The BN38C-01 Ultra 68VHD/68VDKabel f. DS-BA35X-FA controller implements the Digital Storage Architecture (DSA) and allows SDI disk drives to be used with a variety of UNIBUS system configura- tions. The BN38C-01 Ultra 68VHD/68VDKabel f. DS-BA35X-FA is an intelligent controller containing two high-speed micro- processors for host and disk communication as well as data routing in and out of the onboard BN38C-01 Ultra 68VHD/68VDKabel f. DS-BA35X-FA -01 Ultra 68VHD/68VDKabel f. DS-BA35X-FA memory buffers. The UDA50's advanced design permits the controller to handle disk data rates up to 3 Mbytes per second. The controller consists of two hex modules that can be mounted in any two adjacent UNIBUS slots. E ach controller can attach up to four radially connected SDI disk drives in any combination of BN38C-01 Ultra 68VHD/68VDKabel f. DS-BA35X-FA and RA60. • Stores up to 20 host requests for disk seek optimization • Provides for buffering of up to 52 disk sectors in order to smooth the data rates between the high-speed disks and the host UNIBUS port • Allows BN38C-01 Ultra 68VHD/68VDKabel f. DS-BA35X-FA direct controller-host memory transfers • Indicates fault conditions an LED displays and in a hardware register that is readable by the host • Aids subsystem troubleshooting by logging the last fault in an error register BN38C-01 Ultra 68VHD/68VDKabel f. DS-BA35X-FA-A UNIBUS controller for SDI disk drives.