QBone in PDP-11 questions

[GreyHairedDECfan]

A couple of questions for those who have used the QBone board:

1. Does the board by itself give you Ethernet connectivity (that the PDP-11 OS can utilize) using the BeagleBone's Ethernet port or do you still need a DEC Ethernet card? I'm guessing the latter.

2. Are you able to utilize the BeagleBone for other applications or is it "sandboxed" (for lack of a better term) to only driving the QBone?

Thank you.

 

[reinhardtjh]

1) You still need an Ethernet card for the PDP. The network connection is purely for the BBB. That could change though. There is nothing to say someone couldn't write a DELQA (or DEQNA but really, why?) emulator like the disk emulators. Just nobody has done it yet.

2) There is no reason the BBB couldn't run other things. Be aware that the distro Joerg used was fairly old because it had the RT extensions and at the time they weren't compatible with the newer kernels (IIRC). I don't know if that is true now.

What other things would you want the BBB to do? It it pretty lightly loaded with the QBone tasks but I don't know that you'd want it doing much else.

 

[GreyHairedDECfan]

What other things would you want the BBB to do? It it pretty lightly loaded with the QBone tasks but I don't know that you'd want it doing much else.

I'm interested in using it as a home file server, I think that would be a somewhat-unique project.

Of course it would need Ethernet and some high speed storage and processor power for that. I could install a Raspberry pi and SSDs inside and that would give me the ability to do that (along with modern storage) alongside the QBone (if I remove all of the DEC cards except the CPU and memory). Giving me a legit PDP running original DEC software, and a file server, in one large box. At least, that's my vision.

 

[reinhardtjh]

You could try it. The PDP side won't be using the BBB network connection so if it's busy serving files that won't bother it. Using too much CPU could affect it. The QBus interrupts are all handled by the two co-processors but disk serving and memory serving is done with both the main BBB CPU and the co-processors. The BBB has just one CPU core so you have to be careful you don't overload it. This is a typical usage when running RSX-11 on a PDP-11/53

Tasks: 115 total,   1 running, 114 sleeping,   0 stopped,   0 zombie
%Cpu(s):  3.3 us,  8.6 sy,  0.0 ni, 88.1 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
KiB Mem:    497680 total,   216824 used,   280856 free,    55596 buffers
KiB Swap:        0 total,        0 used,        0 free.    76080 cached Mem

  PID USER      PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND
 2196 root      20   0   74736  16512   1080 S  3.2  3.3 144:01.47 demo
  117 root     -51   0       0      0      0 S  2.3  0.0 108:50.05 irq/160-4819c00
23679 root      20   0    4560   2012   1644 R  1.9  0.4   0:00.89 top
 1934 root      20   0   26656   9548   4184 S  1.0  1.9  26:08.52 wicd
 1574 message+  20   0    4768   2508   2124 S  0.6  0.5  14:09.92 dbus-daemon
 1963 root      20   0   16624  10808   6476 S  0.3  2.2  13:34.80 wicd-monitor
15619 www-data  20   0  229032   3336   1928 S  0.3  0.7   0:35.84 apache2

 

[GreyHairedDECfan]

That's why I'd use a separate Pi for the file server. It wouldn't interfere with the PDP/BBB at all, just reside in the same enclosure.

 

[Roland Huisman]

The bbb is not really a fast Linux computer. But that was not the purpose of it. And I think you don't want to power your pdp day and night to keep the bbb online for file sharing. To be honest, I would not even think about using the bbb for other purposes on the unibone. Just use a cheap Pi for a file server.

Regards, Roland

 

[GreyHairedDECfan]

The bbb is not really a fast Linux computer. But that was not the purpose of it. And I think you don't want to power your pdp day and night to keep the bbb online for file sharing. To be honest, I would not even think about using the bbb for other purposes on the unibone. Just use a cheap Pi for a file server.

Regards, Roland

Yes, exactly. I would fire up the PDP for special occasions but the Pi (with it's vastly-lower power consumption) would run 24x7 as the file server.

 

[rjm957]

I'd like to know if the emulator for the DELQA has already been written in the last few years.

 

[Hunta]

if the emulator for the DELQA has already been written in the last few years.

PDP2011 – Recreating the world's finest computer system

 

[reinhardtjh]

I'd like to know if the emulator for the DELQA has already been written in the last few years.

Unfortunately, not yet.