NT uses only 1GB on SCSI Drive

I have a new server clone with a SuperMicro P6DBS motherboard, with an Adaptek 78xx SCSI controller and two 18GB SCSI drives. When I try to load Windows NT 4.0, I get a very verbose message saying that I can only create a 1Gb partition. I checked my CMOS settings for use with SCSI, making sure that size extension is enabled. Nothing seems to work.

Is there a trick that I’m missing?

Thanks,

Kathy C.