Hi John, jo...@armadilloaerospace.com wrote on Thu, Aug 06, 2020 at 04:28:53PM -0700:
> I was considering making a kernel patch that reported it was > an exFATfilesystem Sounds like a layering violation. The table of file system IDs is in userland - /usr/src/sbin/fdisk/part.c - rather than in the kernel, so the kernel is hardly a natural place for figuring out what kind of filesystem is supposed to be on the partition. > when the mount failed, which you would see if you were onttyC0, or could > call up with dmesg, as with the kernel messages thathappen when you first > plug a drive in. > Is there a concise "philosophy" of when the kernel should print amessage > post-boot? Just when devices are dynamically configured? I would put it as follows: kernel printf(9) is for 1. boot messages (before init(8) starts) (hotplugging hardware is similar even though it happens later) 2. catastrophic kernel failures (like panics) 3. catastrophic hardware failures (like a dying disk) 4. debugging and data collection during active development System-level errors (in particular from daemons) are usually reported via syslog(3) instead. Simply user errors like this one are reported by the application program on stderr. Yours, Ingo