[TUHS] Fwd: Choice of Unix for 11/03 and 11/23+ Systems

[Pete Turnbull]

On 27/09/2020 22:12, Warner Losh wrote:

> Maybe a bit of electrical tape over the fingers on the 256KB board would 
> keep them isolated from these signals? That would help determine if it 
> is just floating pins, or that the LSI-11 used these pins for other reasons?

No need for tape or any other test.  The pin assignments for both the 
original LSI11 bus, as used in the 11/03, and the Q22 bus used in later 
machines, are well documented.  The 16-bit pinouts are listed in the 
1976 edition of the Microcomputer Handbook, the 18-bit in the 1980 
edition, and there's a comparison table with Q22 in the 1982 
Microcomuters and Memories handbook.  There are more differences than 
the BDAL18-21 lines and there are even differences between the KD11-F 
and KD11-HA.

The SRUNL signal that was mentioned isn't likely to cause a problem; 
it's on both AF1 and AH1 in an 11/23 and a KD11-HA, but only on AF1 on a 
KD11-F, and I'm not sure it's bussed anyway in most backplanes.

BDAL18L is on BC1, and that's an internal clock signal on a KD11-HA. 
BDAL19-21 are on BD1-BF1 and they're connected to MICROM signals in the 
KD11-HA.  None of them are connected to anything on a KD11-F.

-- 
Pete
Pete Turnbull