PDP-11/05 (was: PDP-11/05 microcode dump?)

[Tom Uban]

Thanks Bill, nice read. Did you get your RK11/RK05 up and running on the 11/05?
My 11/05s both have the low profile side mounted chassis, which I find makes them nice and compact,
but limits their expansion without another cabinet.

--tom

On 6/13/21 3:59 PM, Bill Degnan wrote:
> It's no gunkies but I wrote up a few notes about my 11/05 variants and support issues here:
>  https://www.vintagecomputer.net/digital/ <https://www.vintagecomputer.net/digital/>.
>
> Bill
>
> On Sun, Jun 13, 2021, 4:44 PM Tom Uban via cctalk <cctalk at classiccmp.org
> <mailto:cctalk at classiccmp.org>> wrote:
>
>     I am working on the first of my two 11/05s. Interestingly, it has the early version M7261E Control
>     Logic & Microprogram board and the later version M7260 Data Paths board (with circular baud rate
>     selector switch) as described in:
>
>     http://gunkies.org/wiki/KD11-B_CPU <http://gunkies.org/wiki/KD11-B_CPU>
>
>     >From the description there, it seems like an older/newer combination, but maybe that was
>     common. I
>     would not have guessed that the four possible combinations would all work together, but maybe
>     they do?
>
>     I have a couple different drawing sets for the 11/05 and while some have the matching M7260
>     schematic, only the GT40 drawings (I found on bitsavers) has the M7261E schematic:
>
>     http://www.bitsavers.org/pdf/dec/graphics/VT11/GT40_Graphic_Terminal_Engineering_Drawings_Feb73.pdf
>     <http://www.bitsavers.org/pdf/dec/graphics/VT11/GT40_Graphic_Terminal_Engineering_Drawings_Feb73.pdf>
>
>     The GT40 drawings has the PROM listings and related, so I am hoping that they match what is in the
>     two boards.
>
>     Presently, the machine sometimes runs relatively well and other times it does not. It does
>     have bit
>     1 stuck ON in memory, but that should be a relatively simple task to diagnose as it is not
>     intermittent. When the machine is "working" I am able to deposit 0777 at 0100 and run. When
>     running
>     this simple program, I've experimented with flexing the boards and such, so it doesn't seem
>     like an
>     obvious poor connection, but that remains to be seen.
>
>     The machine is a configuration #2 model (as described in the "gunkies" site) and my initial
>     messing
>     with KM11 boards, reveals that I can step the microcode with a KM11 in either the #1 or #2
>     position,
>     but when two KM11s are installed at the same time, they do not function properly together. Is this
>     expected or do I have an issue there too?
>
>     Thanks much to those who have provided details and documents on the web, they have already been of
>     great value and will most certainly continue to be a resource in the future.
>
>     More updates in the future...
>
>     --tom
>
>     On 5/6/16 5:32 PM, Noel Chiappa wrote:
>     >     > From: Mattis Lind
>     >
>     >     > Thanks Noel for sorting this out.
>     >
>     > Eh, de nada. But thank you.
>     >
>     >
>     >     >> I wonder if the ucode in the two versions is identical? The uROM chip
>     >     >> numbers should give it, (if they are the same on both versions, albeit
>     >     >> in different locations on the board), but I have yet to check. Does
>     >     >> anyone happen to know?
>     >
>     > OK, so the situation here is pretty complicated. To start with / make things
>     > worse, that CPU uses lots of PROMs. Lots and lots and lots and lots of PROMs.
>     >
>     > For the data paths board (M7260), both major versions appear to contain the
>     > same PROMs (going by the DEC part numbers), but the chip location (Exx)
>     > numbers are all different.
>     >
>     > For the control board (M7261), the C, E ('early' version) and F ('late'
>     > version) etch revisions each contain mostly the same PROMs, but apparently
>     > with slight differences between the sets of PROMs in each (as reflected in
>     > different DEC part numbers). For details see:
>     >
>     >   http://gunkies.org/wiki/PDP-11/05#Control_PROMs
>     <http://gunkies.org/wiki/PDP-11/05#Control_PROMs>
>     >
>     > to which I have just added all the gory details.
>     >
>     > As to getting the contents of all of them dumped in machine-readable form -
>     > oi vey!
>     >
>     >
>     >     >> on the earlier version (prints for that version are in the GT40 prints
>     >     >> online
>     >
>     > It turns out that I have hard-copy prints for the "C" etch revision of the
>     > M7261, which do not yet appear to be online; the GT40 prints have the "E"
>     > etch revision.
>     >
>     > I will scan the pages for that revision of the board, and put them up 'soon'.
>     > (I'm not doing the whole print set, it's about 1" thick, and most of them are
>     > for other things anyway, like MM11-L memory, etc.)
>     >
>     >       Noel
>     >
>