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

Pete Turnbull pete at
Wed Sep 7 19:31:16 CDT 2016

On 08/09/2016 00:37, Glen Slick wrote:

> 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.

Too big.  They're a pair of 8K ROMs, but the BDV11 only supports 2K and 
1K devices.

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

I guess that's the reason.  I've only ever seen two, but I've seen (in 
fact I have) lots more earlier ROM boards and several MXV11-Bs.  I 
suppose by the time the MRV11-D came out, people who needed a bootstrap 
paging capability either had 11/03 or 11/23 systems with BDV11s or, if 
they needed an 8K bootstrap, had microPDP-11s, in which the bootstrap is 
always on the CPU card.  Almost anything else could use the cheaper 
MRV11-C (though it only supports up to 4K chips) and even that supports 
the conventional bootstrap mechanism, albeit only 16- or 18-bit, not 
using BBS7.

Pete Turnbull

More information about the cctalk mailing list