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Data Set JOIN Accomplished Using I/O Controller Disk Cache Facilities

IP.com Disclosure Number: IPCOM000043673D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Dixon, JD: AUTHOR [+4]

Abstract

A technique is described whereby a disk cache buffer and input/output (I/O) controller facilities are used to save central processing time by creating new data sets, based on logical relationships defined among two or more existing data sets. The concept uses relational data base and file JOIN techniques within the disk subsystem formed by the disk unit and its I/O controller. In information management systems, more and more emphasis is given to the creation of special data sets to meet the individual needs of a user. Data base changes are in the form of additions to existing support. Multiple and special purpose data sets have become more evident since the installation of executive work stations. Usually, a great deal of processing time is required to create special customized data sets.

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Data Set JOIN Accomplished Using I/O Controller Disk Cache Facilities

A technique is described whereby a disk cache buffer and input/output (I/O) controller facilities are used to save central processing time by creating new data sets, based on logical relationships defined among two or more existing data sets. The concept uses relational data base and file JOIN techniques within the disk subsystem formed by the disk unit and its I/O controller. In information management systems, more and more emphasis is given to the creation of special data sets to meet the individual needs of a user. Data base changes are in the form of additions to existing support. Multiple and special purpose data sets have become more evident since the installation of executive work stations. Usually, a great deal of processing time is required to create special customized data sets. However, by solving relational database file JOIN problems within the disk subsystem, significant reduction in processing time can be achieved. The JOIN operation consists of a logical screening operation performed on the contents of two or more input files. Data items from the input files, which pass the logical processing criteria, are copied into the new file created to hold the results of the JOIN operation. Fig. 1 shows the basic concept involved in the JOIN operation. Two input files called FILE 1 and FILE 2 are represented in table form using relational data base notations. The rows represent the logical record. The columns represent different functional items, A to E, which appear in the given logical record. The subscript denotes the value of the given functional item as it appears in the logical record. Therefore, the functional item C has the value 19 as it appears in logical record 3 (row 3) in FILE 1. As the two files are organized, functional i...