Patent GB-1158505-A (GB)
Title: Multi-Computer Apparatus for Real-Time Environment
IPC: G06F15/16
Filed: 1967-01-31
Abstract: 1,158,505. Data processors. GENERAL ELECTRIC CO. 31 Jan., 1967 [25 Feb., 1966], No. 4627/67. Heading G4A. Data processing apparatus comprises a plurality of processors each adapted to execute a different processing operation, a first procensor responding to a particular set of instructions to generate data words and instructions which are sent to a second processor, the latter responding to the instructions to determine if at least one of the data words satisfies a predetermined criterion and if the criterion is not satisfied cause the first processor to provide a second different set of data words. A processing system in an aircraft carrier, used to control landing of aircraft on the carrier, comprises the following units: a main computer, an auxiliary computer, a memory unit (drum or random access, holding data and instructions for both computers), an input/ output unit (servicing a radio link and typewriters), a manual control console (permitting manual entry of data and manual alteration of programme sequence) and a control unit. The control unit essentially comprises series of registers linking the other units of the system. The main computer comprises an instruction register and decoder, an arithmetic and logic unit, two accumulators, and a chain of 21 further registers. Each further register holds one word and can be entered or exited from directly or entered via the previous registers in the chain. The auxiliary computer comprises an instruction register and decoder, a comparator and arithmetic unit, an accumulator and four further registers. As an approaching aircraft gets to within a certain distance of the carrier, and at intervals thereafter, its identity, altitude, range and bearing are radioed (e.g. from a radar station) to the processing system together with an indication whether the aircraft has priority and an indication whether any previous such data group has been transmitted with respect to this aircraft on its present approach. Wind speed and direction are entered manually. In response, the processing system assigns to the aircraft a so-called "gate number," specifying its landing time, and transmits commands to the aircraft. Conflicts in landing times are resolved by " storing " one or more aircraft at one or more different altitudes in a " holding cone." Aircraft characteristics, e.g. optimum speed, are prestored in tho processing system. After processing of the first data group, gate number and course, range and arrival time data for the aircraft are stored, and may be updated in response to subsequent data groups. In response to receipt of the first data group for an aircraft, its ideal (i.e. assuming no conflicts) course, arrival time and gate number are computed by the main computer. The arithmetic and logic unit of the main computer prepares an instruction to cause the auxiliary computer to compare the ideal gate number with all gate numbers already allotted to other aircraft which may be stored on a single track of the memory unit drum. In the case of conflict, provided the aircraft doesn't require priority, the ideal gate number is incremented until it is unequal to every already allotted gate number. If the aircraft does require priority, however, and the aircraft with the conflicting gate number does not, the latter gate number is incremented as before to resolve the conflict. Finally, if both conflicting aircraft require priority, the ideal gate number is incremented until unequal to any allotted gate number or equal to a non-priority alloted gate number. In the latter case, the further conflict is resolved as before. The auxiliary computer also updates the stored range data for every aircraft during each revolution of the memory unit drum. The main computer updates the course data of any aircraft whose gate number has been changed, and the arithmetic and logic unit of the main computer prepares an instruction to cause the auxiliary computer to compare the course with the courses of other aircraft to detect conflict. In the case of conflict, the auxiliary computer sends an indication to the main computer to cause it to alter the course.