MyISAM was the default storage engine for the MySQL relational database management system versions prior to 5.5 released in December 2009.
MyISAM is optimized for environments with heavy read operations, and few writes, or none at all.
To defragment rows and claim empty space, the OPTIMIZE TABLE command must be executed.
[2] Versions of MySQL 5.5 and greater have switched to the InnoDB engine to ensure referential integrity constraints, and higher concurrency.
MyISAM supports FULLTEXT indexing and OpenGIS data types.
MariaDB has a storage engine called Aria, which is described as a "crash-safe alternative to MyISAM".