Shouldn’t any halfway decent file system cache the contents of a file so that the hard drive doesn’t spin up each time? The only time it should spin up would be if the file contents changed, which only happens on write.
Totally unrelated to that I have a few bug reports:
1. The values in the sprinkler log are getting adjusted by the timezone offset. For example, if my sprinkler went off at 1:00 PM and I’m in the -8:00 offset timezone then the log is showing that they went off at 5:00 AM. I took a look at the SprinklerChanges.txt file and see that it is recording times and dates without timezones. It appears that your log display code is incorrectly assuming those times in the file are UTC but in fact they’re being recorded in local time.
2. Program preview shows all the zones starting at the same time. When I look at the interval program and when I actually observe the program running it actually does the zones sequentially. It seems like even though the Interval program for Pi doesn’t have the sequential option to select, it defaults to running the zones sequentially.