2 Aug
2021
2 Aug
'21
8:58 p.m.
On Sun, Aug 01, 2021 at 10:42:53PM -0400, Douglas McIlroy wrote:
It's certainly clear that some kind of primitive is needed to create
new threads. An open question is whether if there exists some kind of
"new thread" primitve plus either spawn(2) or some kind of "create a
child process and then then frob like crazy using 'echo XXX >
/proc/<pid>/<magic files>'" whether there still is a need for a
fork(2) system call.
Obviously, as soon as we start going down this path, we're deviated
quite strongly from the "radical simplicity" of Unix Version 7 that
people have accused modern systems (whether they be Linux or FreeBSD)
of lacking. It's rather interesting that we haven't heard complaints
about how people who dare to try come up with new API's are somehow
traitors to "The Unix Philosphy" that we've seen on other threads. :-)
- Ted
spawn() beats
fork()[;] fork() should be deprecated
Spawn is a further complication of exec, which tells what signals and
file descriptors to inherit in addition to what arguments and
environment variables to pass.
Fork has a place. For example, Program 1 in
www.cs.dartmouth.edu/~doug/sieve/sieve.pdf forks like crazy and never
execs. To use spawn, the program would have to be split in three (or
be passed a switch setting).
While you may dismiss Program 1 as merely a neat demo, the same idea
applies in parallelizing code for use in a multiprocessor world.