Device Not Ready??? or is it?

Hi,
Found this rather interesting just thought I'd like other takes on it.
A Dell Poweredge server 2 HDD controllers (SCSI) running NT 4.0-the driives are simply mirrored Server is up there in age a ripe old 4 years old (isn't that like a hundred and something in server years?)
Anyway booting it up First controller picks up Seagate drive (scsi id 0, assigns drive c) .
Then comes the second controller picks up and identifies the Seagate drive but then stops for a moment right before assigning a letter. Then the message Device Not Ready appears. Hmmm this could indicate a problem.
So it continues to boot to NT. The previous message concerned me so I went to Disk Administator. The disk is reported as healthy. Well that wasn't enough for me so I broke the mirror. Once broke there was indeed a D: drive now and I had no problems exploring it. Hmmmm looks like its ready to me. So then I reformat it via Disk administrator, it reformats fine. I boot up and same thing as previously mentioned.
I then delete it so I can recreate mirror. I recreate the mirror and reboot. ONce again the Device Not ready error on second drive.
It boots up and after a little bit of time initializing(normal initiialization time for mirroring) the disks are once again mirrored and report is Healthy. I ran NT Disk Admins disk check and that came out ok but I don't know how much validity to hold in that.
Short of changing drives or breaking mirror and pointing NT to boot off of D: and troubleshoot from that point (ie if doesn't boot switch to the known good controller to test HDD versus controller), etc is there any thing else I can do to check? I mean as said NT seems to think it is OK.
So what do you think? Is it controller or HDD starting to go and perhaps NT doesn't realize it yet?

Have a Good Day!

Backup the info and then try swapping drives (drive d to c and c to d) and see if you get past the initailization screen. If it gives you the same error on the d drive (formerly c) then I would suspect the conrtoller. Just a thought.

THanks for the input. Yeah I might just end up doing that. I just found it wierd that there is a total disagreement and NT seems to be OK with the drive. It could just be beginning to go bad and NT just doesn't know it yet???