OTOttoCoddo·Mar 23, 2024
Hello David, and thank you for your comment, analysis, and the issues you opened. I will get to them all.
- SQLite tooling: You will not need it unless you are debugging something, then you can change the header or just use the `--activate-other-options --transform-to-sqlite3` parameter to transform a Pack file to SQLite3, and use the `--activate-other-options --transform-to-pack` to go back. This way, you get a true SQLite3 database that you can browse as you wish. For most people, mixing Pack with SQLite was just a call for problems for the SQLite team (imagine people coming and asking to fix their Pack file from the team; that would not be fair) and a harder future for Pack to update.
- Metadata is not stored in Pack. I don’t want the metadata of my machine attached to a file. It’s a never-ending nightmare to match source and destinati
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on OS metadata. There will always be something missing, and Pack tends to get everything perfect or nothing. Storing metadata adds extra weight that most users don’t care about and complicates the ability to store other types of data alongside files. It may get added as an option in the future if many people need it.
- There is a version field. It is currently in Draft 0, and it is written using a custom VFS. Look here for more information: https://github.com/PackOrganization/Pack/blob/main/Source/Dr...
- All future versions of Pack must handle previous versions and must only write the latest version. So any files created right now (Draft 0) will be read correctly for ever to come.
- Each Draft proposal will get its own version, and if it gets final, it will be set to final.
- Two byte after 'Pack' header in little endian as (1 (Draft) shl 13 + 0 (version 0) = 8192). Final would be 0, so the first Final version will be 0 shl 13 + 1 = 1. and the second will be 2. It is by design, so any Draft version gets a higher number, preventing future mixups.
- 8 MB chunks are the default; Pack may choose smaller or bigger (16 MB for many small files or 32 MB for Hard Press).
- Random access is proper as unpacking steps take into account what you want and decompress a Content just once for many neighbouring files. But even for reading just one file, here is an example: if I want to extract just a .c file from the whole codebase of Linux, it can be done (on my machine) in 30 ms, compared to near 500 ms for WinRAR or 2500 ms for tar.gz. And it will just worsen when you count encryption. For now, Pack encryption is not public, but when it is, you can access a file in a locked Pack file in a matter of milliseconds rather than seconds.