PDP-8/I Repair

[m_thompson]

I had some unknown DECtapes which I tried to image with dumprest, but to no avail. I suppose they are probably PDP-10 tapes from the looks of it. I would like to get a TD8E so I can dump them at some point.

The PIP10 program under OS/8 should allow you to fiddle with the PDP-10 DECtapes no matter what DECtape controller you have.

I got a modified version of the TD8E dumprest so I could read/write PDP-9 DECtapes. The same program should be able to image PDP-10 DECtapes.

 

[DougIngraham]

Worked on the 8/I more tonight, as it had been a while since I powered it on. I tried to boot Doug's Console Serial Disk, and it came right up. Exciting! I had some unknown DECtapes which I tried to image with dumprest, but to no avail. I suppose they are probably PDP-10 tapes from the looks of it. I would like to get a TD8E so I can dump them at some point.

So I can update the CSD readme, what OS are you running on the server, what is the server hardware and what speed is the console port? Also, what did you do to update the console port to get higher speeds?

I think you should be able to read DECtapes from any of the machines with a TC08 or TC01. You might need to write something special to do it but the controller should be able to read it.

 

[antiquekid3]

The server is running on an HP EliteBook under Ubuntu 18.04 LTS if I recall. Running it at 19.2k. Check back a bit in this thread and you'll see the hack I made from DJG's code running on an Arduino Pro Micro. I'm using a USB to TTL converter and had to use an additional inverter on either the input or output—can't remember which.

And yes, sure enough, I can use PIP10 to read the directory for some of the tapes. Need to figure out a way to actually image them though. Maybe I'll read up on the PIP10 source and see how they do it.

 

[antiquekid3]

Here's Console Serial Disk successfully booting!



I tried getting the directory of one presumably PDP-10 tape and got gibberish. Others gave an error.



This one spit out exactly the same directory information that was contained within the DECtape container. Cool! Couldn't seem to do anything with the files, but it's also possible that's user error. However, it does seem that it really only will do an image copy to another PDP-10 formatted DECtape...



I plugged in the DW8E power cord and nothing happened. I don't see a remote power connection, so maybe there are some power supply issues...







In the meantime, I tested the RK8E (or maybe an RK8F) controller that came with my DW8E in my 8/M. Visually, it seems to be the same as my RK8E I found piecemeal on eBay years ago, except with less damage. I made a post a while back on that, if I recall.



The set from the DW8E did not pass the diskless diagnostic...



My eBay set I repaired a while back still passes, so that's good.



I then powered up the RK05 and let it filter some air for a while. It eventually became ready and had some activity, though I was never able to read a directory from my 8/M. Not yet sure if I have another issue, or if the disk is simply corrupt.

 

[antiquekid3]

I finally tracked down in my bucket of cables what should be the TU56 to TC08 cable. Based on my assessment, it should be fine for going to the TU55 as well, given the pinout of the TU55 matches the TC01 and TC08. I'll play with that potentially next week. I think the motors feel stiff on the TU56, so it'll probably need work.

 

[tradde]

That sure looks like the TC08 to TU56 cable that I remember.

 

[vrs42]

And yes, sure enough, I can use PIP10 to read the directory for some of the tapes. Need to figure out a way to actually image them though. Maybe I'll read up on the PIP10 source and see how they do it.

I'm trying to do something similar with a program for the PDP-12 called TC12F. It claims to be able to convert between DECtape and LINCtape formats, including some PDP-10 formats.

There also seems to be an earlier version called PRTTC12F for DIAL and a later thing called TC12M, which might be a PQS8 thing. Lasner's name seems to be on all three of the extant source files.

I thought I might be able to modify it to use OS/8 (OS/12?) drivers to write the output image, which would make it easy to archive them. Or perhaps the dumprest format on a serial port.