I did a cross install of Jessie from Wheezy. When the system is booted, there is a symlink from /etc/mtab to /proc/mounts, but /proc is empty or not mounted. This has some consequences.
I mount proc: # mount /proc Now mount displays what is mounted, and proc is mounted. mount: /proc: mount failed: Unknown error -1 In my host Wheezy system, # mount shows proc as mounted, although there is no line to do it in fstab. But in the target Jessie disk, /proc is empty and not mounted unless this line is present in its fstab: none /proc proc defaults 0 0 My question is: a) how can my Wheezy system mount proc when there is no command fstab to do it? b) why does my Jessie system not mount proc and thus populate /proc unless the line is present? Haines Brown