Thanks. Yes, I’ll try that this weekend. This morning I tried to connect to the default webpage (at port 80 rather than Interval at port 8080) from a different computer, one from which I’d never accessed that page, and it timed out. So I think my assertion that I was successfully connecting to the Pi was wrong – it must have been a cached page on the other PC.
It occurs to me there was another strong clue, of perhaps something starting to go south – I recall now that the last time that I was successfully connecting to the Pi, there were some intermittent delays communicating with it. For example, I had ssh’d into it to do some browsing (looking at the OSPi code), and every once and a while I’d get a delay – in the ssh terminal, there’d be no echo of the typed characters for several seconds, and then they’d all echo back at once. This occurred not long after I’d installed avahi, and I was thinking “that single core processor just can’t keep up.” But that could have also been a symptom as you suggest of the SD having intermittent errors.
Will I find linux system logs on Raspbian?