Anomalous behaviour of JMRI on Raspberry Pi 4B 8Gb

[wilwahabri]

Recent issue on my JMRI installation.

 

It was working fine one day, programming locos and operating trains. next morning neither panel pro or decoder pro would open the comprehensive programmer for any loco on the roster.

 

This is running on a Raspberry Pi model 4B with 8Gb ram and from a 256Gb SSD attached to a USB 3 port. System software is Ubuntu Mate 20.4.

 

This system and JMRI (4.20) combination has been stable since set up about 6 months ago

 

The whole system, when operating satisfactorily, was backed up to another 256Gb USB stick for recovery if required.

 

On failure of the panel pro and decoder pro to operate properly I checked the DCC++EX command station and even reloaded the software - no change. I then fitted the back up system - and experienced EXACTLY the same failure mode with a system and software setup which had been working perfectly 6 months prior.

 

At this point I downloaded the latest version of JMRI and did a complete reinstall, importing my loco roster from storage.

 

All fixed, no further issue!

 

Glad to be operational again, but concerned that two complete systems, one of which had not been used since storing failed for no apparent reason. It raises questions like Linux that reliable? No system changes have been made in the interim. Is there something amiss with the version of JMRI I was running prior to failure was V4.20. currently have 4.24 installed.

 

Can anyone come up with an explanation for this strange behaviour?

[KingEdwardII]

Forget JMRI for a moment, have you been keeping your Ubuntu system up to date? 

 

Have you been updating ANY packages on the Ubuntu system, like using "sudo apt xxx" or "sudo apt-get xxxx"? You might have done so for some other installation on that machine.

 

In principle, it is advisable to keep the Linux system up to date, but this can lead to the need to also update the packages relating to an "application" like JMRI since some of its dependencies might change.

 

The fact that all was OK once you upgraded your JMRI makes me suspicious that one or more of its dependencies got updated and caused an incompatibility.

 

Yours,  Mike.

[wilwahabri]

Ubuntu updates have been installed, however it worked Friday and stopped working Saturday, no Ubuntu updates installed in between.

 

Weird!

 

[KingEdwardII]

OK, so my guess is that some package used by JMRI got updated and the older version of JMRI could not live with it. I can't account for the working one day, failed the next, but that would depend on when a given update actually got used by JMRI.

 

But at least everything was fine after your JMRI update.

 

The number of changes affecting a given JMRI release is startlingly large - I peeked at the GitHub listing of updates for the 4.24 release and there were 870 separate items - OK, some were documentation and so on, but the potential for change right across the JMRI package is substantial. How many of these changes deal with updates to underlying packages is anyone's guess - the dependency list is quite large.

 

I can't promise you that this will not happen again, but it is generally wise to keep things up to date, accepting that this means updating JMRI as well as other components on the Ubuntu system. Especially as some of the Ubuntu fixes might be critical security related updates.

 

Yours,  Mike.

[Harlequin]

I find on my Pi-Sprog system that it randomly changes the state of the "Progamming on Main" / "Edit Only" radio buttons. When it is in "Edit only" mode then the comprehensive programmer window takes a long time to open and, of course, won't change anything.

Simply changing the radio switch to "Programming on Main" gets things working again.

 

Edited August 8, 2021 by Harlequin

[KingEdwardII]

What Pi are you using?

 

I run JMRI on a Pi 400 with 4Gb RAM and it runs just fine.

 

With older Pi models, the lack of RAM can be a major issue and will slow things down considerably.

 

Yours, Mike.