Directives

SET_NBF Set Number of Keyed I/O Buffers

Format	SET_NBF buffers   Where:
	buffers	Number of internal key I/O buffers. Numeric expression.
Description	Obsolete.
*Note*	This directive is included here for completeness only. SET_NBF is obsolete and has been replaced by the 'BF'= System Parameter.
	Use the SET_NBF directive to adjust the number of internal buffers to be used by the key I/O manager. Use values in the range 0 (zero) to 25. By allocating more buffers, you can typically obtain better Keyed access performance. Normally the default of 10 buffers yields good overall performance. If you use the 'BF' parameter to set the number of buffers to zero, this will force ProvideX to allocate local or file-specific buffers (controlled by the parameter ‘FB'). Using this directive to optimize system performance takes a great deal of experience. Many factors influence the number of buffers required. The system may slow down if too many buffers are assigned, causing excessive queue searching. Too few buffers may cause additional disk I/O’s. In a single user environment (e.g., MS-DOS) more buffers will typically improve performance, since ProvideX will use these buffers to cache disk reads and writes.