[HECnet] DECnet for Linux

[Rob Jarratt]

I have the same MFM emulator, it is great, I use it to image old disks and then run the machines from the images. I occasionally get power outages because something in kitchen trips an RCD, the SIMH instances on the Pi have always survived this without a problem, although a clean shutdown mechanism would be nice. However, unless you get extended power outages, then perhaps something like this would work: https://www.pi-supply.com/product/pi-ups-uninterrupted-power-supply-raspberry-pi/. I can’t say I have tried it myself, but it is a nice idea.

 

I think the network problem with Pi is hardware, it seems to become unreliable after a while, despite a reboot. But it does take quite some time before it becomes a problem, so at the price, I think it is fine to get a Pi.

 

Regards

 

Rob

 

From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On Behalf Of Mark J. Blair
Sent: 27 January 2018 19:14
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] DECnet for Linux

 

 





On Jan 27, 2018, at 11:01, Rob Jarratt <robert.jarratt at ntlworld.com <mailto:robert.jarratt at ntlworld.com> > wrote:

 

I run SIMH on a couple of Raspberry Pis without issue, one running VMS 5.4 the other VMS 7.3. They each run as cluster members so I have a cluster for 5.4 and 7.3 running at all times. It is very straightforward. I have even set it up to automatically boot SIMH when the machine is powered on using a tool called “screen”, so I can run it completely headless. I have found that the Raspberry Pi networking starts to get a bit unreliable after running these machines 24 hours a day for a few years.

 

I have SIMH running on a BeagleBone Green, though I don't have a lot of time or use on it yet. It's just the native DECnet support under Linux which doesn't work out of the box using the source in the kernel distribution and the userland stuff available via apt-get.

 

One thing I'd like to look into for a full-time server is whether I might be able to have host system shutdown trigger a VMS shutdown on the emulated system, or alternately, just halt and checkpoint the emulation. That could be nice in conjunction with a supercap-based backup supply for the host computer, so it can have time to shut down when the power unexpectedly drops. I have an MFM hard drive emulator designed by David Gesswein which is built around a BeagleBone, and it has supercap-based backup to let it be embedded inside an old computer and simply powered on and off without worrying about performing a shutdown on it first. When the power gets yanked, the supercaps keep it running long enough to shut down and dismount its filesystems cleanly.

 

Is the network unreliability that you mention just a matter of high uptime? Does an occasional reboot fix it, e.g. by resetting memory leaks?

 

 

-- 
Mark J. Blair, NF6X <nf6x at nf6x.net <mailto:nf6x at nf6x.net> >
http://www.nf6x.net/

 

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