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
PDF is a file format developed by Adobe Systems for representing documents in a manner that is separate from the original operating system, application or hardware from where it was originally created. A PDF file can be any length, contain any number of fonts and images and is designed to enable the creation and transfer of printer-ready output.
Each PDF file encapsulates a complete description of a 2D document (and, with the advent of Acrobat 3D, embedded 3D documents) that includes the text, fonts, images and 2D vector graphics that compose the document. They do not encode information that is specific to the application software, hardware, or operating system used to create or view the document.