gate is enabled as well."

- https://wiki.osdev.org/UEFI

Your snake game doesn't even have food for the snake to eat? The snake just grows without eating, until the head collides with the tail somewhere? Pssh, amateur hour...

/s (Just kidding this is actually super cool.)

It's Tron-ish (the post says Tron, where did you read snake?) :P

It's a fair assumption to make, as the difference between Tron and Snake is effectively just single player vs multiplayer.

No it isn't. In TRON you leave a trail behind. In Snake, you grow as you eat and drag your body along the path you crawled. TRON's trail is static, Snakes body is dynamic.

I said effectively.

TRON's trail is static, Snakes body is dynamic.

And that difference only exists to support the single player vs multiplayer dynamic. If Snake left a Tron tail then it would be a very short, unfun experience. If Tron didn't leave a permanent trail then matches would last too long.

And that difference only exists to support the single player vs multiplayer dynamic

Maybe the single player vs multiplayer difference only exists to support the different tail mechanics.

My first thought was to make random sectors of the first hard drive the "food"... For better or for worse, this stuff really brings me back to my teens. Nice job!

If you want to see demos (as in demoscene) in a tweet of 140 characters - https://www.dwitter.net/

This is great, and ironically it’s sitting next to another HN article where, in the comments, someone is actually defending a NYT news article that weighs in at 6MB.

In a time when most software is filled with superfluous waste and endless layers of abstraction and libraries, it’s nice to see that the art of writing minimal software is not completely lost.

Further irony: this page weighs over 30MBs, thanks to a huge GIF that is arguably not necessary for the article.

Yeah, not happy about that idiocy (probably 1MB as video) burning through 10% of my monthly bandwidth on the first day of the month...

Wow, how low is your monthly download cap?? What ISP and where?

You just made me think of a GIF-to-mp4 conversion service that runs as a proxy.

Sadly, because of the "HTTPS everywhere!!!11" thing, such a service would not be viable (it would need to rewrite the <img> to a <video> in order to work, of course).

Very cool. My version of base64 wants -d, not -D, though.

Linux vs BSD (ie Mac OS X). Sorry about that. Also, you shouldn’t paste weird looking things from the internet in your console :P

yeah paste it into your plain text editor first and then do a code review and then save it to a jump drive and spin up the old backup computer that’s been wiped clean and then open up a sandboxed vm and then remove the wifi chip and then run it

Hats off for making use of the AAA instruction. That's a very clever sequence converting up/down/left/right to -320/+320/-1/+1.

Make sure you check out the floppy version from ~3 years ago. Fits in “old” tweets (ie 140 chars): https://www.quaxio.com/bootloader_retro_game_tweet/

Man I love these things. Back before Twitter upped their character limits, I remember a trick to cram more data in a tweet was to abuse how Twitter counts characters (it attempts to count visually rather than by byte), so by using a ton of multipart emojis or larger Unicode characters to over double the information that could fit in a tweet.

I thought about using Unicode, but it felt like cheating.

Perhaps someone can fit two games in a single multibyte tweet?

This is the second time this week I've seen someone note that ISO standards are expensive - are they copyrighted or something? Why doesn't someone just publish them online for free?

Looks like the turbo button needs to be in the on position for this one: 0.05 FPS in a qemu KVM on my old P8600... I presume the game loop uses the hardware clock :P

btw my base64 util needed lower case -d

There’s a comment on the page.

For some reason, emulators (at least the ones I tried) wait 4x what real machines wait when you use BIOS int 15b 86h. You can tweak the code if you want to play at a faster speed.

There’s probably a sound explanation for this discrepancy...

I can't say I entirely understand how the Elapsed Time Wait works, but testing in qemu, I was able to get it to a good speed by replacing the

  inc cl

with a

  nop
  inc dx

By opening in a hex editor, finding

  bf86 fec1

and replacing with

  bf86 9042

If you're on a very slow system, maybe just use 2 nops or a 2-byte nop.

This reminds me a bit of the science of nanoinformatics as described in one of the Expanse novellas (The Vital Abyss):

"A thought experiment from my first course in the program: Take a bar of metal and put a single notch in it. The two lengths thus defined have a relationship that can be expressed as the ratio between them. In theory, therefore, any rational number can be expressed with a single mark on a bar of metal. Using a simple alphabetic code, a mark that calculated to a ratio of.12152205 could be read as 12-15-22-05, or “l-o-v-e.” The complete plays of Shakespeare could be written in a single mark, if it were possible to measure accurately enough. Or the machine language expression of the most advanced expert systems, though by then the notch might be small enough that Planck’s constant got in the way. How massive amounts of information could be expressed in and retrieved from infinitesimal objects was the driving concern of my college years."

Pure fiction at this point, but it would be an interesting experiment to encode data into objects that could be expressed using the mathematical ratio of their shapes or sizes.

Check out Arithmetic Coding: https://en.m.wikipedia.org/wiki/Arithmetic_coding

Yep, not fiction at all, pretty much what is used for state-of-the-art compression.

