What could cause /DEV to clear out?

[babak badaei]

Hello, 
 
Today I was not able to log into my machine using SSH. I got this following message "Server refused to allocate pty". I was, somewhat fortunately, able to log using SCP. So SCP works. The file system looked good for the most part; until I checked out "/DEV". Almost everything was GONE! Including MAKEDEV. Not sure what to do.

Possible clue: Before this happened, last time I was actually logged in via SSH, I ran a dropdb command on one of my postgres databases and got an error message saying I did not have permission to "/DEV/NULL". Not sure what to do, I set permissions to allow write on "NULL". I have done "dropdb" many times before and had never seen that message.

I hope this is in the right forum. This is the closest thing to right place for this question in my mind but if this is in the wrong place please direct me to the right forum.

I appreciate your insights and wisdom. Thanks!