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
|
-
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.
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.
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
