dbupgrade operates on the currently open input geometry databasefile in MGED. After dbupgrade is complete, the working database will be upgraded and a backup file will be saved preserving the original "pre-upgrade" version of the .g file. Keep the backup file until it is clear all necessary information was successfully preserved.
Starting with v5, the geometry file format is platform independent. For v4 .g files, however, there is a potential problem in that the floating point storage format within the file is platform dependent. Consequently the safest way to upgrade a v4 file is to run dbupgrade on the file before transferring it from the platform on which it was created. If that system is no longer available, the dbupgrade will attempt to automatically fix an existing (v4 format) binary database that was transferred from a binary-incompatible platform.
The older process of running g2asc(1) and asc2g(1) on a database to preserve a text version as a work-around for platform specific binary files is no longer necessary.
mged(1), g2asc(1), asc2g(1).
Numerous error conditions are possible, usually due to errors in the geometry database. In the case of a binary-incompatible v4 file, some errors may reflect incomplete conversion code. Descriptive messages are printed on standard error (file descriptor 2).
Example 1. Binary Incompatible v4 .g File Upgrade from MGED
bash4.0$ mged -c -a nu model.g BRL-CAD Release 7.22.1 Geometry Editor (MGED) Fri, 08 Feb 2013 15:36:52 -0500, Compilation 0 user@machine:/usr/brlcad/dev-7.22.1
WARNING: Binary-incompatible v4 geometry database detected. Endianness flipped. Converting to READ ONLY. Opened in READ ONLY mode /home/user/model.g: READ ONLY Historical Model (units=in)
mged> dbupgrade upgrade, cancel, or help? [default: help] upgrade mged> q bash4.0$ ls model.g model.g.R4.g
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