[Info-vax] Apache + mod_php performance

[Lawrence D'Oliveiro]

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.