Each form of computer data can be saved in a wide variety of different data formats (languages). Every program that is able to save data recognizes one or more data format. The favorite data format used by any program is referred to as its "native" format. Simple programs might recognize only one data format. More complex software might recognize many. Often these formats are proprietary, meaning that they are the legal property of the company that publishes the program that created them. Such data is often recognizable only by the program that created it (or other products written by the same company). In some cases, one company will arrange a contract allowing them to use another company's data format in exchange for royalties or other value.
A few data formats have been developed and placed into the public domain to allow easy (low cost) transfer of data between competitive brands or types of software. Some examples of these are:
| Data Type | Filename Extension |
Data Format (Language) |
|---|---|---|
| Documents | rtf | Rich Text Format (Word Processor Document Language) |
| Plain Text | asc or txt | American Standard Code for Information Interchange (ASCII) |
| Graphics/Images | jpg or jpeg | Joint Photographic Experts Group (Image Language) |
| Web Pages | htm or html | HyperText Markup Language (Web Page Source Code) |
An important distinction exists between the data types "document" and "plain text" (or just "text"). Document languages can store data about the appearance and layout of a document. Plain text cannot. The only data that plain text can save is information about which characters are being stored, but nothing about their appearance such as boldfacing, underlining, typeface, size, etc. Nor can plain text store any information about document margins, page numbering, headers, footers, or any embedded data such as images.
"Documents" contain complex data representing (among other things): characters and information about their appearance (typeface, type style, type size, color, etc.), page layout (margins, headers, footers, numbering schemes, etc.), paragraph layout (indentation styles, tab positions), and much more. The common language for plain text does not have the ability to represent any of these things. So if you want to store such information, you will have to use a proprietary language belonging to a specific company or find a common non-proprietary data format that is complex enough to store the complex information within documents. Word processing programs use their own native proprietary language when saving documents on a disk, but most of these programs also offer the option of using common non-native data formats. Some of these are non-proprietary; others are the proprietary data format of another company (assuming a contractual arrangement has been made).
The following steps provide an example of how to save a document in a common non-proprietary data format while using the Microsoft Word brand of word processing software. They were written under the assumption that you have completed typing the document in memory using Word and are now ready to save it.
Files saved this way will be stored on disk with a filename extension of "rtf". Most word processing programs have the ability to open and interpret such files. With some brands of software, you might find it necessary to select the "Rich Text Format (*.rtf)" file type using the "File of type" drop-list in the Open dialog box before you will see the filename listed.
Often when a program is revised, the language that it uses to record data is also enhanced. Typically, a newer version of a program can read data saved by an earlier version, but the opposite is not often true. So, if you have an early (old) version of Microsoft Office on a computer at home and you want to save a document in one of our college classrooms which uses a more modern version of the program, you will have to save the document in the older data format if you plan to open it at home.
The following steps provide an example of how to save a document in an earlier data format than the one normally used by Microsoft Word. They were written under the assumption that you have completed typing the document in memory using Word and are now ready to save it.
The following steps provide an example of how to save a document in the simple and widely known non-proprietary data format known as "ASCII Text". The weakness of this approach is that the ASCII Text language has severe limitations in its ability to represent the data normally contained within a document. All graphic information about appearance and layout will be lost in the translation from the complex (DOC) proprietary format into the simple TXT format. The only thing that will be retained is information about which characters were in the file and what order they were typed. The instructions below were written under the assumption that you have completed typing the document in memory using Word and are now ready to save it.
Files saved this way will be stored on disk with a filename extension of "txt". All word processing programs have the ability to open and interpret such files. With some brands of software, you might find it necessary to select the "Plain Text (*.txt)" file type using the "File of type" drop-list in the Open dialog box before you will see the filename listed.
Similar techniques to those above exist for converting other types of data (graphics, audio, etc.) between native and non-native data formats for given software. Most of them use the same approach of simply selecting the alternative data formats from within a "Save as" dialog box. Take a look in your favorite program to see if it offers alternative data formats.