Command: mapfile

Syntax

mapfile {<file> ... }

Description

Memory-map a file to improve performance (particularly during rendering) when handling very large files.

Parameters

• <file>
  The name of the file to be memory mapped. There is no default file extension.

Switches

• -sh
  Applying this switch makes the memory-mapping available to other Fire processes to help reduce virtual memory usage.

Notes

When entity files are displayed, they are mapped into memory, processed, then unmapped. Usually this process is very fast, but with very large files (we are talking 20 meg plus here), there can be a delay during the mapping operation. This command ensures that a file stays memory mapped even when it is not being processed. When multiple Fire sessions (different processes) are accessing the same very large files it is expeditious to use the -sh switch to reduce operating system virtual memory usage.

Typically the only files which need to be explicitly memory-mapped are very large entity (.e) instance files. Mapping other file types has little impact on performance, in fact in some cases it is detrimental, needlessly using up operating system resources. An exception is when an entity file is instanced multiple times making the cumulative map and unmap times inefficient, so mapping such files explicitly is often beneficial.

The companion to this command is unmapfile.

Examples

Memory-map a file (florida.e).

mapfile florida.e

Memory-map 3 files, and share the mapping with other Fire sessions.

mapfile belgium.e,holland.e,luxemburg.e,-sh

See Also