A bootable CD image with a retro game in a single tweet

https://www.quaxio.com/bootable_cd_retro_game_tweet/

by chetanhs • 8 years ago

1004 140 8 years ago

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

vinhboy• 8 years ago

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.

amenghra7• 8 years ago

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...

classichasclass• 8 years ago

There's almost as much header information as there is code!

barbegal• 8 years ago

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.

garaetjjte• 8 years ago

Not CD images, but there is DOS C compiler generating executables with only printable characters (and also no self-modifying code that could contain non-printable characters)

http://www.cs.cmu.edu/~tom7/abc/paper.txt (view in monospace font, 160 character lines)

mirimir• 8 years ago

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

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

raphlinus• 8 years ago

Machine readable as well as machine washable[0]!

[0] http://cypherpunks.venona.com/archive/1995/10/msg00317.html

cheeze• 8 years ago

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

makomk• 8 years ago

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

wtmcc• 8 years ago

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

SlowRobotAhead• 8 years ago

Took me a second to figure out after looking at the assembly that it's possible because of base64.

gerdesj• 8 years ago

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

.. and way smaller than your comment .

pard68• 8 years ago

I looked at the that tweet for five or six minutes and was stumped. Now this makes more sense, thanks.

0xcde4c3db• 8 years ago

Most of the "compression" is zero bytes due to fixed offsets of various things (e.g. the first 16 sectors of an ISO 9660 image are a "system area" not used by the actual file system).

arcticbull• 8 years ago

Yeah, it's a really simple run-length encoded ISO expressed as a Perl script.

narrator• 8 years ago

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

bvc35• 8 years ago

What's real mode?

gknoy• 8 years ago

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

saagarjha• 8 years ago

what we have now

x86 processors still boot into real mode…

yjftsjthsd-h• 8 years ago

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

ghamrick• 8 years ago

I grew up (career wise) on CTOS systems with 286/386 processors that could address the full 16MB in protected mode without memory extenders or expanders that were available for DOS back in the day. Also premptive multi tasking. It was a great OS to learn on. more info - https://web.archive.org/web/20080828190425/http://www.byte.c...

starpilot• 8 years ago

Wow, that's pretty leet.

yebyen2• 8 years ago

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.)

amenghra7• 8 years ago

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

reificator2• 8 years ago

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

yebyen2• 8 years ago

Woops... I skimmed the article and watched the 30MB GIF

collinmanderson• 8 years ago

Tron is a great game for fitting into a very small space. Back in high school I spent a lot of time optimizing Tron on the TI-82 to fit in as few bytes as possible. It looks like I got it down to 152 bytes: (only about 80 bytes of actual Z80 assembly code)

https://www.ticalc.org/archives/files/fileinfo/227/22747.htm...

wvh• 8 years ago

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!

exikyut6• 8 years ago

You just reminded me of an old game that made "snow" for the screen by copying a specific location on the disk into video memory.

myth_drannon• 8 years ago

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

acutesoftware• 8 years ago

nice to see demos in action without running random code - thanks. Demos are without a doubt the best way to show the maths can look cool.

ryandrake• 8 years ago

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.

notyourwork• 8 years ago

There is something to the saying "less is more".

sgillen• 8 years ago

For sure, although as a counterpoint I’ve also seen programmers do the reverse. Spending a lot of effort building bad abstractions to completely minimize code reuse/size, when really we would have been better off with slightly longer code that was clearer and that meshed better with our problem domain.

icebraining• 8 years ago

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

flas9sd• 8 years ago

that made me chuckle, judging from the whole idea, it's part of the fun

mynewtb• 8 years ago

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

varjag• 8 years ago

The actual tweet: https://twitter.com/alokmenghrajani/status/10075143375929876...

rootbear• 8 years ago

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

amenghra7• 8 years ago

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

mygo• 8 years ago

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

a1k0n• 8 years ago

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.

amenghra7• 8 years ago

For those who don’t know, x86 had support for binary coded decimal (you end up wasting a bunch of bits).

AAA converts the result of the addition of two valid unpacked BCD digits to a valid 2-digit BCD number.

wintorez• 8 years ago

What is this sorcery!?

fmfamaral• 8 years ago

Well done, sir.

amenghra7• 8 years ago

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/

CGamesPlay• 8 years ago

You should investigate adding an RSS feed!

Klathmon2• 8 years ago

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.

amenghra7• 8 years ago

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

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

Klathmon2• 8 years ago

IIRC weren't the Twitter length changes only applied to languages that weren't benefiting from the more "dense" encodings.

Meaning languages like Chinese and Japanese are still at the old limit.

lucb1e4• 8 years ago

Multibyte chars is optimizing for Twitter, not for a set amount of bytes. If you try to fit in 140 bytes and you use >140 bytes because they are multibyte chars, then yeah, you're cheating. But if you're trying to "fit in a tweet", I'd say that's perfectly fair game.

