πFS

363

hhelterskelter about 4 hours ago 99 commentsRead Article on github.com

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jamwise•about 2 hours ago

Reminds me of when I tried to use the library of babel as a data compression tool. It led me down a fun rabbit hole and was my first introduction to information theory.

The conclusion being that you basically need the same amount of data to represent the address of your data as the data itself, so it's not really effective at compression, just a fun thought experiment.

The cool part of this in modern times is that LLMs are basically a form of lossy compression that actually achieves the gist of what these tools fail at. Although it is lossy, and requires a massive substrate. This is related to the idea of AI/LLMs being a form of language compression.

quirino•16 minutes ago

3Blue1Brown just released a viduo about this Intelligence-Compression connection.

https://youtu.be/l6DKRf-fAAM

jamwise•12 minutes ago

The idea was fresh in my mind because I watched this yesterday. Great video, the illustrations and intuition-building of the compressability of information was so good! I'm so grateful for 3Blue1Brown.

emptyroads•about 1 hour ago

Reminds me of nsafs, the National Security Agency Filesystem ("free" because the government pays for it) - https://github.com/freedomtools/nsafs

dekhn•9 minutes ago

I once interviewed for a company and the interviewer was telling me how he (a vc) funded a project to generate large streams of random numbers; you would select an index at random, share that private key with somebody, and then the subsequent text could be used as a one-time-pad. NSA would be forced to buffer/save the entire stream, which could be generated at GB/sec, if they wanted to decrypt.

It didn't seem very practical.

adzm•about 2 hours ago

It is worth noting that as the length of data increases it becomes extremely unlikely that the index and length of the sequence within pi would actually be smaller than the data.

Aloisius•about 2 hours ago

That seems easy enough to solve. Simply record the index and length in pi of the index and length in pi.

awesome_dude•about 2 hours ago

See also: Recursion

liamYC•19 minutes ago

Point taken about the index potentially being really long. Why would the length be longer than the data? Don’t you need to find the right sequence?

mondrian•about 2 hours ago

The index of your 20 line file is <20TB number>

russfink•7 minutes ago

Unless, in turn, you locate the index itself in pi at a much smaller index. And so on...

Find k candidate indices for your data, then locate each of them. If the smallest one is a significantly smaller index space, repeat.

12_throw_away•about 2 hours ago

yes I believe that's the joke

jwpapi•about 2 hours ago

He’s aware, he just added some curious information.

dang•about 2 hours ago

Related. Others?

πfs – A data-free filesystem - https://news.ycombinator.com/item?id=36357466 - June 2023 (107 comments)

πfs – A data-free filesystem - https://news.ycombinator.com/item?id=28699499 - Sept 2021 (30 comments)

PiFS – The Data-Free Filesystem - https://news.ycombinator.com/item?id=26208704 - Feb 2021 (1 comment)

Πfs: Never worry about data again - https://news.ycombinator.com/item?id=21359338 - Oct 2019 (1 comment)

The π Filesystem for FUSE: Store Your Data in π - https://news.ycombinator.com/item?id=19223032 - Feb 2019 (1 comment)

pifs - Avoid disk space usage by saving your files in the digits of Pi - https://news.ycombinator.com/item?id=18687275 - Dec 2018 (1 comment)

πfs – A data-free filesystem - https://news.ycombinator.com/item?id=13869691 - March 2017 (105 comments)

Πfs: Stores your data in π - https://news.ycombinator.com/item?id=10856108 - Jan 2016 (1 comment)

Πfs: Never worry about data again - https://news.ycombinator.com/item?id=10847693 - Jan 2016 (1 comment)

File system that stores location of file in Pi - https://news.ycombinator.com/item?id=8018818 - July 2014 (98 comments)

100% Compression Using Pi - https://news.ycombinator.com/item?id=6698852 - Nov 2013 (32 comments)

(Reposts are fine after a year or so; links to past threads are just to satisfy extra-curious readers)

Levitating•about 2 hours ago

How are you generating these lists

dang•35 minutes ago

See https://news.ycombinator.com/item?id=44861185 and the links back from there.

programjames•about 2 hours ago

If you click the website's name to the right of the title, it pulls up all the submissions from the same site:

https://news.ycombinator.com/from?site=github.com/philipl

Levitating•about 2 hours ago

Even then I don't see a direct way to extract a list like this.

jwpapi•about 2 hours ago

He’s the mod hero from HN

windward•24 minutes ago

>One of the properties that π is conjectured to have is that it is normal

conjectured

Glad to see one of my pet points of pedantry come up. No non-constructed irrational number has never been proven to be normal or disjunctive.

oofbey•14 minutes ago

That’s a lot of negatives!

mikestew•6 minutes ago

One of which probably needs to go away.

