[Info-vax] Crashing a system with PCA/DTM ?

[John Reagan]

On Sunday, August 26, 2018 at 12:08:26 PM UTC-4, Marc Van Dyck wrote:
> Now time for a weird question.
> 
> Long time ago, I developped some code that later on became an important
> component of our production environment. This was in Alpha times. So
> important that I implemented a regression testing environment with DTM
> and PCA, to ensure I didn't break anything with new versions.
> 
> This code was in fact quite stable so the regression environment was
> not used very often.
> 
> 10 years later we migrated to Itanium and I just rebuilt, without
> running the regression tests - all worked perfectly.
> 
> Now we migrated to VSI OpenVMS and my PCSI kit is broken, because it
> insists on having HP OpenVMS installed. At the same time, I finally got
> a request to implement a new function in my code (it's written in
> Pascal).
> 
> So I dusted off the development environment of this code, made some
> modifications, changed the PCF file to make a new kit for VSI, and
> rebuilt. So far, so good.
> 
> Now I'd like to run my regression testing again. It's painful enough to
> remember how DTM and PCA work, after having used it only once 15 years
> ago. But my problem is that when I did that 15 years ago, I crashed the
> development system. Twice. I'd like not to repeat that, but I do not
> remember exactly how it happened.
> 
> I tend to remember it has something to do with images installed, and
> possibly with privileges. My code is made of a shareable image,
> installed /OPEN /HEADER /SHARED, and a main image that calls it,
> installed with CMKRNL (it creates kernel mode logicals). Something
> about that being not compatible with PCA or DTM (more probably PCA).
> But the details escape me, it's too long ago.
> 
> Does that ring a bell to anyone ?
> 
> Thank you,
> 
> Marc.
> 
> -- 
> Marc Van Dyck

I don't remember that.  I've use PCA on a few things on Itanium in the past year or so and haven't crashed our development cluster, but not with installed images .  Are you doing performance work or just test system coverage?

Unless you are doing screen-based testing or DECwindows testing, DTM is pretty is just a bunch of tedious DCL command files.  PCA on the other hand, is a debugger and should use many of the same interfaces (including SSI for system service interception).  Perhaps there was an old bug with that?