The Conventional Interface

Modern computer systems universally use a "graphical user interface." In the early days of "personal computers," it was thought that making the computer look and behave as much like the physical world as possible would make it easier for office workers to move from typewriters and file cabinets to word processors and disk drives. While the transition, for the typical office worker, was made possible, a side effect was that many novice computer users treated word processors as typewriters, and never used the advanced features that would have made their life easier.

One part of this design decision, made in the first widely available graphical computer interface (the Apple Macintosh), was to make the screen look as much like a piece of paper as possible. The original screen of the Mac was 8 1/2 inches wide, the same as a standard piece of paper, and had a screen resolution of 72 pixels per inch. This was important because print "point size" is measured in units of 1/72 of an inch. Thus, on the early Mac, a 12 point font would be displayed at 12 pixels high.

This equivalence of points and pixels remains an assumption of the conventional interface, as seen in the default installation. However, the relationship is not accurate on modern computers. The early IBM and PC Compatible computers used a monitor separate from the computer itself, and with a potentially larger screen. These Windows PCs adopted a "standard" resolution of 96 pixels to the inch rather than the 72 of the early Macintosh. This allowed for slight improvements in smoothing, and took advantage of the enhanced resolution (640x480 pixels) of the Video Graphics Adapter (VGA) monitors that came after the introduction of the Macintosh (512x342 pixels).

With advancing technology over the last decade, the size of monitors has increased, as has the resolution. From a "standard" 14 inch monitor in the early 90s, the expected monitor has expanded in size to be a 17 or 19 inch diagonal. Over half of computer users now have a screen resolution of 1024x768 or greater. A modern 15 inch laptop display may have a screen resolution of 1600x1080 or more! Yet, the display "assumptions" have not changed. The default size of fonts, icons, and other features of the interface today are the same as they were a decade ago.

Note that it is possible, in the Microsoft Windows operating system, to tell the computer to use a screen resolution other than the assumed 96 pixels per inch. However, since parts of the interface are defined in points or inches, and other parts are defined in pixels, this can produce odd distortions of the interface.