DecServer 550 chassis

Johnny Billquist bqt at
Mon Oct 19 14:39:33 CDT 2015

Well, you did ask for "thoughts in the conversion", so I gave you mine. 
Sorry if you felt they were unhelpful. I just thought the "conversion" 
was basically a no-work. Programming proms is something I have spent 
more time than I can count on, and is so routine that I don't even think 
about it.


On 2015-10-19 20:57, jwsmobile wrote:
> On 10/19/2015 10:03 AM, Johnny Billquist wrote:
>> Not sure what you expect a "conversion" means. Creating new PROMs
>> imply finding actual proms, a prom programmer, the code to program
>> into the PROMs, and then just replace the proms on the card.
>> Only the last piece will actually require any modification of the
>> card, and I would expect them to be socketed anyway, so replacing
>> means just removing the old proms, and inserting the new ones.
> That is basically what I said.  I don't have one that isn't part of a
> DecServer and i need images, or someone with a non DecServer to provide
> them.
> I guess you restated what I said.  if you have one, I'd appreciate copies.
> I didn't post the original link from the top of this thread, you might
> want to read it.  I'm just stating what someone did back in the 2001
> time frame and posted a page about the conversion and info on his
> experiences.
>> The note also mentioned that you might want/need to install a pull-up.
>> But it would still be an extremely simple process. You just need the
>> right bits...
> What I said.
>>     Johnny
>> On 2015-10-19 18:28, jwsmobile wrote:
>>> I would appreciate thoughts on the conversion of the processor to normal
>>> PDP11 eproms.
>>> The page pointed to earlier has a mention of that too, but the poster
>>> had access to another "real" KDJ and I am guessing copied that.
>>> I don't have access to any version of the system with appropriate eproms
>>> and would appreciate any pointers to the binaries needed.
>>> As to the condition most of the material is the result of moving it from
>>> where it was stored.  It will be totally disassembled and tested before
>>> being brought back up.  There is about 5 or 6 large deep freeze (for
>>> reference) sized piles of material being sent for e-waste from the place
>>> that is pretty much just junk material under the weather.
>>> Think of this as a Dusenberg rescued from a barn though.
>>> thanks for all the suggestions and observations.
>>> Next thing to go over is a Sun 4/260 "mini" tower.  Gads those were
>>> heavy.  Back is still aching from moving that.
>>> Jim
>>> On 10/19/2015 7:32 AM, Ethan Dicks wrote:
>>>> On Mon, Oct 19, 2015 at 3:42 AM, Pontus Pihlgren <pontus at>
>>>> wrote:
>>>>> Interesting. I thought Tthe DECserver 550 was merely the big
>>>>> brother in
>>>>> the terminal server line. But it looks like it is essentially a
>>>>> PDP-11/53 with 1.5MW of ram, you need new boot roms though. Pretty
>>>>> nice.
>>>> Yep.  It's essentially an S-box KDJ11 with different ROMs.  I happen
>>>> to have a CPU board from one, but not the box itself.
>>>> One of these days, I plan to burn "real" PDP-11 ROMs and bring 2.11BSD
>>>> up on mine.  That and my Pro380 are my only KDJ11 machines.
>>>> -ethan

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