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[02.07.01]
02.07 Input/Output Facilities of the 709/7090 Commercial Translator
A. Introduction
Input/Output operations are handled within the Commercial Translator system by the 709/7090 Input/Output Control System.
This section is intended to explain how data may be organized and the commands used for efficient input/output. Examples are given to illustrate usage, and appropriate references are made to the General Information Manual and to other parts of this publication.
B. Definitions
1. The Record
A record is a logical grouping of fields. (See the Data Description section of the Commercial Translator General Information manual). A record is made available for processing from an input file by the GET command. The data so obtained may then be operated on by internal commands, such as SET and MOVE. A record is placed in an output file by the FILE command.
2. The File
A Commercial Translator file is a collection of logically related records stored in an external medium, such as tape or cards. Characteristics of a file are specified in the Environment Description (02.06).
A file is referenced by the commands OPEN and CLOSE to initiate and complete file activity. (See Commercial Translator General Information manual).
3. The Block
Physical segments of data in a file are called blocks. A block may consist of any combination of records or parts of records. Four factors determine block and record relations: specified block size, whether records span the boundaries of the block, whether every record of the file begins a block, and whether each record is the block on tape (see SPANS, HOLD, BEGIN, BLOCK CONTROL and BLOCKSIZE in the Environment Description section, 02.06).