Concepts 8.1 MyISAM Tables MyISAM is the default table type in MySQL Version 3.23. It's based on the ISAM code and has a lot of useful extensions. See section 16.4 Using myisamchk for Crash Recovery . You can compress MyISAM tables with myisampack to take up much less space. See section 15.12 The MySQL Compressed Read-only Table Generator .
All data is stored with the low byte first.
This makes the data machine and OS independent. All number keys are stored with high byte first to give better index compression. This will improve the space utilization in the key tree. BLOB and TEXT columns can be indexed. NULL values are allowed in indexed columns.