MisterTea•about 2 hours ago

Reminds me of: https://www.spronck.net/sloot.html

Further reading: https://en.wikipedia.org/wiki/Sloot_Digital_Coding_System

ndiddy•7 minutes ago

I looked into this a bit a while ago, what Sloot did was at least a bit novel. Basically the way his encoding scheme actually worked was that it would store each line of video into a database, encode each video frame as a series of line lookups, and then store that encoded frame into another database. Then each video is a series of frame lookups. When you hear accounts of him being able to demo smooth playback of 16 videos at once on late 90s hardware, this is how he did it. Because each frame is a series of line lookups, splitting the screen horizontally 16 times and playing 16 videos at once is not any more taxing than playing a single video fullscreen. Similarly, he was able to fast-forward and rewind smoothly because each frame is individually decoded, it's not like traditional video compression where you have to calculate differences from each keyframe. Playing at 2x speed was not any more taxing than 1x speed. Of course he never would have been able to store a video file in 8KB or whatever, but this meant that (for example) if you had a whole season of a TV show in your database, the opening and ending credits would only be stored once.

Levitating•about 1 hour ago

> The SDCS is only possible if keys are allowed to become infinite, or the data store is allowed to become infinite (...) This would, of course, make the idea useless.

But Pi is infinite. And thus this genius contraption will work as long as we have Moore's law on our side :)

beng-nl•about 1 hour ago

I have very fond memories of reading that book.

giancarlostoro•about 2 hours ago

Never heard of that one, that's amazing! Love it.

bilsbie•13 minutes ago

I’d guess even the index in pi for my phone number would be more digits than the phone number.

So not really a compression scheme.

nyc_pizzadev•34 minutes ago

Just a heads up, this is writing 16 bits for every 8 bits of input:

https://github.com/philipl/pifs/blob/fded8bf7b8f4fc64233e37b...

bobim•about 3 hours ago

This is disturbing to realize that pi then contains all the past and future knowledge, including when I'll pass away.

mike_hock•about 2 hours ago

So does every other random infinite sequence of bits. The unintuitive part comes from infinity, not pi.

It also doesn't contain all past and future knowledge because it also contains all possible falsehoods about the past and future in a way that's indiscernible from the truth.

Encoding information as an offset into a pseudorandom sequence is no more storage efficient than storing the information directly.

sph•about 2 hours ago

Are you aware this is meant as a joke, right?

LoganDark•about 1 hour ago

Jokes can be educational too.

nosioptar•about 2 hours ago

The worst part is that it contains Star Wars 4-6 from an alternate timeline where Disney did a reboot casting Chris Pratt as Han Solo.

(Fun fact: "Chrispratt" is an ancient Californian word that means "Joel McHale didn't want the role.")

Yokohiii•about 1 hour ago

Around here it just means chrisp ratt.

1attice•about 2 hours ago

Thank you for this Prattfall

arialdomartini•42 minutes ago

You will love reading Jorge Borges The Library of Babel.

https://dn760100.eu.archive.org/0/items/TheLibraryOfBabel/ba...

Yokohiii•about 1 hour ago

The person who starts reading ahead into pi will always gets the freshest numbers.

Perfect crypto!

xp84•about 1 hour ago

If it makes you feel better, consider that it also contains all plausible and implausible falsehoods about your demise as well.

cadamsdotcom•about 2 hours ago

Fear not! It’s probably so deep in pi that you’d pass away listening to someone tell you where!

thih9•about 2 hours ago

It also contains all possible falsehoods and comes with no way to distinguish what's true from what isn't.

vadansky•about 1 hour ago

But enough about LLMs

OkayPhysicist•about 2 hours ago

So does a calendar, if you you buy them enough years in advance.

nighthawk454•about 2 hours ago

And also all the days you don’t, so, by itself not very meaningful. Especially since you can’t tell which one is right in advance. In some sense, so does a calendar

skulk•about 2 hours ago

this statement is equivalent to "pi is a normal number." While most real numbers are normal and pi is suspected to be so, it isn't known.

