meaning of the message

2007-12-24 19:36:00

does any one know what this message mean. and what's the solution to it. I am runnig a Solaris 8 on a sparc 5 box. thank you for your time.
Mar 22 16:03:06 armageddon ufs: NOTICE: alloc: /: file system full
Mar 22 16:06:31 armageddon last message repeated 2 times
Mar 22 16:22:34 armageddon ufs: NOTICE: alloc: /: file system full