Abstract: A data link processor (peripheral-controller), for managing data transfers to/from multiple disk drive modules, provides a hardware self-test operation to its subsystem card units when it is powered on. The data link processor momentarily disables its interfaces to the peripheral disk drives and the host computer to execute test operations and to indicate either the integrity condition or fault condition of its card units. Each card unit also has a pushbutton for self-test initiation and a local light-emitting diode which lights up and stays lit up if the card unit is misfunctioning to indicate a failed card unit. Further, the connected host computer can initiate the self-test operation for the peripheral-controller for integrity testing.

Abstract: A storage module device-data link processor provides for management of data transfer operations between a main host computer system and up to eight separate disk drive units. The data link processor provides a peripheral interface circuit unit (for selection of a given disk drive unit) and which is connected to a formatter circuit unit and a host adapter access circuit unit. The formatter unit establishes the required protocol format for addressing and accessing a particular cylinder, a particular head track and a particular sector within the selected disk drive unit. The host access unit connects the data link processor to the main host computer while also managing execution of the data transfer operations, including error correction and integrity checking.

Abstract: A data transfer network includes a group of disk drive peripheral units, each has dual ports for connection to two separate peripheral-controllers. A host computer can initiate either peripheral-controller to access selected disk drive units for Read/Write operations.