Original Publication Date: 1980-Jul-01
Included in the Prior Art Database: 2005-Feb-13
In the past, computer systems implemented with loadable control storage, such as storage 1 in Fig. 1, required special central processing unit (CPU) hardware and interface to communicate with a dedicated initial microprogram load (IMPL) device, such as disk storage drive 4, in order to retrieve diagnostics from that device to perform self-diagnosis on the various components of CPU 2. After completing the self-diagnosis, the CPU retrieves from the IMPL device the necessary run-code to load into its control storage 1 to permit initial program load (IPL) of the system. The master channel arrangement provides the capability to communicate to any attached device in the computer system. Thus, it eliminates a dedicated IMPL device and special CPU hardware.