Recent content by leegleason

There's some power wiring info here https://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-186AA-MG-001.pdf

Good news here - I swapped RQDX3s and it now does backup/image with no problems. My obsessing on it as a likely software problem reminds me of the time I worked a carburetor problem on a car for a whole year only to realize it was a distributor problem the whole time. So now I can harvest the...

I'll give that a try. Should be less "demanding" than an image backup. I'm now starting to think that I have a system memory settings problem. Reason being, that I tried to load the Watchpoint driver, to set a memory watchpoint to see if anything was messing with the status in the disk's...

I'm playing around with a MicroVAX I system, running MicroVMS 4.7, in a BA23. Two emulated RD54s for disks, 2.5 MB of memory. I want to backup the system disk to the other disk. Trying $ mount du1: /for $ backup/image/ignore=interlock du0: du1: %BACKUP-F-WRITEERR, error writing DU1...

Ah, thanks for the offer. I actually have one legit cable, in use on another system, so I know how they look. I've worked with coax in radios for a long time and I've never seen anything like these connectors. Closest I've seen to it is SMC - it's the only connector family I know of that has the...

I'm starting to experiment with the VCB01 again - this time installing one a MicroVAX I. I found a cabinet kit for cheap, but it didn't have the mini coax cable with it. In your work with the card, did you have occasion to figure out what sort of connector the coax cable uses? I've never seen...

If you want to install VMS (and you should...) the hot setup is to boot it as a satellite member of a cluster (SIMH or real) and use BACKUP to copy VMS to the local system disk.

Lessee...I did a bit of hacking on the PDT-11/150 roms a while back. They are NS82S2708 mask programmed parts. They equivalent EPROM would be a 2708. These are older EPROMs that required multiple voltages and aren't usually supported by modern EPORM programmers. If your programmer doesn't, it's...

The program is cleaned up and more readable now. It's available at https://rsx11.blogspot.com/2025/05/mscp-and-dup-talking-to-rqdx3.html.

I have to clean up my test program so it's readable, it's a mess right now. The documentation is sparse. First you need to know how to talk plain old MSCP, it's middlin' well documented in Mass_Storage_Control_Protocol_Ver_2.4.0_Jun92.txt, avaialbe lots of places. You need to know how to use the...

OK, this "challenge" got me to thinking about how to accomplish this using an RQDX3 on a MicroVAX without altering the ROMs (although the ROMs do look like they have several hundred bytes of unused space that is going to waste....). A little research showed that it's possible to use DUP to load...

Here's a crazy solution (that I might try for laughs) - change the ROMs on an RQDX3 to blink the LED on the edge of the card. As added challenge - do it without disabling its functions as a disk controller.

I think the most minimal way to accomplish this would be using the T11 chip, technically a PDP11, and "hijack" one of its pins to flash the LED by way of a "funny" program (maybe DAL15 or WT). If you're talking using a complete real PDP11 system, lots of ways to flash an LED from the console or...

>Any particular reason you're running a MicroVAX I? It's rare and interesting. I like MicroVAX2000s as well. I have a taste for the bottom end of the performance curve. I used to own a VAX 11/725 driving a VAXstation 100...this is all purely a hobby activity for me - it doesn't matter how...

Thanks all, for the replies above. On the remote chance that any other MicroVAX I fans see this question (we're scarce - even rarer than MicroVAX 2000 fans), I'm following up with my findings. First, I made a mistake in my statement of the question - I had the CPU in slots 1 and 2, the first...