Anyhow, two games... cool, but to be perfectly honest, I thought the game was going to be more like the real snake than just drawing a non-overlapping line on screen. A more impressive game might be more impressive than two games.

Then again, two games is also pretty darn cool.

komali2• 8 years ago

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?

tomcam• 8 years ago

Yes, they are copyrighted. The link to article points to this equivalent, free ECMA 119 standard: https://www.quaxio.com/files/2018/bootable_cd_retro_game_twe...

robinwassen• 8 years ago

I bought the ISO 14000 Standard Document (Environmental Management) for $170 earlier this year, so it is not expensive for a company. Not sure how the "technical documents" ala ISO 9660 differs in price.

The certification on the other hand is a bit more costly though. My estimation of the certification cost for a ~20 people company if you do it as frugally as possible ended up at $18000 for the first year investment, and $6200 recurring the following years.

tomxor• 8 years ago

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

amenghra7• 8 years ago

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...

BGZq7• 8 years ago

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.

jobu• 8 years ago

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.

dfcarney• 8 years ago

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

utopcell6• 8 years ago

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

haser_au• 8 years ago

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.

troupe• 8 years ago

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."

amake• 8 years ago

Here's an implementation of precisely that, as a filesystem:

https://github.com/philipl/pifs

Discussed here previously (2014):

https://news.ycombinator.com/item?id=8018818

praptak• 8 years ago

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.

sjcsjc• 8 years ago

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

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

magnat• 8 years ago

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.

hamilyon2• 8 years ago

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?

Tepix• 8 years ago

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

jtrip6• 8 years ago

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.

gballan• 8 years ago

Reminds me of 'pulse position modulation' [1].

[1] https://en.wikipedia.org/wiki/Pulse-position_modulation

billpg• 8 years ago

You could split the package of data into chunks and place multiple notches on the bar. You'd need to include enough information to allow the chunks to be sorted into their original order for that to work.

As if this were a practical means of storing data.

jhbadger• 8 years ago

The late mathematics popularizer Martin Gardner wrote about this concept in the 1970s (I think his example involved reducing the Encyclopedia Britannica to a notch), although I don't know if the idea was unique to him or if he was popularizing an earlier idea.

utopcell6• 8 years ago

So beautifully retro. Like twitter :-)

KyeRussell• 8 years ago

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.

jjeaff• 8 years ago

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.

exikyut6• 8 years ago

What I've read is that SpinRite simply just reads and writes to the disk, triggering the disk firmware to reallocate bad sectors. I think it just tries to read many times, which can sometimes help.

The other argument is that the various things SR tries to "manage" (sector interleave, getting various timing parameters "perfect", etc) were only relevant with ST-506 (!!) and similar disks from the 80s/very early 90s, and that anything remotely modern (even IDE, virtually 100% of SATA) generally doesn't provide enough low-level control surface that trying to micro-manage the disk's behavior will do anything particularly special.

Of course, I'm sure each manufacturer has their own tools and widgets that can use undocumented proprietary SATA/SCSI commands to control the drive's behavior at a very low level, but those kinds of tools are a) rare as hens' teeth and b) probably very easy to break disks with due to poor UI design and lack of documentation. Chances are the most expensive data recovery centers probably have some of these tools, and more importantly the training to know how not to kill HDDs with them :P

TL;DR: Yes, SR works, but probably just as well as dd3rescue; as always, if you think a disk is this side of dead and you think you have a chance without specialized tools, just imaging it is probably the best first step, because SR and all other tools will of course stress it.

With all of this said, I really, really like SR's startup animation :3 and I agree that it's refreshingly small.

sjtrny• 8 years ago

The explanation is quite good but is there even more detail on what the assembly instructions are doing on a line by line basis? I’ve only written MIPS assembly and that was a long time ago.

andyidsinga• 8 years ago

i love love love this.

This is a fantastic way to get into low level programming with a fun,tangible and approachable result.

back in "the day (TM)", we used to do this with ..achem ..viruses on floppies :) Putting it in a tweet is just brilliant.

anyone remember the one where it would say "smoke more weed dude"? (or something of the sort) :)

xellisx• 8 years ago

Not as cool as this, but here are some PHP "frameworks" in a tweet (140 characters):

http://www.twitto.org/

https://gist.github.com/mathiasverraes/9046427

https://philsturgeon.uk/php/2009/12/15/Twiny-Framework-the-f...

https://gist.github.com/jeremeamia/2720020

wojtczyk• 8 years ago

Love it!

A bootable CD image with a retro game in a single tweet

Related Stories