[apjana]

I can think of at least 3 possible algorithms to use much much less memory even with a static snapshot of the complete subtree. And all of them are broken because the filesystem is supposed to stay online and change. It's realistically useful to scan an external disk to find the largest file etc., but not accurate on a live server, a desktop with several ongoing downloads, video multiplexing etc.

[propa]

Earlier in the thread you suggested that it's hard to justify ncdu using 60MB while it takes only 3.5MB to store 400K * 8 bytes numbers. The number you came up with is just silly and overlooks actual complexity of the problem.

Given that you are making an implicit judgement about the other program, don't be sloppy with your estimates.

[apjana]

> don't be sloppy with your estimates

I'm not. You can, and I'm sure eventually you will arrive very close to the approximation.

I'd been a big time fan of `ncdu` for years and even wrote in an e-journal about it once. Maybe that's why the sharp adjectives became more difficult to digest. Anyway, good luck!