[Info-vax] Reloading device drivers on x86-64 VMS

[VAXman- at SendSpamHere.ORG]

In article <mdj06e$lds$1 at dont-email.me>, "Craig A. Berry" <craigberry at nospam.mac.com> writes:
>On 3/8/15 8:38 PM, David Froble wrote:
>
>> If you want to install a new version of a sharable image, if it's
>> compatible with the old version, what does it matter how long before the
>> old version isn't used?  If it isn't compatible, I think you got more to
>> worry about than replacing a sharable image.
>
>I never said anything about loading a new version. The word was "unload"
>and in a subsequent post I referenced "a dlclose() or equivalent that
>actually frees up resources," which, despite the reference provided,
>seems not to have gotten the point across.
>
>Let me try again with an example. A modern web framework might have some
>dozens of modules or classes or extensions or plug-ins or assemblies or
>whatever the loadable pieces are called in your language of choice, and
>each might involve loading one or two or ten shareable images (or more,
>given the long dependency chains). A web server process might load up
>one set of these things to satisfy one request, but then need to load an
>entirely different set to satisfy the next request within the same
>process and main image activation, so you end up with all of the
>resources required by both sets allocated at the same time. Under some
>(but not all) circumstances, it might be desirable to be able to unload
>one set before loading another, basically undoing everything that was
>done by LIB$FIND_IMAGE_SYMBOL.
>
>Which, as hb said, the VMS image activator cannot do. Which I knew,
>which is why I said it might be a nice feature to add, given that other
>OS's, such as Linux, already have it (the latter of which I didn't say
>previously, but seemed obvious in context).

So, what is wanted is a SYS$IMGDACT in conjunction with SYS$IMGACT?  

FWIW, I've done this sort of thing in the past with some kernel mode
hackery.  Delete the VAs of the activated image, dequeue its I(M)CB,
and some other general mopping up.
-- 
VAXman- A Bored Certified VMS Kernel Mode Hacker    VAXman(at)TMESIS(dot)ORG

I speak to machines with the voice of humanity.