M9301-YB Bootstrap/Terminator ROM dumps / listings?

Johnny Billquist bqt at update.uu.se
Thu Apr 30 19:26:08 CDT 2015

On 2015-04-30 21:18, Don North wrote:
> On 4/30/2015 9:55 AM, Johnny Billquist wrote:
>> The per-device code are in separate PROMs that are used in both the
>> 9301 and 9312. Those are the ones with the device code as constants in
>> the beginning of memory space for the PROM, by the way. (I seem to
>> remember someone mentioning this in the past.)
>>     Johnny
> The M9312 device boot proms are totally different format and structure
> than the M9301 proms. Not interchangeable.

Hm.. I could have sworn they were the same. Oh well. Figures. :-)

> The M9301 has four 4b wide proms configured as a 512x16 and the console
> and device boot code all live in this address space.

That is also true of the M9301.

> The M9312 (and the 11/44 also) have one 4b console PROM, and four slots
> for 4b wide device boot PROMs. Each of the PROMs are nibble accessed to
> build a 16b word from four 4b nibbles. The PROMs are all independent of
> one another.

Yes. And this is more or less also how it works on the M9301. However, 
it seems that DEC didn't actually put difference devices in their own 
roms for the M9301, but treated the whole ROM memory as a big chunk with 
a bunch of different devices bootstraps in there.

I thought I remembered moving boot roms from an M9301 to an M9312, but 
that must be my memory playing tricks with me then.

> The 11/44 module has its own console boot code PROM, but it uses the
> standard M9312 device boot PROMs.

Yes. As do the 11/84 and 11/94, which can take those boot roms in the 
Unibus adapter.

> For the M9312, there are two console PROM variations, one for the
> 11/04/34/etc class machines, and one for the 11/60/70.



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