More mystery recycler boards - DEC, Fujitsu(??), Cipher, Emulex

Pete Turnbull pete at
Wed Sep 7 17:59:29 CDT 2016

On 07/09/2016 22:35, Noel Chiappa wrote:
>     > From: Pete Turnbull
>     > Don't forget the LTC :-)
> ?? The KDJ11-A has an on-board LTC - see EK-KDJ1A-UG-001, pg. 1-7.

So it does.  I'd forgotten that!

>     > Otherwise, you'd need an additional bootstrap card such as an MRV11-D
>     > with -B2 boot ROMs, a DLVE1 (DLV11-JE) for the SLUs, something with an
>     > LTC, and termination.
> Err, the KDJ11-A has on-board termination: see MP-01890 pg. 1 of 9, on the LHS.

I meant for the other end of the bus.

>     > A BDV11 wouldn't work as it doesn't have the ROM capability
> ?? The BDV11 is a ROM board?
> (And it works fine in a Q22 bus; the address recognition circuitry uses BBS7,
> it doesn't look at BDAL 16 and above.)

Yes, it has a lot of ROM sockets: it's a bootstrap/terminator/LTC card. 
In fact it's the archetypal bootstrap card, the one that first had the 
paging mechanisms all the others use.  The problem is none of the 
sockets support large ROMs, so there's a lot of fiddling to do to get a 
microPDP-11 bootstrap and diagnostics in there.  You have to split each 
ROM into four devices, so eight in total.  I'm well aware of how BBS7 
works, but that's not the issue.  Unless the BDV11 is modified, it 
doesn't work correctly in a 22-bit system as it has 18-bit termination. 
Although DEC listed the BDV11 (Rev.F only) as compatible they classed 
22-bit 11/73 systems using a BDV11 of any sort as "not field 
serviceable" and wouldn't supply or support any that way.

Pete Turnbull

More information about the cctalk mailing list