The filesystem that stores nothing: πfs keeps your files in the digits of pi
It's a joke with a real CS lesson inside. πfs claims to store any file by finding its bytes as an offset into pi — 'you'll never run out of space again.' The thread turns it into a tour of why this can't possibly compress anything.
The README's deadpan is the point: 'Copyright infringement? It's just a few digits of π! They were always there!'
The CS punchline: the offset into pi needed to locate your data is, on average, as long as the data itself — so it's a perfect demonstration of why it fails.
The joke, stated with a straight face
πfs is a "data-free filesystem." The conceit: because pi is conjectured to be a normal number — its digits containing every finite sequence somewhere — any file already "exists" inside pi. So instead of storing your bytes, πfs stores the offset where those bytes appear in pi's expansion, computed with the Bailey–Borwein–Plouffe formula. The README commits to the bit completely:
"You'll never run out of space again — π holds every file that could possibly exist!"
"Copyright infringement? It's just a few digits of π! They were always there!"
"Why is this thing so slow? It took me five minutes to store a 400 line text file! … there's always Moore's law!"
The thread is a free information-theory seminar
What makes this more than a chuckle is that the comments calmly explain why it's impossible — which is the actual educational payload. The cleanest statement of the flaw:
"I'm intrigued… it becomes extremely unlikely that the index and length of the sequence within pi would actually be smaller than the data." — adzm
Someone who'd chased this exact rabbit hole connected it to the foundational result:
"Reminds me of when I tried to use the library of babel as a data compression tool. … 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." — jamwise
And a regular linked the formal version, quoting the key line: "Matches that occur early enough in π to attain significant compression will not be varied … it isn't possible to use π to compress interesting, real-world data because real-world strings are unlikely to arise early," from a CS StackExchange answer.
The same trick, weaponized for real
The funniest connection was to an actual benchmark exploit — gaming a compression contest by smuggling data into the filename, the same sleight πfs makes explicit:
"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." — aidenn0
It also has a lineage. dang, the site's moderator, listed the half-dozen prior appearances going back to 2018, and one regular pointed to the repo's GDPR-compliance issue as the canonical bit — because of course pi contains everyone's personal data.
Why a 12-year-old joke keeps coming back
πfs endures because it's the rare gag that teaches the thing it parodies. The instinct "store the address instead of the data" is exactly how real systems do save space — deduplication, content-addressable storage, pointers. πfs pushes that instinct to its breaking point and lets information theory do the rest: the address is as expensive as the thing it points to. It's a one-line refutation of every "infinite compression" pitch, wrapped in a working FUSE filesystem that will cheerfully take five minutes to save a text file.
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