>I have no experience with any BSD, am trying to decide if I can install NetBSD
>on present computer or new computer I am shopping for.  I have experience with
>Linux, and believe tar, or at least its main functions, behaves about the same
>across all Unixes.

Might this (using z flag with tar) be true for noncommercial Unixes?  Now I
recall the commercial Unixes used compress instead of gzip, and compress was not
available for open source.  So the commercial Unixes didn't have gzip, at least
not as part of the commercial package, though commercial Unix users are free to
download open-source software.  Open-source Unix clones couldn't use the
closed-source compress and vi, had to develop gzip and elvis (and other enhanced
vi clones).

>Actually, in Solaris and IRIX you can't use the -z flag, so you have to 
>gunzip first and then use -tar -xvf.  I guess it's the same for other Unixes.

I presume (Free, Net, Open)BSD use the open-source gzip and tar, and tar
recognizes -z flag?