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

anthonj•about 2 hours ago

So does a random number generator

koolala•about 2 hours ago

It isn't actually proven true.

aidenn0•about 2 hours ago

I vaguely remember an entry to a compression-benchmark that gamed the benchmark by treating the filename as part of the input to the decompression-algorithm, thus beating the metric that only measured the size of the file.

partsch•about 3 hours ago

Finally, someone is doing something about the rising prices of storage!

z3t4•29 minutes ago

Someone should make a service "where in the pi am I" then you could use it as a short link. Then there will be hardware accelerated pi chips. All computers will come with pi preinstalled.

chris_sn•27 minutes ago

Funnily enough I’m reading Service Model and just got to the bit in the Library Archive, which has a very similar vibe to this project. Love it

yassi_dev•32 minutes ago

I built something with a similar spirit for Pi day: https://pi.yassi.dev/

Lalabadie•about 3 hours ago

Love it! This feels very much in the spirit of Tom7's Harder Drive [1]

[1] https://www.youtube.com/watch?v=JcJSW7Rprio

thangalin•about 2 hours ago

https://cs.stackexchange.com/a/53737/1704

> Matches that occur early enough in π to attain significant compression will not be varied. That is, it isn't possible to use π to compress interesting, real-world data because real-word strings are unlikely to arise early.

Levitating•about 2 hours ago

> Since the file is 128 bits long, one would expect this place to be around the 2*128th bit.

> Calculate the number of bits to encode that value using log2(938933556), which is ~29.8

Can someone explain these two statements to me?

csunoser•about 1 hour ago

for > Calculate the number of bits to encode that value using log2(938933556), which is ~29.8

This is roughly same as saying: "If you rewrite 938933556 as a binary number / usize, it will need 30 bits".

Sanity check: 1101111111|0110111111|0100110100 (| delimits every 10 bigits).

> Since the file is 128 bits long, one would expect this place to be around the 2*128th bit.

This statement is a bit more subtle. As a first ord approximation, we can see pi sort of as a RNG.

If we write pi (ignore the decimal point), as a binary number, we get: 11011001111111011110010101011110001010101111101101110001001100001...

You can... kind of squint and pretend this is a random sequence of 1s and 0s.

Now, if you had a file that is 128 bits (so lots of intermingling 0s and 1s), and each next digit of pi is effectively a coin flip. Pretend 1s are heads, and 0s are tails. You basically have to get the exact 128 consecutive coin flips of the same result as your file to get your file back.

Imagine now, PI not as a number, but a sequence of experiments of flipping the coin 128 times.

  - (11011..01000)(10000...00100)....
  - ^attempt 1     ^attempt 2

You have to try, on expectation, quite a few times to win this game! Now, you could easily get lucky for sure. But on average, your chance of winning per attempt is roughly 0.5^128! So, how many times do you have to try to win this game? Something like 2^128 times - and you have to consider that each attempt uses 128 bits as well. So more like 2^135. But you don't have to start fresh in each attempt, you can see it as like this:

  - 11011................00100...
  - (       128 flips     )
  -  (  another 128        )
  -   (                     )
  -     ... so on and so on

That's where the 2^128 number came from.

Levitating•42 minutes ago

Thank you!!!

woah•28 minutes ago

I've simplified it and made it more flexible

3._1_415926535897932384626433832795_0_288419716939

giancarlostoro•about 2 hours ago

I... I can't tell if this is an elaborate troll or pure genius. I love it.

pokstad•about 2 hours ago

Both.

tptacek•about 3 hours ago

https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...

koolala•about 2 hours ago

Short Storage Number - SSN

0x123456789ABCDEF0

use this number as a shorter nibble storage alternative...

actusual•about 1 hour ago

This is why I got pi tattooed. It's a tattoo of all tattoos.

hnlmorg•about 2 hours ago

This is probably a dumb question, but do we actually know that pi has an infinite number of decimal digits or are we assuming that it does because we haven’t developed a sufficiently powerful computer to calculate the last digit of pi?

