Hacker News Reader

Comment by MereInterest | Hacker News Reader

Splitting the file doesn’t need to be part of the file format itself. I could split a file into N parts, then concatenate the parts together at a later time, regardless of what is actually in the file.

The OP was saying that zip files can specify their own special type of splitting, done within the format itself, rather than operating on the raw bytes of a saved file.

View on HN

> Splitting the file doesn’t need to be part of the file format itself. I could split a file into N parts, then concatenate the parts together at a later time, regardless of what is actually in the file.

I'm inclined to agree with you.

You can see good examples of this with the various multi-part upload APIs used by cloud object storage platforms like S3. There's nothing particularly fancy about it. Each part is individually retry-able, with checksumming of parts and the whole, so you get nice and reliable approaches.

On the *nix side, you can just run split over a file, to the desired size, and you can just cat all the parts together, super simple. It would be simple to have a CLI or full UI tool that would handle the pause between `cat`s as you swapped in and out various media, if we hark back to the zip archive across floppy disks days.

Without knowing the specifics of what's being talked about, I guess it makes sense that zip did that because the OS doesn't make it easy for the average user to concatenate files, and it would be hard to concatenate 10+ files in the right order. If you have to use a cli then it's not really a solution for most people, nor is it something I want to have to do anyways.

The OS level solution might be a naming convention like "{filename}.{ext}.{n}" like "videos.zip.1" where you right-click it and choose "concatenate {n} files" and turns them into "{filename}.{ext}".

> the OS doesn't make it easy for the average user to concatenate files

Bwah! You are probably thinking too much GUI.

    X301 c:\Users\justsomehnguy>copy /?
    Copies one or more files to another location.

    COPY [/D] [/V] [/N] [/Y | /-Y] [/Z] [/L] [/A | /B ] source [/A | /B]
         [+ source [/A | /B] [+ ...]] [destination [/A | /B]]

    [skipped]

    To append files, specify a single file for destination, but multiple files
    for source (using wildcards or file1+file2+file3 format).

Try to concatenate 1000 files with natural sorting names using `copy`. I did this regularly and I have to write a python script it make it easier.

It's much easier to just right click any of the zip part files and let 7-zip to unzip it, and it will tell me if any part is missing or corrupt.

Why would you use manual tools to achieve what ZIP archive can give you out of the box? E.g. if you do this manually you’d need to worry about file checksum to ensure you put it together correctly.

Because, as said before, zip managing splits ends with two sources of truth in the file format that can differ while the whole file still being valid

Reply on news.ycombinator.com