I've been working on a problem with a /dev/null file on an AIX system (just for background it looks as though it was inadvertently deleted and recreated as a normal file by somebody), but in trying to determine what caused the problem, I noticed that the timestamp on it seems to update every minute. I've observed this on several AIX servers at my workplace.

At present I can't entirely rule out this be something specific to the Application being used at my workplace, so I compared with CentOS and Debian based computers at home last night.

The CentOS box, which runs 24 hours, had a mod time on /dev/null of around 4 days ago (during which time it was essentially just being used as a web browser and multimedia player, although it would have had active but essentially unused Apache, MySQL and VMM processes running in the background).

The timestamp on /dev/null on the Debian machine, which was a just booted laptop, pretty much reflected the boot time, but I tested redirecting STDIN from, and STDOUT to it, and the modification time was unchanged (I'm not sure 100% sure if directing data to /dev/null constitutes "writing to it" in the way it would a normal file).

So my question is essentially, could anybody please offer any advice with regards to what circumstances (permissions changes etc.. aside) might cause the timestamp on /dev/null to update?

Thanks very much for any suggestions.

Alex.