M9301-YB Bootstrap/Terminator ROM dumps / listings?

Josh Dersch derschjo at gmail.com
Wed Apr 29 23:13:14 CDT 2015

On 4/29/15 5:14 PM, Don North wrote:
> On 4/29/2015 4:11 PM, Josh Dersch wrote:
>> On Wed, Apr 29, 2015 at 3:58 PM, Noel Chiappa <jnc at mercury.lcs.mit.edu>
>> wrote:
>>>      > From: Jorg Hoppe
>>>      > I also have a spare DL11-W to offer
>>> Josh, if you want a second serial line, it's best to use a regular DL11
>>> (M7800), not a DL11-W. (M7800s are available on eBay, for pretty modest
>>> amounts.) The reason is that each DL11-W presents a load on the line 
>>> clock
>>> signal (from the power supply), even if the line clock on the second 
>>> board
>>> is
>>> disabled; several Dl11-W's, and the line clock signal may get 
>>> overloaded.
>> That's good to know, thanks.  I do have a spare DL11 in my stash of 
>> spare
>> boards, I just need to find it, it appears to have gotten misplaced 
>> during
>> my house move last year.  Not sure if it's a -W or not.
> I've had two DL11-W in my 11/34A BA11-K box for years and have never 
> had an LTC issue.
> I suppose if you had a a larger number (say four or more) you might 
> possibly see an LTC
> issue, but I never have with just two. In any event you could 
> completely disconnect the
> LTC circuitry on the DL11-W by removing just one inline series resistor.

Here's the official word, straight from the 11/34 user's manual on 
Bitsavers (Page 4-20):

In boxes other than the BA11-L, there is not sufficient drive capability 
on the LTC L signal to
drive multiple loads.  Since each DL11-W constitutes a load (even if the 
line clock is disabled
by the switch), multiple DLL11-Ws in a box will overload the LTC L 
signal causing line clock failures.
To alleviate the loading effect of the additional DL11-Ws, remove the 
resistor R64 from all DL11-W
modules except the one being used as line clock.  If multiple DL11-Ws 
are used on the same system,
the line clock must be enabled (via switches) only on thee DL11-W being 
used as a line clock."

I found my spare SLU, and it's a DL11-W, and I have a BA11-K.  I'll see 
if I run into issues, and if so I'll pull the resistor

>>>      > From: Josh Dersch
>>>      > I need to scare up a second SLU so I can get an emulated 
>>> TU-58 hooked
>>>      > up to try booting XXDP
>>> I'm not sure any M9301 variant supports the TU-58? Some are set up 
>>> to boot
>>> over the console serial line, though. (I haven't yet checked the 
>>> code, so I
>>> don't know whether you need to feed it the absolute loader first, or 
>>> if it
>>> will just take .LDA files directly.)
>> I'm now running off of a M9312, and there is a TU-58 boot PROM for that
>> (see here: http://ak6dn.dyndns.org/PDP-11/M9312/).  I believe I have 
>> a set
>> of compatible PROMs and I'll probably try that tonight, if I can find 
>> the
>> time (and the DL11 :)).
> The 'ZZ' (my notation) for the M9312 is also a useful addition for 
> debug/sanity checking.
> It goes in like a device prom, but just runs the simple M9312 console 
> diagnostics and low
> memory (28KW or less) memory test continuously. Image available on the 
> link to my website
> above, or contact me directly and I can provide a preprogrammed 
> device. Same for the TU58
> (or other) boot proms.
Cool, thanks!  I'll let you know if I have need of your services :).

- Josh

> Don

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