winzip + disk cleanup?

ok, so i got a little problem or rather a worry :

i had 352mb of free space and a zip file of 470+mb on the same hdd.
as i didnt need some of the files in that zip, i deleted them (around 50mb).
i did so directly out of winzip 10, which actually makes a new file out of the old
but without the selected (deleted) files. i must mention here that the compress-ratio
of those files was 0% (that is, from my 470mb file in the beginning i would get a 420mb file).

as winzip makes a new temp file before deleting the old zip, its clearly that the temporary
420mb file couldnt fit on my 352mb free space.
and there's my worry.
it went all thru. win xp showed some warning (several times) about you're memory is low, do a cleanup etc
but as winzip froze (for a while) i couldnt do anything fast enough (also it took me a while to figure out whats happening).

ok, so after a few min, winzip unfroze, the process was done, i got a new zip file of 420mb, all working fine
and the old one deleted, but also 465mb of free space (rather than the expected 352mb + ~50mb = ~ 400mb). so if i do the math, some 100mb of space was freed, but i deleted only 50mb.

here's my worry: where did those extra 50mb come from? or what was deleted???
i repeat: compress ratio was 0% and i didnt do any cleanup
did windows xp (or winzip) delete some files by its own? and how would i know which ones?

thanks in advance

When you create a Zip file it compresses the data into a smaller form. This is how large data files are sent so it doesn't take a half day to receive and render the file. However there is some data loss in this process which is negligible and 99.9% of the time it does not effect the file. For example a picture of 1.5 mb in data sent in a zip file is compressed to lets say .75 mb. Some of the data is lost in the compression but when viewed you cant see the difference until you start blowing it up and you can see pixels missing or distorted. Mind you, this is a simplified answer but gives you some idea of what is going on in zip files. This is how you recovered more space when you deleted some of those zip files. Just follow the process backwards and that's how you get more. Like I said this is an over simplified answer an the numbers in the example I just picked out but you should get the gist of it.

im sorry, but i think you misunderstood me.

the files were already zipped. i started winzip, selected some files
*within that archive file* and clicked delete *from the winzip menu*.
what winzip does next is to make a new temp file, compressing all the other
files *not selected for deleting*, and finally replacing the orginal archive file
with the temp one. that's how deleting FROM an archive file is done.
the files (some videos) i deleted had 0% compress ratio (which i stated several times)
which in other words means.... compressed or not those files take up the same space on the HDD,
so if i deleted them i couldnt have gotten double the space freed.

and that 50% gain you mentioned for images is only working for .bmp's coz jpegs and other formats
are already compressed.

so, i'd ask someone to answer my question from my original post..



Former Moderator
Hi! Maybe the extra space is un-related, do you use any high performance products ? Is there a lot of junk you can remove from your disc? Something like a mini dump happen recently?

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