
Writing a data management plan: introduction to file formats
A file format is a way of encoding information within a computer file. A program or application must be able to recognise the file format in order to access data within the file.
For example, a web browser is able to process and display a file in the HTML (hyper-text markup language) file format so that it appears as a Web page. If the browser encounters another filetype, it may need to call on a special plug-in to view it, or it may simply let you download the file to view in another program if it cannot recognise it.
A particular file format is often indicated as part of a file's name by a file name extension, or suffix. Conventionally, the extension follows a period in the filename and contains three or four letters that identify the format (.jpg or .jpeg).
In the Windows operating systems you can choose to display file suffixes or not. ("Hide extensions for known filetypes" is the default option in Windows Explorer, which can be reversed in order to see file extensions.) Macintosh files often do not have a suffix, which can be a problem when copied to another system to use.
Proprietary formats usually must be opened by the software application to which it belongs. Someone without a licence to the application may not be able to open the file at all. Open formats, in which the software company or collective publishes the format rather than keeps it proprietary, are more likely to be rendered by more than one application. Adobe PDF is an example of an open format that may be viewed in a number of applications, not just Adobe products.