DZWRITE

  Recently I decided that I could reduce the storage space consumed by the assorted small PDP11 parts here by assembling some of them into systems. I had a BA23 cabinet and a pretty good selection of QBUS cards to work with. I installed an 11/73 CPU, a memory board, a DLV11J, a DHV11, an RQDX3, an RX50 and an RD53.

   The RD53 needed formatting, so I needed XXDP running on the system. I tried to use VTserver to load XXDP into memory, but, for some reason, it doesn't seem to play well with Windows 7 as the host. I spent quite a lot of time trying to debug it and discovered that it often completes IOs without bothering to get any input characters. This confuses the rest of the program (and me).

  Growing weary of Microsoft and Visual C++, I looked for another solution. It occurred to me that my old PRO-380 (formerly a VAX Console) had RX50s on it as well, that would allow me to create media for the 11/73. I dusted it off and spent a couple of days troubleshooting it. It was having all sorts of disk errors. I spend several days formatting and testing a goodly number of ST506 disks before I realized it was a bad disk controller card. I popped in a spare and all was well. After tussling with it and struggling with VTserver, I was glad to get a little closer to the original project again.

  I wrote a little program that will read an RX50 disk image file and write it to a floppy. On the long chance that there is anyone left in the world interested in using a PRO running P/OS system to support their PDP11, here it is... 

dzwrite.mac

  To use... 
$ MAC DZWRITE 
$ LINK DZWRITE
Insert floppy... 
$ DISMOUNT DZ1: 
$ MOUNT/FOR DZ1: 
$ RUN DZWRITE
DZW>DZ1:=somefile.dsk
DZW>^Z
$ DISMOUNT DZ1:

  The image I used was a copy of XXDP.DSK I found on the web that had the RQDX3 formatter on it. After DZWRITEing the image onto an RX50, I loaded it on the 11/73, and it booted fine. Unfortunately, the RQDX3 formatter sees the RD53 as an RX33, and is reluctant to format it, so it looks like I have some more hardware to sort out on that end...