Recent content by cruff

It looks like it isn't dying due to excessive swapping from your graphs, so maybe a possible NetBSD issue? If you run the compile 'niced' does it change the behavior? I wouldn't think it would, but might be worth a quick test.

I never used CP/M much when it was the new thing for S100 computers, but did have access to a couple of Northstar Horizon computers in high school that I could use after classes for a while. Learned enough about that system to recover most of the file from a corrupted floppy disk for the physics...

You can try a flux remover spray to see if that gets the flux off the board. The can I have seems pretty effective at removing rosin based fluxes. You might need to remove the ICs to see if there is trace damage under them from battery electrolyte if the board doesn't work, but your component...

I'd have expected that if it compiled without complaint it would work for the types of images it handles. Like I said I haven't had the time to try it out yet on anything.

This might be useful on Linux: https://github.com/RetroFloppy/imd2raw I haven't used it yet for converting .imd files.

Double check for capacitor leaks have caused corrosion of signal traces causing opens too.

It's almost always worth it to reflow solder that looks iffy. Just don't overheat them so that the connector housing melts.

Won't your circuit assert /DMR not only on instruction fetches but on any data read/write accesses due to /ALE? It seems to me that with the prefetch buffer, the best you can do is stop when an instruction is being read from memory by looking at the AIO signals. I think the J-11 doesn't provide...

That's a nice write up. Does the 500 have a engineering/manufacturing test connector (J32 on the AXPpci33)? I think this would be the obvious location of the transmit and receive pins for the SROM console port, but of course DEC doesn't describe the connector pin out and I've never seen a...

I see what appear to be poor solder joints on the solder side on U20 the MAX202 chip, which is the RS-232 interface. Also on the component side picture I can't see what's between U20 and the serial connector.

Have you verified the serial port baud rate is set to the same speed, parity and stop bit settings expected by your computer? Have you checked for bad or missing solder joints or shorts between pads yet? What types of test equipment do you have to help diagnose problems?

The initial boot load from SROM runs entirely in the CPU cache. A version of the SROM source for the EV4 CPU does talk to serial port 0 with a 9600 baud rate. For the AXPpci33 board selecting bits 1 or 2 of the SROM to load enable the boot service console.

Is the interior filled with dust or other contaminants? Maybe it can be cleaned easily and it isn't the flyback itself.

I use an RRD45 CDROM fine on my 4000/90 running VMS 7.3 along with a combination of old disks and a version 5 SCSI2SD with the built in SCSI controller. Is your CDROM jumpered for 2048 or 512 byte sectors? That made a difference for some older equipment. Just noticed you said it was set for 512...

The obvious searches including terms "SURP" or "6502 6845 computer" didn't produce anything quickly. But obviously a 6502 computer using a 6845 video chip and a 50 signal expansion bus. Enough information on the PCB to build one, you could reverse engineer the schematic to figure out how to...