DecServer 550 chassis

Holm Tiffe holm at
Tue Oct 20 02:38:14 CDT 2015

Johnny Billquist wrote:

> On 2015-10-19 23:11, jwsmobile wrote:
> >
> >
> >On 10/19/2015 12:39 PM, Johnny Billquist wrote:
> >>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.
> >>
> >I didn't mean that in disrespect.  The contents of what I posted was on
> >the page and I basically needed the binaries and needed some direction
> >as to which went where.  I appreciate you taking time to reply, but am
> >coming from a lot less capability than you have.  I do a lot of
> >computing and the like, but I've purposely not kept up with eprom
> >technology to the point that i can't reliably swear I can program them
> >right now.
> >
> >There are only so many things one can keep up with and eproms were not
> >one that was cheap to follow, and I was more into EE type devices anyway.
> Well, EPROMs are getting sortof old fashioned nowadays.
> >I may need a favor by swapping you some of my eproms (I have a 12" x 12"
> >x 12" box of pulls) maybe to get you to make me a set for my board.
> Unfortunately all of my stuff in Sweden, while I nowadays live in 
> Switzerland. So I could only possibly help out next summer.
> But I probably would have some 27256 around.
> >I've pulled out probably 500 and returned them to the original owner and
> >owe him more.  but I do probably have a lot of the 27xx proms.
> >
> >Do you think these are 27C or just straight 27 type eproms, and if so
> >what speeds?  That is what I need to know too.
> I normally don't care about that. The difference is in how you program 
> them, and there are more variations than that. Fortunately my programmer 
> knows a whole bunch of them, and also can autodetect the different models.
> But once they are programmed, the actual pins are the same, so speed is 
> the only possible issue. But I think most of them are 125ns, which is 
> fast enough anyway.
> I replaced the firmware in some 11/93 boards a few years ago. But I 
> think I just reused the existing proms that time.
> But I don't have any 11/53 boards, so I can't do that here.
> 	Johnny

I can do a look later this day. I've done exatly this some years before,
and the KDJ11 that is working now as plain CPU isn't in a machine
currently so I have it handy.

As far as I remember I've used 27C256 Proms and the contents of the
previous ones are on Pete's archive since they where newer then the 
images he had.
I've updated the memory from 512K to 1,5Mb too...


      Technik Service u. Handel Tiffe,, Holm Tiffe, 
     Freiberger Straße 42, 09600 Oberschöna, USt-Id: DE253710583, info at, Fax +49 3731 74200, Mobil: 0172 8790 741

More information about the cctalk mailing list