Kernel mods and RTIngres

[Doug Gwyn <gwyn>]

> > For example, one can write per-system-type user-mode "lock"
> > interface modules that work acceptably well.
> 
> Really, how does one write such wonderful beasties? Indeed, what
> do you mean? You have lots of buzz words, but you didn't say anything.

This is such a standard technique for portable packages that I didn't
think anyone would fail to understand (but then obviously RTI doesn't
or we wouldn't be having this conversation).  To make it clearer,
consider that the application code is written once, in a system-
independent manner, and that all access to any host features that are
not fully standardized (e.g. beyond stdio, strcpy, etc.) is done by
means of a separate support library.  The interface to the routines in
the support library is carefully designed to be achievable on a wide
variety of systems.  For each target system, there is an implementation
of the support library whose internal details are system-specific, but
whose interface used by the application is invariant across all systems.

Now, I'm not going to design a portable interface to file/record
locking facilities for you; that's the job of the software engineering
(what's that?) department.  Get to work!

> > Not only that, but when RTI made our Ingres users install their
> > lock driver, it turned out that their software still didn't
> > support concurrent database updates!  What was the point of the
> > lock driver??
> 
> The point of the lock driver is to keep two people from updating
> the same relation at the same time. ...

Good grief, I just explained that RTI Ingres FAILED to do this right
in spite of their "lock driver".