The text read off it
[02.07.03]
The 'transmit' mode is triggered by the selection of the SPANS, HOLD or CARD options on the Environment FILE card. 'Locate' is assumed when none of these options have been selected.
6. Record Types
a) Definition
There are two record types, fixed length and variable length.
i. A fixed length record cannot vary from the length specified by the data description. When it is read or written, a fixed number or words are always made available or output from the buffer.
ii. The number of words in a variable length record is defined at object time by use of the QUANTITY IN option. When it is read or written the current value of the data.name(s) specified by the QUANTITY IN option(s) defines the number of words to be processed. Storage, if the record is transmitted, is always allocated on the basis of the maximum size of the record. The QUANTITY IN clause, by designating that the length of a field within a record is variable in length, identifies the record as being a variable length record.
b) Standard Variable Length Record Format
i. The standard variable length record when contained in an external storage medium or in a buffer area is always immediately preceded by a control word containing the record length. Although this control word is not described as part of the record in the Data Description and may not be addressed by the programmer, it must be considered in specifying block size for a file.
The control word is automatically supplied for standard variable length records generated by the system, and must be supplied for those generated outside the system. The form of the control word for standard variable length binary records is:
IOCTN 0,,length.of.record.in.words.
Standard variable length BCD records must be immediately preceded by six (6) BCD characters specifying the length of the record in words. Facilities for handling non-standard variable length records are described later in this section.
ii. Caution if a variable length record is to be processed in the buffer area (located) it cannot be expanded unless each record in the file begins a new block. No check is made for violation of this rule either at compile time or at execute time.