Is it better to use threads or fork in the following case

[CTO]

Probably better just to check HEAD and see if its updated within the
time you're
looking at before any unpack. Even on a 56k that's going to be pretty
fast, and
you don't risk unpacking an old file while a new version is on the
way.

If you still want to be able to unpack the old file if there's an
update then
you're probably right about needing to run it concurrently, and
personally I'd
just fork it for ease of use- it doesn't sound like you're trying to
run 100,000
of these at the same time, and you're saving the file anyway.

Geremy Condra