Adaptec Raid Card

[RANJAN_8]

I have HP Server Tc2120, with Adaptec Raid controller card, when i trying to connect 2 hard disk at the same time to the raid card , it wont detects both, but when i connect individual hard disk into raid card it detects the both hard disk and shows the status as optimal, so what will be the problem ?? please some body help me about this...

[e4services]

Sounds as if you are not using a RAID card, but standard SCSI without a backplane to control the SCSI IDs, so my guess would be you have the drives SCSI IDs set to the same, and assuming farther that you had no idea of the need to set the ID, that both drives are in factory state, that is without any setting or set to SCSI ID 0.
Place a jumper on the first ID jumper location on one of the drives.