I’m guessing this is something that could be formally proven?

hasteg•about 2 hours ago

Here is a one page proof that pi is irrational - https://heuklyd.github.io/papers/pdf/Niven-1947.pdf

simonreiff•21 minutes ago

For a superb explanation of Niven's proof (which leaves more questions than answers when you first read it), I like Michael Penn's video: https://youtu.be/dFKbVTHK4tU?is=d2DbV5HDP0IpP9tA ....notwithstanding the length of the proof, this is quite a hard problem.

partsch•about 2 hours ago

Thanks for the PDF. I feel like I understand even less now than I did before.

hnlmorg•about 2 hours ago

Thanks for sharing. That’s a nice read. I’m glad I asked :)

stackghost•about 2 hours ago

It's amazing how inscrutable calculus can be when you return to reading it after not doing so for a period of time, much like lisp or forth. I don't think I've actually done an integral or taken a derivative in years. I can see the elegance of that proof but I'll be damned if I can actually follow the mathematics from one step to the next.

mike_hock•about 2 hours ago

We definitely know that Pi is irrational, we just don't know if it's normal (i.e. if the PiFS joke even works).

pixel_popping•about 2 hours ago

Well, that should get GPT-5.5 extended thinking going for a few weeks.

adzm•about 2 hours ago

I'm intrigued that π was capitalized to Π presumably automatically in the HN headline.

cbm-vic-20•about 2 hours ago

    jshell> "πfs".toUpperCase()
    $1 ==> "ΠFS"

    Welcome to Node.js v26.3.0.
    Type ".help" for more information.
    > "πfs".toUpperCase()
    'ΠFS'

    Python 3.14.5 (main, May 10 2026, 10:21:34) [Clang 21.0.0 (clang-2100.0.123.102)] on darwin
    Type "help", "copyright", "credits" or "license" for more information.
    >>> "πfs".upper()
    'ΠFS'

    echo 'πfs' | awk '{print toupper($0)}'
    ΠFS

noman-land•about 2 hours ago

Why does your Python terminal report May 10th? Today is June 10th.

atvrager•about 1 hour ago

It's the build date of their Python binary

Yokohiii•about 1 hour ago

He prepared the comment a month ago.

danlitt•about 1 hour ago

Probably daylight savings

amluto•about 2 hours ago

> Why is this thing so slow? It took me five minutes to store a 400 line text file!

> Well, this is just an initial prototype, and don't worry, there's always Moore's law!

Seriously? They're only storing individual bytes in pi:

> In this implementation, to maximise performance, we consider each individual byte of the file separately, and look it up in π.

So the whole transformation should be trivially reducible to a 256-element lookup table from source byte to location in pi and a similar table used to convert back the other way. Maybe a fancy formula could be used for the (never actually encountered) case in which a byte is encoded by one of the infinite available noncanonical encodings.

glitchc•about 2 hours ago

At what point is the metadata larger than the actual file?

wavemode•about 2 hours ago

Part of the joke is that, in this implementation, the metadata is guaranteed to be larger than the file:

> Now, we all know that it can take a while to find a long sequence of digits in π, so for practical reasons, we should break the files up into smaller chunks that can be more readily found.

> In this implementation, to maximise performance, we consider each individual byte of the file separately, and look it up in π.

mike_hock•about 2 hours ago

Half the time it should be larger, right?

charles_f•about 2 hours ago

Posted many times before: https://news.ycombinator.com/from?site=github.com/philipl

My favourite issue being about GDPR compliance https://github.com/philipl/pifs/issues/56

anon291•about 1 hour ago

It is actually not proven that the decimal expansion (or any rational base expansion) of pi contains all possible sequences of numbers. It sounds like it intuitively would be since the expansion is infinite, but it is not necessarily true. For example, the number 0.101001... (i.e., decimal formed by concatenating N zeros and then 1 for all N 0 to infinity) is infinite, never-ending, and irrational but does not contain every sequence of numbers.

leephillips•about 2 hours ago

What a brilliant idea! Of course, of course, it’s not in the repository so I can’t apt-get install it. Debian...always so far behind.

j3th9n•about 2 hours ago

Why would anyone need πfs, since you can already build such a system yourself quite trivially on Linux.

Levitating•about 3 hours ago

absolutely genius

mzelling•about 1 hour ago

Looked at the repo but it says NOTHING about what value this project offers.

I mean, I get that it's "fun" to store information within the digits of pi. But is this just amusement, or is there a value prop for production use here?

(Speaking as a math major, by the way. I'm sympathetic to the cause.)

windward•20 minutes ago

It's a(n IMO weak) argument raised when discussing illegal files/numbers.

This project makes clear the counter-argument: the input that gets you the file out of π is a badly compressed version of the file.

tcoff91•about 1 hour ago

I think it's pretty clearly for amusement. And it would kind of spoil the amusement if it were to explicitly mention that it's a joke...

mherkender•about 1 hour ago

It's a joke.

spchampion2•about 1 hour ago

This is interesting, but I feel like my use cases would better align with a different irrational number. Could I get an option to do this with e instead? /s