Abstract: A network of digital modules having store-through and non-store-through cache memories, is provided with intercommunication capability by means of two sets of system busses each of which are replicates of each other. The system busses provide a higher throughput by both being available to each of the digital modules so that a requesting digital module can alternately use a second system bus if the first system bus happens to be busy. Failure of one system bus will allocate transmission service to the second operating system bus thus providing redundancy. Alternatively, each of the system busses can be isolated for partitioning the digital modules into two different operating systems which are independent of each other.

Abstract: An Input/Output Module (IOM) interfacing multiple computers attached to a dual system bus. The IOM provides an interbus module which interfaces the dual system bus to a sub-requestor bus connecting multiple sub-requestor modules. The sub-requestor modules control a plurality of interface adaptors permitting data transfers to/from a variety of peripherals using different data protocols and clock rates. The requirements for the main host processors and memories in a computer system would be unduly burdensome were it not for the relief from these overhead operations by the input/output module which provides the tailoring of data transfer capability to and from a multiplicity of peripherals having many different types of protocols and clock rates.

Abstract: A personal computer (PC) desktop workstation using a first operating system is enhanced with a single PC bus extension card (SCAMP Board) within its base housing which connects a second computer system (A-Series) having a large memory, control logic and a 2-inch.times.2-inch IC chip module holding a CPU and control store. The first operating system is organized to act as the I/O and peripheral subsystem for the second computer system so that peripheral connectivity, operational and maintenance interfaces can function with a PC keyboard, screen and peripheral devices. The workstation base housing has a footprint of less than three square feet and six inches height while providing memory and processing ability comparable to mainframe computers which are normally several volumes larger in size.