The file extension ODS identifies spreadsheets of the OpenSource spreadsheet OpenOffice.Org Calc.
This format is an Open Document for Office application, also known as OpenDocument. Originally developed by Sun Microsystems and based on XML, the standard was developed by the Organization for the Advancement of Structured Information Standards (OASIS).
OpenDocument is the native format of OpenOffice.Org Suite. Ods is the default version of the spreadsheet OpenOffice.Org Calc.
The files contain data in cells organized in columns and rows. They can also include macros and formulas.
Numerous free but also commercial programs support this format.
Microsoft Excel can read from version 2007 SP2 ODS, with older version the ODF plugin must be installed.