The fiction part is being able to notch the bar sufficiently precise to store any significant amount of data.

The same has been said about Pi (3.14). If you can compute, store and search enough the digits of Pi, you can reference anything by just providing the 'start' and 'finish' locations. Unfortunately, with enough digits of Pi, the 'start' and 'finish' numbers can get quite long themselves.

Years ago I tried this and basically ended up proving that if Pi is random and you are "compressing" random data, on average the start and finish numbers together are at least as long as the numbers you are trying to "compress."

Did you proove it formally or only by experiment. If it were a real proof, did you publish it somewhere?

In fact, any lossless compression algorithm has the property that the output is (on average) at least as long as the input. The best you can hope for is an algorithm that compresses the kind of data that humans want to store, at the expense of making other data a bit longer. If you're trying to compress random data then you just can't do it.

Here's a proof: consider the strings of length n or less, suppose there are M of them in total. Their average length is just the sum of all their lengths divided by M, and the average length of their compressed versions is just the total length of the compressed versions divided by M. Since the compression is lossless the compressed strings must all be different.

Since there are M strings, if any of them mapped to a string of length more than n then there must be some string of length at most n not being mapped to, so the average length can be improved by instead mapping that string to the shorter string. So any optimal compression method must map only to the strings of length at most n.

So the M outputs are just the M inputs, possibly permuted. So their total length is the same, and hence their average length is the same.

any lossless compression algorithm has the property that the output is (on average) at least as long as the input.

The article you’ve linked says nothing about average. It says that for every algorithm there’s at least some input files that increase the size. It even explains more about that:

Any lossless compression algorithm that makes some files shorter must necessarily make some files longer, but it is not necessary that those files become very much longer. Most practical compression algorithms provide an "escape" facility that can turn off the normal coding for files that would become longer by being encoded. In theory, only a single additional bit is required to tell the decoder that the normal coding has been turned off for the entire input

In fact, any lossless compression algorithm has the property that the output is (on average) at least as long as the input

I don't think this is true. If it was, lossless compression would be useless in a lot of applications. It's pretty easy to come up with a counter example.

E.g.

(simple huffman code off the top of my head, not optimal)

symbol -> code

"00" -> "0"

"01" -> "10"

"10" -> "110"

"11" -> "111"

If "00" will appear 99.999% of the time, and the other 3 symbols only appear 0.001% of the time, the output will "on average" be slightly more than half the length of the input.

Sure, I'm assuming that (a) you are trying to encode all strings of length at most n and (b) you have the uniform distribution over those strings. This makes sense in the original context of encoding random data.

you have the uniform distribution over those strings. This makes sense in the original context of encoding random data.

Lossless compression is nothing more than taking advantage of prior knowledge of the distribution of the data you are compressing.

Random data isn't always (or even often) uniformly distributed. Everything we compress is "random" (in the context of information theory), so I disagree that it makes sense to assume uniformly distributed data.

https://en.wikipedia.org/wiki/No_free_lunch_theorem

The indexes will, on average, have more digits than the sequence you compress. This is true for any infinite sequence of digits, not only Pi.

http://www.angio.net/pi/

My 11 digit phone number occurs around the 115 millionth digit, a grand saving of two digits.

Wow, isn’t there a really low probability of finding your phone number in the first 200m digits of pi? (0.09995% in first 100m) I’m tempted to start throwing a dictionary of phone numbers through this pi lookup to find your number, call you, and verify, I think you could quickly narrow in on your phone number given the information above.

I think you'll have trouble. Assuming the first digit of the phone number is somewhere between 114.5 million and 115.5 million, you have 1 million potential 11 digit numbers to check.

There are 10^11 sequences with 11 digits. The number of people in the USA is 3×10^8, and we can assume there is roughly 1 number per person (some people don't have a phone number and some people have more than one, but it turns out that the exact approximation won't matter unless we're a few of orders of magnitude off). So about 0.3% of 11 digit sequences are valid phone numbers.

So there are approximately 0.3% × 1000000 = 3000 people with phone numbers around the 115 millionth digit of pi. You have no way of knowing which one of those people is sjcsjc.

It'd be a great 1 person-audience magic trick to call up all 3000 of those people and say, "Hi sjcsjc, I found your phone number in Pi".

Derren Brown did a great series of tricks based on probability.. your comment reminded me on the one that showed a video of him flipping 10 heads in a row on an unbiased coin. He revealed them that he had done it by flipping a coin for hours until he got that sequence.

Or the machine language expression of the most advanced expert systems, though by then the notch might be small enough that Planck’s constant got in the way.

With Planck's length being roughly 10^-35m, I'd say you'd hit the limit trying to store more than 15 bytes.

This is insightful. 15 bytes is not a lot. I wonder what are other narural limits on information density? For example, magnetic field. Is there a least measurable difference?

Also depends on the length of the metal rod, doesn't it?

