Mac desktops forum: Major Hard Drive Problems

That sounds like you've got a lot of circumstantial evidence all pointing to a HDD failure, and replacing the HDD in the 20" white iMacs is a real PITA. Granted just about everything with those units is a PITA, but the HDD ranks up there as being one of the more annoying.

Given the unit is around 6 years old, it's probably about time for the HDD to fail. Though you can try Bob's suggestion and boot from the install DVD and then see if you can use disk utility to format the drive and use it again.

Otherwise, you'll probably want to call around and find out what it would cost to get the drive replaced, and weigh that against just getting a new iMac.

Also, just a mild bit of trivia, but "disk0s2" is the BSD device name for the drive. Not that Apple goes out of its way to promote it anymore, but Mac OS X is based on a variant of Unix named Darwin which was derived from FreeBSD, which in turn ultimately traces its roots all the way back to the original BSD Unix from like the 1970s. What we commonly think of as Mac OS X is merely the Aqua GUI which is little more than a program running on top of Darwin. If you know where to look, even inside Aqua, you'll find references to things like "disk0sX" where "X" is some number between 0-9 (in computer programming languages, you always start with 0 when you've got a list of things). So disk0s2 means it's the first disk and the third partition on the disk, which if you want to get even deeper into the weeds, just means it created a logical partition. None of this is anything you really need to make an effort to commit to memory, it's just some supplemental trivia. The one thing to take away from this is that if you ever see something like diskXsY where X and Y are some number between 0 and 9, like you are now with disk0s2, then that's a very good sign that your drive has failed in some catastrophic way.