zip (was: Re: Disk archival techniques)

[Jules Richardson]

On Tue, 2005-05-17 at 15:20 -0700, Dwight K. Elvey wrote:
> >From: "Brian Wheeler" <bdwheele at indiana.edu>
> >
> ---snip---
> >
> >I think the optimum format for doing this isn't a single file, but a
> >collection of files bundled into a single package.  Someone mentioned
> >tar, I think, and zip would work just as well.  The container could
> 
> Hi
>  tar yes, zip no!!!! Any form of compression will make recovery
> difficult if there is a small amount of data lost in the middle
> someplace.

I went through this on one of the Acorn newsgroups recently (habitually
I use tar over zip for just the reason you stated).

Someone pointed out that zip is capable of a 'no compression' format and
acting as a pure archive. I did a few tests trying to mangle such an
archive with a hex editor, and indeed (at least on Linux) the zip
decompression util was able to restore past the damaged part of the
archive and detect the corrupt data.

So, question is, are zips with no compression portable? It certainly
seems that DOS, Linux, and Acorn systems can handle them. No idea about
Winzip or other flavours though.

If it *is* portable, it might seem a better choice for archives over
tar, simply because more systems these days can handle zip files than
can handle tar files...

cheers

Jules