The observable universe is 2^205.5 Planck lengths across, so you can store at most 205 bits, or 25 bytes.

How are you calculating a value of simply 15 bytes? The proposal is that the mathematical value of the ratio of the lengths of rod and the notch will deliver a value on the number line, which in effect can be of any desired length. You actually could find a number that can represent the complete contemporary knowledge of Humanity.

The limitations mentioned in the above comment relate to the fact that to know you'd arrived at the number designed into the Notch and the Rod, you'd have to have agreed to beforehand the tolerance limits on measurement of this 'device' so that the uncertainty in measurement can be ignored and the ratio derived.

To maybe get the right number you would have to expand your possible number of ratios (at a certain measurement sensitivity you would have a certain number of lengths you could use, and thus certain number of ratios would be available to you) and to get just the right number to describe your whole "machine language expression of the most advanced expert systems" you would have to delve into tolerances of the Plank length.

Or adjust the size of your rod length and notch, make them bigger, to get that sweet number with a 'poorer' level of sensitivity.

.. Or find a number with enough usable number sequences to serve the purpose and program in the numbers surrounding gibberish as markers/jump points to the next sequence of usable numbers. I suppose you could find enough usable sequences in the full expression of pi (as it's rational expression is without end) to write a program that can decode the full linux kernel out of it.

Assuming the length of the rod is 1m, and you have a resolution of one plank length, there are 10e35 possible ratios you can express (because that's the number of possible locations of the notch). that's about 2^113, which is a number which fits in 15 bytes of information. As discussed below, if you also allow for the bar to be the size of the observable universe, this doesn't increase by much. A notch or ratio is linear, information and combinatorics grows a lot lot faster than that.

How would you say a rod to notch ratio of 22/7 compares? How much information would you say that has?

Meaningless on its own. What matters is how many distinct ratios are possible.

you can loosely think of it as writing down a number in unary where each "digit" takes 1.6 x 10^-35 m space to draw.

But what does that have to do with the emergent ratio between the notch and the rod? There may be 10^35 possible steps, but that does not mean that the answer, the ratio of the notch and the rod, will be limited by that. The answer will come from the number line, where any irrational number can have however many trailing numbers. If the ratio of the rod and the notch is 22/7, how much information would you say that is?

If 'x' marks the notch of a rod of length "1", [0---------x------------1], then the implied ratio is not x/(1-x), but x/1 (so the ratio is always < 1.) Even so, your question could be "what is the information content of 1/7" (the presumed implication being that 1/7, while periodic, has an infinite decimal representation.)

But that is not the direction we are interested in. We would like, given a message, such as "l-o-v-e", or 12-15-22-05, or 0.12152205, to figure out what is the ratio that uniquely specifies it. As we can only mark one notch, we can create "only" h ~= 10^35 ratios, or represent h unique messages. We know how to distinguish between h unique elements with log(h) bits (we just enumerate them from 1 to h and write that number down in binary.)

Let's assume that the rod is 1 m in length, and say I wrote a book that is perfectly represented by the number 0.abcdefg...yz. If that number is perfectly represented by one of the ratios in set 'h', then have I not stored more infromation than 15 bytes?

As for x/(1-x), why not? And why limit ourselves to a 1 m rod? Why not a 22 m rod with a 7 m notch? I could then define the method of decoding the information via (Rod length)/(notch length). The I'd have 'infinite' information in the form of expression of pi.

My main issue with the parent comment is that they imply only 15 bytes of data could be stored via this method. I think that's prespoterous as the number of ratios my be only 15 bytes, the ratios themselves can have any possible size.

It becomes more a game of probability rather than that of exact numbers. Will you find the right number, from set 'h', that matches exactly what you wanted to say?

    0.abcd...xyz = [(notch length=alpha*plank length)/(rod length=beta*plank length)]

where alpha and beta are just any variables that you play with until you solve the equation.

Not really. You have stored something which has a representation of more than 15 bytes, but you will struggle to find a way to store most things longer than 15 bytes in this way. (everything can be transformed into a representation which is infinite in size anyway, for example by using an irrational base). Information really comes down to the number of possible values you can distinguish.

If you do the ratio thing you have described you will find that alpha and beta are many, many times the size of the observable universe for something like a book. If you allow the length of the rod itself to also contribute to the information, you have added another symbol so you can store more than 15 bytes, but this doesn't even double the amount of bytes you can store.

As someone that develops almost exclusively in high-level languages on top of may levels of abstraction, it's nice to see what can be accomplished close to the metal.

This reminds me of Steve Gibson's SpinRite, which (from what I recall) is a fully functional disk recovery utility written entirely in assembly. https://www.grc.com/spinrite.htm. Say what you want about the man, but this is something that's saved me on at least one occasion, and is smaller than things I produce that do a lot lot less.

There are people that will argue until they are blue in the face that his recovery software is useless.

But I have also had some success with it.

Everything that he releases is amazingly tiny. It just shows how much bloat modern software tends to have.