Computer programs such as word processors, spreadsheets, games, etc. are called applications. Applications are separate from the operating system software but must be compatible with it in order to be able to operate, e.g. some applications will only run when Microsoft® Windows is running. Files will only open if they are compatible with the application used. Word Processing applications allow text to be typed, amended, formatted, printed and saved as a file (document), which can be reused at a later date. Spreadsheet applications allow text, numbers and calculations to be entered into a worksheet usually in the form of rows and columns. Spreadsheets allow numbers to be amended and the resulting calculations are updated to take account of the changes, ensuring calculations are always current. Database applications store large quantities of data that can be questioned to display only specific pieces of information. A database contains multiple fields and records. A field is a column of similar data, e.g. containing like information such as date of birth. A record is a collection of associated data, e.g. a row containing entries that relate to an individual person, object, company or stock item, etc. Desktop Publishing (DTP) applications use drawing and graphic design facilities to allow greater control over the layout of pages and the appearance of text and graphics. DTP applications are used rather than word processors to create flyers, posters, cards and newsletters because of the ease of using graphics and text together. Some formatting features within DTP applications can also be found in word processing. Presentation applications allow sophisticated presentations to be created for use as overhead projections, Web pages or as an on‑screen display with the option of incorporating special effects, audio and video clips. Web Browsing applications allow users to access the information on the Internet; to search for, view and download text and images from the vast collection of data which comprises the World Wide Web.