subopen (was: What kinds of things would you want in the GNU OS?)

[gwyn at BRL.MIL]

In article <1989Jun5.112231.21303 at light.uucp>, bvs at light.uucp (Bakul Shah) writes:
>It is equally easy (and less magical) to let each process inherit the
>handles it needs.

This is inherent in the use of kernel data pointers.  The real trick is
how to communicate handles between processes (across "exec", etc.).  We
need suitable IPC anyway, which should be able to provide what's needed.
The UNIX approach of having the kernel maintain file tables for processes,
indexed by small integers, doesn't seem to generalize well; one needs to
know which small integers mean what when a process begins.

>You may say the kernel already maintains u_cdir (cwd) and u_rdir (root)
>inode ptrs so what is the big deal.  My point is that we don't need them
>so why keep them.

Exactly!  However, there is a need for a "virgin" process to acquire its
first handle so it can get others.  Inheritance is useful but incomplete.

>IMO kernel maintained variables are even worse than global variables.

Yes, yes.