Mechanical APDL Basic Analysis Guide - Ansys

NUM_BUFR is the number of buffers per file stored in scratch space: 1 to 32. A buffer is a chunk of space
used to "hold" data in memory before they are written to the hard disk. The program waits for the buffer
to be completely "filled up" and only then "empties" it onto the hard disk. This prevents frequent disk inputoutput
activity, which can be time consuming.
NUM_BUFR defaults to 4 and can be changed at the Begin level with the /CONFIG,NBUF command. It is
used for the EROT, ESAV, EMAT, FULL, and TRI files. On systems with a large amount of real memory, you
can increase NUM_BUFR or SIZE_BIO (or both) to keep ANSYS solution files in memory rather than on disk.
This can save a significant amount of disk input-output activity and may be practical for small problems
with many substeps.
SIZE_BIO is the size of each file buffer: 1024 to 4194304 integer words (4 KB to 16 MB). It defaults to 16384
and can be changed (on most systems) at the Begin level with the /CONFIG,SZBIO command. See
NUM_BUFR for details.
VIRTM_MB is the amount of total ANSYS work space requested for the current ANSYS session. It defaults to
1 GB (1024 MB) for 64-bit machines or 512 MB for 32-bit machines; it can be changed with the work space
entry option, as explained in the basic concepts section earlier in this chapter. (See Figure 21.5 (p. 313).) You
can also use VIRT_MEM in place of VIRTM_MB to specify the ANSYS work space in integer words.
NUM_VPAG is the maximum number of database pages in memory, ranging from 16 to 8192. The default
value is 8192 for 64-bit machines or 4096 for 32-bit machines. You can change NUM_VPAG or SIZ_VPAG (or
both) to change the amount of database space; see How and When to Perform Memory Management (p. 308)
in this chapter, and Figure 21.5 (p. 313).
Figure 21.5 Memory Diagram in Terms of Configuration Keywords
SIZ_VPAG is the size of each database page: 4096 to 4194304 integer words (16 KB to 16 MB), defaults to
16384 (64 KB). You can change SIZ_VPAG or NUM_VPAG (or both) to change the amount of database space.
SIZ_VPAG also affects the size of the page file; see NUM_DPAG.
NUM_DPAG is the number of database pages on disk: NUM_DPAG defaults to 1048572 (the maximum). This
number times SIZ_VPAG determines the maximum size of the page file (Jobname.PAGE), which is written
only if the database becomes too large to fit in the database space in memory. If the page file is written,
sufficient disk space must be available to accommodate it, or the program will abort.
MEM_GROW is the starting size of the memory block (in MB) that ANSYS will attempt to allocate should a
problem grow larger than will fit in the current scratch space allocation. If ANSYS attempts to allocate additional
scratch space, it will start with a memory block size equal to MEM_GROW and then reduce this by
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Sample config130.ans File
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