Jon, Pieter, On Thursday 20 January 2005 01:09, scsijon wrote:
At 07:22 PM 20/01/2005, Pieter Botha wrote:
The thing is that as soon as I get a display (run level 5 is entered), one of the relays are opened. I have set the script to run on all run levels thus it does run on runlevel 5, it just runs before something else. What could the "something else" be? Where can I see in what order stuff are started for runlevel 5?
I may be off line but:
I suspect the port is being "poled" to see if anything is on it by linux and your device (relay) is somehow connected to one of the two control pins instead of just a data port (such as use to be done back when the standard parallel device was the motorolla 6820/1/2) to gain extra device connections without using multipliers.
The most obvious hunch for stock system software that's accessing the printer port is the printing subsym. On my system run levels 2, 3 and 5 start CUPS. Levels 1, 2, 3 and 5 start the hot-plug software. Either or both of these could be causing unwanted interference, but given that the unwanted external device activation occurs only when entering run level 5, the hot-plug software is probably excluded from consideration.
The easiest fix is, if you have a spare still change the relay connection to another, otherwise you need to do some reprogramming to stop the test, and that won't be easy.
By "spare" do you mean a spare parallel port? If so, the interfering software may be accessing all available printer ports. I'd say the easiest diagnostic test is to disable CUPS for run level 5 temporarily to see if the symptom is alleviated. If it is, then fix the CUPS configuration so it does not include the parallel port used by the remote irrigation control system.
regards scsijon
Randall Schulz