Loading drivers from an HBA diskette is similar to how DOS
  users load atapi.sys and mscdex.exe for DOS.  Adding drivers
  lets the OS access the device.

     In Uw7/OSR6, there's no error if you don't load the right driver.
  What will happen is no cdrom will be listed to install from.

     Some IDE cdroms need a newer driver that's not on the
  Uw7/OSR6 HBA diskette that came in the media kit.  Check

            ftp://ftp.sco.com/pub/unixware7/714/drivers/

            ftp://ftp.sco.com/pub/openserver6/600/drivers/

  for the latest HBA diskettes.  Follow these guidelines to get your
  IDE cdrom recognized during ISL.

      1)  Set the ide cdrom as the secondary MASTER if it's alone on it's
          controller.

      2)  Otherwise set it as the slave to a master hard drive.

      3)  During ISL, when asked for HBA diskettes:

               *  load the ide_hba_#### diskette first.
               *  load the hba_711a diskette last.

(SCSI cdroms are handled by the SCSI host adapter they are connected to, which also gets a driver from the HBA diskette)

SCO has done a lot to fix most of the issues with mixing the install controller issues.

            ftp://ftp.sco.com/pub/drivers/uw_version/storage/

  where uw_version is your version like 711, 713, 414

  for the latest HBA diskettes.  Get both.  Create the two
  diskettes.   Follow these guidelines to get your IDE crom
  recognized during ISL.

<mschalit@pacbell.net>
gerberb@zenez.com