MBF=

MBF=

Specifies the multibuffer count for a data set

Language element: data set option

Default: 2 for files opened for update; 1 for files opened for input or output

Engines: CONCUR

Valid as: data set option, engine or host option

OpenVMS specifics: All aspects are host-specific

Syntax
Details
See Also

Syntax

MBF=multibuffer-count

multibuffer-count: is the number of I/O buffers that you want OpenVMS RMS to allocate for a particular file. The value can range from 0 to 127, and it must be an integer. If you specify MBF=0, the process's default value is used.

Details

A multibuffer count of 1 is adequate to process your data set sequentially. However, for random access, it is more efficient to use more than one buffer to store various parts of your file in memory. For example, to tell OpenVMS RMS to allocate five buffers for every file in a data library, use the following statement:

libname test concur '[mydir]' mbf=5;

The MBF= data set option corresponds to the FAB$B_MBF field in OpenVMS RMS or to the CONNECT MULTIBUFFER_COUNT attribute when you are using FDL. For additional details about the FAB$B_MBF field, see Guide to OpenVMS File Applications.

See Also

Using the CONCUR Engine

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Language element:	data set option
Default:	2 for files opened for update; 1 for files opened for input or output
Engines:	CONCUR
Valid as:	data set option, engine or host option
OpenVMS specifics:	All aspects are host-specific