ODS was a format developed by Sun Microsystems and is used by the OpenOffice and StarOffice suites. The ODS file extension is given to files that are created with the calc program - a spreadsheet application which is XML based but contains spreadsheets, charts and other graphical elements held in rows and columns much like Microsoft Excel.
The OpenDocument Format (ODF) is an XML-based file format for representing electronic documents such as spreadsheets, charts, presentations and word processing documents. The standard was developed by the OASIS (Organization for the Advancement of Structured Information Standards), and it is free and open format. OpenDocument format supports document representation: A single XML document and as a collection of several subdocuments within a package.
Microsoft Office 2007 Microsoft Office 2010 OpenOffice Calc
Microsoft Excel is a commercial spreadsheet application written and distributed by Microsoft for Microsoft Windows and Mac OS X. Pre-2007 versions of Excel use XLS as the primary format for saving files. It features calculation, graphing tools, pivot tables, and a macro programming language called Visual Basic for Applications. It has been a very widely applied spreadsheet for these platforms, especially since version 5 in 1993, and it has almost completely replaced Lotus 1-2-3 as the industry standard for spreadsheets. Excel forms part of Microsoft Office. The current versions are 2010 for Microsoft Windows and 2011 for Mac OS X.
Microsoft Excel up until 2007 version used a proprietary binary file format called Binary Interchange File Format (BIFF) as its primary format. Used as the basis for XLS files it is a persistence format that supports authoring and manipulating content in workbooks and workbook templates. Most versions of Microsoft Excel can read CSV, DBF, SYLK, DIF, and other legacy formats.