GB1216788A - Improvements in or relating to intermediate storage arrangements for data-processing systems and the like - Google Patents

Abstract

1,216,788. Digital data store. SIEMENS. A.G. 25 April, 1969 [26 April, 1968], No. 21210/69. Heading G4C. [Also in Division H4] In a data processing system in which data items can be classified into groups having different degrees: of. priority, data items requiring intermediate storage are each entered into arbitrary storage locations and supplemented by data giving its group priority and order of arrival relative to other members of that group. It is stated that the processing system may be a central control in a telephone. exchange. In the arrangement shown data items from a source Q are entered into intermediate store SI for read-out on demand by a. utilization device E. The intermediate store is an associative store having an address portion SA into which the supplemental data comprising the addresses is entered as the items of data arrive. A device PD (not detailed) determines the priority group to which each item. of data belongs and increments a corresponding input counter such as PG1 : EN1 the output of which is characteristic of the order of arrival of that -item relative to others in its group. Both the group and. order.. within a group designations are entered as an address in SA. In addition to having an. input counter each priority group has an output counter such as. AN1 incremented each time an item of data is read-out. In each group the counters register equal counts only when no item of data having that group priority is stored in the intermediate store. Any difference between the counts is detected by a comparator such as V1. When the data is required by the utilization device E a. device. AS responds testing the group equipments in turn until a group (that of the highest. priority) is found for which data items are stored, this being indicated by the output of the comparator. The addresses of the items (given by the settings of the counters of that group) are entered into a read-out register AR. The addresses in SA are sequentially compared with each address in AR and when a match occurs the corresponding item of data is read out to the utilization device. The item of data is given a number which is transmitted to the utilization and together with the item of data stored for a predetermined time. If the utilization device fails to receive an item or if a parity check indicates an error it returns the number requesting repeat transmission. In a modification in which the intermediate store is stated to be a rotary store a plurality of read-out registers are provided.