Linux not seeing all SATA drives

[Dennis Wicks]

I have 3 SATA drives on my system. I replaced all my red 
cables with new black cables. The BIOS sees all of them but 
when linux finishes booting it only sees two of them. Do I 
have to do something to linux so it sees the third drive?

FYI, I have the system disk in sata-1, the drive on sata2 is 
not seen, but the drive on sata3 is seen and in use. The 
CD/DVD drive is on sata6 and is also seen.

Thanks for any and all help!
Dennis