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Show HN: Arc – secure file archiver

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Re: Show HN: Arc – secure file archiver

#41

Post by kakwa_ »

valarauca1 wrote: post #9
josho wrote: post #6

This is the first that I've heard of ChaCha for encryption ( https://en.wikipedia.org/wiki/Salsa20#ChaCha_variant ). Apparently it's a standard that Google is pushing to replace RC4 and already is using for HTTPS between google.com and Android. If arc catches on I'm curious if it could support inline operations. E.g. on a 100gb+ archive can I read the tar index without decrypting the entire archive first, can I extra…

If you are seriously concerned with the effects of Bit Rot on long term storage I suggest you invest in Magnetic Tapes. Which can be insured against bit rot for >300 years (Yes IBM and Oracle sells insurance for this, but only on IBM tape's/decks, they'll also have to inspect your storage facility). With highly specialized requirements comes highly specialized solutions.

The tapes themselves could last 300 years (or, for more realistic common needs, around 30 years).

However the tape reader/recorder will probably not last that long. These things need special care (don't forget the cleaning tape every other month) and can act a little weird when the mechanical parts wear down (or even before in many cases).

The Ultrium LTO standard states that a tape recorder for version N must read/write N-1 and read N-2. Given that there is a new version around every 3 years, it gives you around 10 years of strong guaranty on your capacity to actually recover your data.

To properly manage data on a longer period you need to migrate the data to a new media. In fact, the problem then became mostly organizational.

Re: Show HN: Arc – secure file archiver

#42

Post by qwertyuiop924 »

StavrosK wrote: post #30

Can anyone tell me what advantage tgz has over zip? I usually curse when I have to use it, because it lacks indexes and is pretty much only good for archival tapes, if that. I wish we'd all move to a more modern format, like zip or 7zip.

Zip compresses each file separately. A folder full of zip files, each containing a single file, should take up roughly the same space as a zip archive containing all of the files. tgz doesn't do this, so it has a higher compression ratio for large collections of files. However, you cannot extract a single file alone from a tgz archive. This is why zip was designed the way it was.

Re: Show HN: Arc – secure file archiver

#43

Post by qwertyuiop924 »

The name arc has namespace collision problems. Not in software in general (I never complained about somebody calling their language elm - that's Cantrill's job), but in archivers in particular. Arc was the format that directly preceded zip, pkzip being the program that pk started selling after it was discovered that pkarc's source code was copied verbatim from the source for the original arc utility.

Re: Show HN: Arc – secure file archiver

#44

Post by _swa8 »

_swa8 wrote: post #13
Longhanks wrote: post #2

Not a very creative name. There is enough IT related products with the name Arc already.

Not only that, there's a historical program called Arc that is also a file archiver/compressor. It led to PKZIP.

Come to think of it, a variant of it is still packaged in Debian, package is called "arc".

Incidentally, for anyone choosing a name, the namecheck program from the Debian devscripts package is handy for checking if a particular name is already in use. Not perfect, but handy anyway.

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