Console error: "x: Input/output error". System hangs.

[Brian Keener]

Basically, I had a ssh session running on my desktop PC connected to my
server, and was su'd to root. When I executed any command except internal
BASH commands, it would report

"x: Input/output error."
No new SSH session could execute, REBOOT and /sbin/service reported the same
error.

Typeing EXIT to return to my normal login status resulted in multiple instances
of "Segmentation fault".

Nothing seems out of whack in the logs.

Where would you suggest I look for clues?

Brian K