On Sep 24, 2014, at 2:32 PM, Earl Evans <earl at retrobits.com> wrote:
Hi there,
I have a floating point processor (FPP) on a currently unused 11/23 CPU
M8186 card (KDF-11A). From the manual, looks like this is a KEF11-A.
Also, in my working 11/23+ with KDF-11BA, I have no FPP. Makes it hard to
use Fortran-77. The KDF-11BA manual refers to a KEF-11AA FPP.
Does anyone know if the FPP unit is compatible from the 11/23 to the 11/23+
- i.e., can I transplant the FPP chip from the 11/23 to the 11/23+ CPU
card? Could it be that simple? :-)
Please be gentle if this is a stupid question. I've used my best Google-fu
and RTFMing to find the answer (and learned some new things about these
cards in the process).
No worries, not a stupid question. It should be possible; the F-11
processor extensions (FPP, CIS) are just microcode ROMs for the same
data/control/MMU chipset, so it should work nicely on your 11/23+
board. Make sure you have the MMU, though, because it uses the MMU
chip for the FP registers; I assume you have one, since I think the
11/23+ came with one by default.
There's a lot detailing the theory of operation for the KDF-11 CPU
in its manual, if you're interested. It's very nicely described.
- Dave