Re: Apache + mod_php performance

On Wed, 2 Oct 2024 19:05:31 -0400, Arne Vajhøj wrote:

The descriptor being moved is a kernel close thing on *nix, so for a
kernel reassigning is work but not crazy much work.
 
VMS is totally different. Especially for a file.
A file descriptor is pointing to some user mode C RTL data structures
that reference some RMS user mode data structures that reference some
RMS executive mode data structures that reference some VMS kernel mode
data structures.

If you leave RMS out of it, at the basic QIO level you have a channel,
which is an index into the CCB array, which is in per-process P1 space (or
whatever the 64-bit equivalent is). That in turn contains a reference to a
WCB in system space, which is how VMS kept track of an open file --
presumably there is some analogous structure for a comms socket etc.

So sharing those in-kernel structures is not the hard part -- it would be
easy enough to allocate a channel in the CCB array in another process and
have it point back to the same in-kernel structures.