Technical Linux questions

[jc at trillian.mit.edu (John Chambers)]

Derek D. Martin writes:
| I think in general, the more threads look like processes, the less
| complex the kernel gets, but the less efficient thread switching
| becomes.  Like everything else, it's a tradeoff.

Which reminds me of  a  question  I've  never  really  seen
answered:   How  exactly  do kernel threads differ from the
result of a vfork() call?

If a kernel thread gets its own pid, and shares memory with
the  parent, that's exactly what vfork() did in the systems
that had it.  Is "kernel thread" just a fancy new name  for
an old idea?

(One difference seems to be that documentation  on  threads
is  a  lot more confused and ambiguous, making it difficult
to determine exactly how they behave.  ;-)