7 Sep
2016
7 Sep
'16
5:31 p.m.
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
Pete Turnbull