1. I thought that "zlib" library can handle compress data, because I use command "gzip -d filename.Z" to uncompress it, and it works.
May be I am wrong and "zlib" do not handle it, then which one handles it?

Now I looked into gzip sources from http://ftp.gnu.org/gnu/gzip/ and it appears that "gzip" uncompresses .Z data using its own algorithm without zlib.
I think using proper file from there will be more portable, but this is not easy way, of course.

2. Please excuse me for being unclear.
I meant following behaviour. When my perl program eats big ammount of memory, it does so in non-linear way.
When I see in task manager how much memory system allocated to processes, I see it like a stair, where first step is small, second step is twice bigger, next step of that stair is two times bigger than previous.
When I saw that perl already got 256M, I expect it will take 512M next time, and usually at this time I decide whether to allow it to run...
I remember this was discussed a little on p5p recently, but no special decision was made.

Courage, the Cowardly Dog