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

Glen Slick glen.slick at
Wed Sep 7 18:37:39 CDT 2016

On Wed, Sep 7, 2016 at 3:59 PM, Pete Turnbull <pete at> wrote:
> 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.
uNOTE #004
LSI-11/73 Upgrade Paths

1. In the following upgrade scenarios, the systems have been labeled
as being Field Serviceable or not. A system which is Field Serviceable
has a bootstrap which meets Field Service requirements. The
requirement is that the bootstrap must execute an 11/73 cache memory
diagnostic on power-up. There is not guarantee that the overall system
will be Field Serviceable or that it will be FCC compliant."

Basically this boils down to having the MXV11-B2 Boot ROMs installed
on either an MXV11-B or MRV11-D. The MXV11-B2 Boot ROMs are apparently
not compatible with the BDV11, for reasons I don't remember 100% off
the top of my head.

Why are MRV11-D boards so expensive, at least on eBay? Were they sold
in relatively low volume compared to CPU boards?

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