ZIP plugin ver 1.30

[Ainvar]

Trying to zip up alot of my e-books to save some space and was looking at trying to set the compression to maximum compression. Was not able to do and I was curious as to ask if these zips are pc compatible also.

Is there a future feature as to what compression I want to use or is there one compression fits all?

[sponge]

The zips should work on PC too, unless Dan coded a new compression algorhytm, but I'd be surprised.

[James S]

No, their general zip files. If they weren't zip files then they'd be named dez files or something, because ZIP is a set of patented compression algorithms. If you want to save some more space try compressing them using gz instead of zip. gz has a much better compression ratio, but aren't as versatile as zips, although that won't matter since you're just zipping up regular old text files, which gz is GREAT for.

[sponge]

If they're plain text files, you won't see a substantial difference either way.

[Dan East]

The Zip files created by DEXplor are true Zip files and are compatible with other software (winzip, pkzip, etc).

I defaulted to maximum compression and did not provide an option to use a lesser compression. I will probably add that capability in the future because it will be pretty easy to implement, although most people will still use max compression.

Moose, Zip uses zlib compression. Think of a zip file as a conglomeration of gzipped files with additional file attribute info (like the path, modified date, time, etc). So you will see the exact same compression between zip and gzip when using the same compression level. Of course there is a small amount of additional overhead in a zip because of the extra info per-file it stores, but it is a small amount, and is not dependant on the size of the original files.

Dan East

[Ainvar]

Thanks for the info, I was thinking that but since my cradle is at home and no way to test some of it, I thought it would be easy to ask here.

Thanks for the info on how you did both the gzip and zip stuff on DEXplor. The ebooks compressed shaved off about 200k per file so I save about 12 megs in total when I was done making individual gzip files. when I did do the new zip file I only saved maybe have that space (prolly more but I was guesstimating). Plus this makes it to where I can store more books on this 128meg sd card until I can get a 256 or the 512 comes down enough to justify the purchase.

[James S]

Well, I learned something today. I knew that ZIP had all that special stuff, but I thought they were entirely different formats, of sorts.

[Dan East]

I'll add one more thing. If you are storing files directly on your Pocket PC then the OS will compress the files using a fast, low quality algorithm. To give you a rough estimate with text files, the OS compressed them to around 50% of their original size, while zip / gzip compressed them to 25% of their original size. So compressing files that are going to be stored directly on the device does not save you as much space as it would appear going by the filesize alone, although it does help some.

Now in your case you gain all the file space you reported because the OS does not automatically compress files on a Storage Card.

Dan East