WTB: RX02 Floppy Disks

Ulrich Tagge u.tagge at gmx.de
Fri Aug 4 13:09:38 CDT 2017

Hi Jerry,
> You’ve made pretty good progress.
Yes with the right input and help this can happen. ;-)
And all the help is much appreciated!
> If you haven’t already, Google for and look at the manual for the SQ739. I think you will find that most of the
> commands for the on-board diagnostics are the same.  The unibus controller will have a
> different layout and perhaps a physical vector switch, but you should be able to sort out the differences.
Not done by now, but is now noted and on the plan for the weekend, I'm 
also interested to know about the jumper settings as there are some of them.
> What version of RT11 do you have?  The later versions would show the
> CSR that the hander is set to.
Its: RT-11SJ (S) V04.00I ... quite old.

> You mention a RC25.  Is that on another machine? If you have two MSCP
> controllers in the same backplane (KLESI? + SU723) then that is more complex.
> My guidance below assumes the SU723 and a bootable RX02 device are
> the only disks.  Do not follow if you have two MSCP controllers installed.
That's the right assumption, I have two /84 one with lesi and working 
RC25 where I have created the Floppy disks, and a playground mostly 
empty, but now equipped with SCSI and RX211.
> The address 160340 is not what is normally expected “standard” CSR for a MSCP.
> Its is easy to change the handler address.
> First make a copy of the DU.SYS handler to preserve it.
>             copy/sys du.sys duorg.sys
> The set the CSR that you are using
>             set du csr=160340
.SET DU CSR=17760340
?DU-W-Patch handler bootstrap, put CSR at 3264

> Try vector address 154 first, unless you know the board is configured differently.
> It appears already set for this, but here is how you change it.
>             set du vector=154

> You should then be able to install and load the handler.
>              install du
>              load du

> Depending on the DU handler, it is possible to map a large MSCP image to multiple
> partitions.  If the handler installs, try the following.  It show a basic mapping.
> Single controller, single drive and in this case 8 partitions.   The first partition
> should be the same as below.  An RZ22 would normally only have space
> sufficient for 1 partition.
>              show de:du
>              Device    Status                   CSR         Vector(s)
>             ------         ------                       ---            ---------
>               DU         Resident                172150   154
>                       DU0: is set PORT =  0, UNIT =  0, PART =  0
>                       DU1: is set PORT =  0, UNIT =  0, PART =  1
>                       DU2: is set PORT =  0, UNIT =  0, PART =  2
>                       DU3: is set PORT =  0, UNIT =  0, PART =  3
>                       DU4: is set PORT =  0, UNIT =  0, PART =  4
>                       DU5: is set PORT =  0, UNIT =  0, PART =  5
>                       DU6: is set PORT =  0, UNIT =  0, PART =  6
>                       DU7: is set PORT =  0, UNIT =  0, PART =  7
?KMON-F-Illegal command
?KMON-F-Illegal command

(RT11 Version to old?)


Device      Status       Vector
   US      Not installed  410
   DL      Not installed  160
   RK      Not installed  220
   DY      Resident       264
   DX      Not installed  264
   LP      146676         200 204
   SC      143332         000
   HC      Not installed  330 334
   BS      Not installed  300 304
   VW      Not installed  270 274
   NL      Installed      000
   LS      Installed      200 204
   MS      Not installed  224
   MM      Not installed  224
*  DU      141440         154*

So something happens and we have a first progress.

> Since you already did a SCSI format from the controller or if the drive
> was previously formatted, you will not need to repeat this. The RT11 FORMAT
> command does NOT support this as an MSCP device.  Note: the handler can be
> configured to more partitions and disk space than actually exist on the drive.
> You can examine the contents of the drive to see if it readable.
>              dump/term du0:/end:1
Dump is unfortunately not available on my disk by now, but will add 
them, when I have moved the RX02 back to the other PDP.
> If the handler loads but doesn’t access the drive, check the vector address first.
> Once you are sure the contents are not needed, you can try an initialize.
> Good luck.
> Jerry
> jsw at ieee.org

Is it maybe better to start with a newer version of RT11?
In the meantime I have managed to test RX02 Imaging with Joeg Hoppe's 
PDP11GUI. Works perfect and looks like a great tool.
If I load the MSCP driver via PDP11GUI and use address 160340 I can also 
dump the DU0 (RZ22) disk to my PC, so it seams to be working.

I have not found a newer RX02 RT11 Distribution Set by now, do you have 
some tip were I can find and download one?  Google doesn't return any 
rx02 files, only ready to use images for RK/RL, ....

Many thanks for your Support


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