The BN31K-0E KZPSC-YB Ext. Kabel implements the Digital Storage Architecture (DSA) and allows SDI disk drives to be used with a variety of Q-bus system configurations. The BN31K-0E KZPSC-YB Ext. Kabel is an intelligent controller containing two high-speed microprocessors for host-disk communication and data routing through the BN31K-0E KZPSC-YB Ext. Kabel's onboard memory buffer. The BN31K-0E KZPSC-YB Ext. Kabel's advanced design allows for the controller to han- dle disk drives with sustained data transfer rates of up to 750 Kbytes/second. The controller consists of two quad modules that can be mounted in adjacent Q-bus backplane slots. Each controller can attach up to four radially connected SDI disk drives in any combination of RA81 or RA60. • Stores up to BN31K-0E KZPSC-YB Ext. Kabel host I/O requests for disk optimization • Provides for buffering of up to 41 disk sectors in order to smooth the data rates between the high-speed disks and the host Q-bus port • 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 registry BN31K-0E KZPSC-YB Ext. Kabel Q-bus controller for SDI disk drives.