File types - proprietary vs. industry standard

When I gave lectures in class on this, there were two distinct groups of files: Proprietary file types were 'secret' types that were owned by software companies and used for 'their' files and difficult to open without 'their' application programs or fancy translator programs. Industry Standard file types were open types that were well defined and any programmer could write code to read and write them. Generally speaking, users used proprietary types to save material that they were working on to maintain as much information as possible. They would then save as an industry standard type to make the files transportable to all systems. So that when working in Photoshop, you saved as a Photoshop file to maintain layers, objects, masks, etc., then saved as a jpeg to put on the web.

This is still true to an extent, but the lines are blurring. The Microsoft Word document type is sufficiently well documented that many different programs can read and write the files. Photoshop files can be read by GIMP, etc. But the user should still think about his/her target audience and how much information is needed in the file. With posting files on the internet, the trade-off of file size versus total information must also be taken into consideration.

In Windows, you can show or hide these extensions by opening a window, then from the Tools menu, select Folder Options, click on the View tab, then select/deselect Hide Extensions for Known File Types. I often leave them hidden for new users, but show them on my account because I use the information to help me tell what is going on.

A list that I gave my students years ago that I expected them to learn (well, there were a couple of new ones):

• Microsoft Office
  • .doc - Microsoft Word; proprietary word processing format. But is now close to an industry standard. Pages (Macintosh), OpenOffice, and other programs can read and write this format.
  • .docx - Microsoft Word (versions 2007 and 2008); similar to .doc, but cannot be read by a number of older programs, including older versions of Word. There are free translators available for Word 2003 and 2004 that open them seamlessly.
  • .xls - Microsoft Excel; proprietary spreadsheet format. Can be read by OpenOffice.
  • .ppt - Microsoft PowerPoint; proprietary format that holds presentation information. Can be read (and created) with OpenOffice. Microsoft also offers a free PowerPoint viewer program.
• Text
  • .txt - the all-time classic text file. It holds nothing but the basic characters of text. It can be read by almost any program on any platform in the computer industry. But it does not hold any formatting or graphical information.
  • .rtf - Rich Text Format. Similar to a text file, it is an industry standard, but it holds basic information on formatting. Fonts, margins, etc.
• Graphics
  • .gif - simple, small, compressed graphic file. Particularly good for object-oriented graphics with basic colors and shapes.
  • .jpg - small, compressed graphic file, used for photo-style pictures.
  • .tif - historically used for high quality graphics (desktop publishing, etc.)
  • .png - standardized graphic format that allows layers and other advanced features. Sometimes used as an internet format.
  • .psd - Photoshop file. Proprietary, but is becoming a high-end industry standard. GIMP is an open-source program that will read Photoshop files.
• Other
  • .htm or .html - web pages. A universal format, but because browsers and computers do things so differently, one must be careful of how it will look on other platforms.
  • .pdf - Adobe Acrobat file. Holds formatting and is difficult to edit.
  • .exe - an actual executable program in the Windows world. I put this in the list because if it comes in an e-mail, it is likely a virus.
  • .vbs - Visual Basic Script. Because it is so easy to program in Visual Basic, this is the first stop for many virus writers. Beware of any that come to you from the internet.

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