Hard Disk Error?

[Andrea Venturoli]

Hello.
I'm managing a server with 4 SCSI drives building 2 vinum mirrored volumes with a Tekram DC-390U2W controller.
A while ago the last drive (SCSI id 3) began giving errors. At first I thought these were temporary failures, rebuild
the disk from its mirror and went on; however, as the incidents started showing up always more often, I removed the
drive, put it into another system and used SCSImax from Maxtor site to diagnose it. This utility told me the disk was
good, so I put it back into the machine. It worked for a while, then started giving errors again.
These days these problems are so frequent that the disk is almost unusable.
I stopped the machine during non-working hours and ran SCSImax directly on it: again it told me the disk is good.
So I tried swapping it with another, thus moving it from id 3 to id 2, just to be sure that it didn't depend on that;
now I get the errors, as expected on da2:

> (da2:sym0:0:2:0): READ(06). CDB: 8 e 67 90 10 0 
> (da2:sym0:0:2:0): HARDWARE FAILURE info:e6793 asc:40,85
> (da2:sym0:0:2:0): Diagnostic failure: ASCQ = Component ID
>  fatal:vinum0.p1.s0 read error, block 419665 for 8192 bytes
> vinum0.p1.s0: user buffer block 419400 for 8192 bytes

Can anyone explain what the codes mean?
Does someone have any hint on how to demonstrate to my dealer that the disk is broken and get it replaced, since it's
well into its warranty period?
Can anyone suggest any other possible reason?

 Thanks a lot
        Andrea Venturoli