Stuck on "Correcting Errors in the Bitmap"

I am running Windows XP SP3 on my computer, and have a 1TB secondary media drive with about 650 GB of data on it.

When I attempted to copy a large file onto the drive, it stalled for a couple minutes, and then returned a delayed write error. After that, the drive was missing.

I decided to reboot as I was remote at the time, and it automatically ran chdsk on the drive. After about an hour it seemed to locate a couple bad sectors, then went through finding orphan files, and then determined that there was some free space that was marked as allocated.

It then said it was correcting errors in the volume bitmap - and it has been there for about 24 hours.

I am starting to think that something is wrong, but I don't want to cut it off it is actually still working. Is this length of time normal for a drive this size, or is something wrong?

I am very eager to get in there and find out what data is salvageable....