PDP-11/23 Debugging

Ben Sinclair bensinc at gmail.com
Tue Nov 18 13:49:12 CST 2014

Hi John, the O vs. 0 was just me copy and pasting from what was probably an
OCR'd copy of the XXDP manual.

Mine does have a MMU (which tests fine), but does not have a FPP. XXDP has
separate diagnostics for the FPP, and the docs say that it expects to have
passed JKDBD0 first, so I was assuming JKDBD0 doesn't do any FPP tests.

But, I think you might be correct on that I just don't have something setup
that the CPU test wants. The "refer to your microfiche library" line is a
bit daunting! Bitsavers does have some of the microfiche scanned, but I
can't make enough sense of what's out there to even find the right one.

There seems to be very little real info about the XXDP tests, and I don't
think anyone even remembers what XXDP stands for!

Since everything else seems to work, I'm going to get back to trying to get
my RL02 to run. If you haven't had enough of me already, get ready for RL02

On Tue, Nov 18, 2014 at 1:40 PM, John Wallace <johnwallace4 at yahoo.co.uk>

> Apologies if this is obvious/already covered, but along the same lines as
> Noel's
> "it's probably 'JKDBD0', not "JKDBDO"
> it's almost certainly
> not
> Of itself, that may not matter much.
> However, it may lead elsewhere.
> The F11 was [obviously] the 11/23 (and /24) chipset.
> Perhaps not so obviously,11/23 boards were available in variants with or
> without floating point, and (iirc) with or without memory management unit
> (MMU) (correction welcome). Also, the relevant bits were socketed, hence a
> particular board today may not match the board (and part number) as
> originally manufactured. Relevant handbooks etc will contain further
> details.
> I can't remember what's been previously written in this thread, but is it
> vaguely conceivable that the diagnostic
> in question needs a piece of hardware that isn't on the board in question,
> or is seriously broken on the board in question?
> A search for DCF11-AA CPU Diagnostic gets a few hits, including
> http://www.pdp-11.nl/pdp11-24/cpu/diags/jkdb.html
> which contains the delightful line "For more infromation refer to your
> microfiche library." and some rather more useful stuff too - sounds like
> you've found this or an equivalent already?
> Hope this helps, best of luck.
> John Wallace

Ben Sinclair
ben at bensinclair.com

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