COBOL Manual for TNS and TNS/R Programs

Environment Division
HP COBOL Manual for TNS and TNS/R Programs—522555-006
6-52
FILE-CONTROL Paragraph
The file-control entry can contain at most one ALTERNATE RECORD KEY clause
that describes a particular alternate record key of the file.
If a file in the file system is defined as having alternate record keys to which the
COBOL program does not make any reference, you do not need to specify them in
the File-Control paragraph.
•
Sequential Block Buffering
Sequential block buffering, enabled by the RESERVE clause when the file is open
in INPUT or I-O mode, is discussed under File-Control Entries for Sequential Files.
•
Buffered Cache
Buffered cache, enabled by the RESERVE clause when the file is open in
OUTPUT, I-O, or EXTEND mode, is discussed under File-Control Entries for
Sequential Files.
•
HP COBOL Fast I-O (Local Buffering)
HP COBOLFast I-O is an enhancement in input-output performance beyond that of
sequential block buffering or buffered cache. It is available if:
°
Either the program runs in the non-CRE environment and the file is organized
sequentially, or the program runs in the CRE (in which case the file can have
any organization).
°
The files upon which HP COBOLFast I-O is to operate meet the criteria under
File-Control Entries for Sequential Files.
•
Performance Penalty for Poorly Organized Indexed File
If a large number of entries have been added to and/or deleted from an indexed
file, accessing its records in sequence requires a significant amount of random
processing; therefore, performance suffers.