I have a PC with ADAPTEC 2940U2W SCSI card. I tryed to install RedHat LINIX 5.1 but the installer neither gave me drivers for this card as a choice nor the chance to supply it from let say diskette. So I was not able to install RedHat LINUX 5.1. For comparison, I was able to install Windows NT in spite of the original NT CD-ROM does not have a driver for this SCSI card. During installation when NT failed to match predefined drivers it prompted for the vendor supplied diskette.
The kernel shipped with 5.2 has improved support for Adaptec Cards. I recommend upgrading to 5.2.