Disk Failure (S.M.A.R.T: Fail)

Hello,

Yesterday my computer completely stopped booting: it would freeze at the apple logo with the rotating loading icon. After booting from the Leopard CD and running Disk Utility I had the error message (see attached image). After closing Disk Utility the Leopard setup started so I thought "What, might as well try it" so I went out for a while and left the Leopard setup open. I came back a few hours later, my imac was booted on my old installation of Leopard, all my files / programs still there.

I then launched Disk Utility within Leopard, and got the same error message (see attachment again). It says I should backup everything and replace my hard drive by a "working device".

The error message seems kind of obvious but I was wondering, from past experiences, what does it really mean? I have an external hard drive, should I hurry, back up everything and go buy a new drive as soon as possible? I find it weird it booted if it's THAT critical...

Any advice?

Backup and get another drive soon. Have always replaced mine as soon as I got any type of message like that. It's just never been worth the chance at waiting for it to completely fail.

Have seen drives like this never boot again, and have seen them boot sporadically for 2-3 months.

Like bobtomay said, it is warning of impending disk failure.