zip folder of arbitrary size

[Ben Rubinstein]

I want an app running unattended on a Windows VM to zip up a folder (on a 
regular basis).

I've not used the revZip library before: when I look at it the first thing I 
notice is that first step, according to the Dictionary is:
	Use the revZipOpenArchive command to load a zip archive into memory

It's the "into memory" part that bothers me. The folder is probably around 125 
- 150MB in total; the zip file I'd expect to be 25MB. I know that we sometimes 
run into horrible memory problems on these Windows VMs, so this makes me nervous.

Does anyone have experience of working with this library on Windows, in 
relation to how much memory it uses?  I'm guessing the key formula is related 
to the size of the largest file to be zipped, and the size of the zip package 
itself.

My alternative is probably shelling out to Windows to have the folder zipped 
by an external process. Any tips in relation to this?

TIA,

Ben