DEC 11/23 FP option (FPF11/M8188) information request

From: Eric Smith <>
Date: Wed Oct 8 16:12:15 2003

Patrick Finnegan wrote:
> I've managed to pick up an FPF11/M8188 (PDP-11/23 Floating Point option)
> for my PDP-11/23, [...] I've got a non-+ 11/23 CPU board that I'd like
> to get it to work with,

"emanuel stiebler" <> wrote:
> I hope I understand you here, but if you're trying to use it on a non
> 11/23 system you out of luck (OK, you can use it on a 11/24 too ...)

I think Patrick meant that he wants to use it on an 11/23 that is
not an 11/23+. The former uses the KDF11-A dual-height CPU (M8186),
and the latter uses the KDF11-B quad-height CPU (M8189).

I think the FPF11 should work with either, but I'm not 100% certain.
You need a cable from the 40-pin header on the FPF11 to one of the
MICROM sockets on the KDF11. I'm not sure whether it makes any
difference which MICROM socket is used.

For example, the KUV11 WCS option (M8018) for the LSI-11 (11/03, KD11-F,
M7264) needs a particular MICROM socket with an extra signal, and so it
won't work on the double-height LSI-11/2 CPU (KD11-HA, M7270) which
does not have that signal wired to a MICROM socket. I don't know whether
the FPF11 has similar considerations.
Received on Wed Oct 08 2003 - 16:12:15 BST

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