Specific DEC diagnostic questions (FKTG & ZDLD)

"Jay West" <jwest at classiccmp.org> wrote: If you are capable of booting the machine to an OS, try doing things like assemblies of monitors, running TREK or ADVENT, or something that's actually enjoyable :-). RSX-11M+ has some damn good drive exercisers (IOX). Much more thorough than XXDP for walking washing-machine sized drives across the room! In RT-11, FMT will let you do bad block scans with various patterns. The DEC diagnostics were generally pretty good for doing what they do. There will be some corner cases where the machine will boot into XXDP or RT-11 but will have a fault that might show up in an application. I'm not going to claim that these corner cases never happen because over the years I've run across them a couple of times. But in most cases, a CPU fault or memory fault or drive fault will stop you from even being able to boot into XXDP. In a couple cases XXDP (because it generally doesn't use interrupts) will boot when the real OS's won't (and that itself is a really sharp finger pointing to something in the interrupt chain.) Third-party hardware (e.g. non-DEC drive controllers) will often work just fine in real life but not pass the XXDP diagnostics because XXDP is looking for some (undocumented) timing restriction that doesn't apply to the third-party stuff. Tim.