Since 1975, there have been numerous advances in human-computer interface usability-some small, some large. Some of these advances have been physical creations, such as hardware that has improved usability, while others have been software implementations. It is easy to take for granted the level of human-computer usability we take advantage of today. However, even as recent as 25 years ago, the level of usability was much less than it is today. The advances that have occurred in the past 25 years have significantly altered the paradigm of human-computer interactivity. There are, however, five advances or improvements that have made a significant impact: the Visual Display Model, the Graphical User Interface, the WYSIWYG (What You See Is What You Get) paradigm, the WIMP (windows, icons, menus and pointers) interface, and the World Wide Web.
In 1975, human-computer interface usability took some of its first steps into improvement with the development of the first Visual Display Model prototype (VDM). The VDM prototype, designed by Lee Felsenstein, marked the first implementation of a memory-mapped alphanumeric video display for personal computers. Introduced at the Altair Convention in Albuquerque in March 1976, the visual display module allowed use of personal computers for interactive games. The memory-mapped I/O display allowed each pixel or text character to derive its data from a specific memory byte or bytes. The instant the memory is updated by software, the screen displays the new data. This is an important development because, without it, many developments that followed would not have been possible. Before the VDM, computers only had the ability to display text on the screen in a linear fashion. The VDM allowed manipulation at variable screen locations, thus making possible developments such as the Graphical User Interface.
In 1983, the first personal computer with its own Graphical User Interface (GUI), the Apple Lisa, was produced. Unfortunately, its high price ($10,000) did not allow it to become very successful. Undaunted, Apple produced the Macintosh in 1984, another personal computer with GUI, but at a much more affordable price ($2,500). The Lisa failure was also due to its lack of software, so Apple decided to develop Mac Toolbox, which would allow third-party companies to produce software for the Macintosh using the Macintosh interface guidelines. In this way, third party software would be written in a similar style to in-house software, thus promoting ease of use through familiarity. The applications that came with the Macintosh were brilliant for their time. This was the first time a mass audience had seen a GUI in action and a program like MacPaint drag and select shapes, etc. The GUI was a big step toward making computers user-friendly to the general population. As long as the user-system dialog remained largely unidirectional - as it does in a command line interface - computing was going to stay within the minority population of the more technically inclined. In a standard command line interface, feedback on the results of previous interactions is not generted automatically. The user has to know that they have to ask for feedback. Additionally, they also have to know how to ask for it. Every input expression from the user is not accompanied by an output expression that reveals an underlying change in the internal state of the system. Rapid visual and audio feedback on a high-resolution display screen or through a high-quality sound system make it possible to provide immediate evaluative information for every executed user action. This rapid feedback is a feature of the interaction technique known as direct manipulation. Ben Shneiderman is attributed with coining this phrase in 1982 to describe the appeal of graphics-based interactive systems such as Sketchpad and the Xerox Alto and Star. A direct manipulation interface strives to support the following characteristics:
As an extension of the idea behind direct manipulation, the WYSIWYG paradigm was created. In the mid-seventies, Xerox had a research facility at Palo Alto. One of the main researchers at this facility was Alan Kay. He dreamed of a device that looked like a book that you could touch and different information would appear on the screen. The researchers then went on to design a WYSIWYG Word Processor through the use of bitmapping and released on a small scale a computer called the Alto. Included was this WYSIWYG Word Processor, which they called Gypsy. The Alto impressed people that saw it, but as with the Apple Lisa, it was never a success. The cost of the memory alone for the computer was $7000. Although the product itself was a financial failure, it helped bring to popularity the WYSIWYG (What You See Is What You Get) paradigm. This means that what the user sees on a display screen is not the actual document that will be produced in the end. Rather, it is a representation or rendering of what that final document will look like. The implication with a WYSISWYG interface is that the difference between the representation and the final product is so minimal that the user is easily able to visualize the final product from the computer's representation. It is this simplicity and immediacy of the mapping between representation and final product that is significant.
Another development rose to popularity with the production of the 8010 Star Information System, the WIMP interface, which stands for windows, icons, menus and pointers. This interface physically separates the presentation of the different logical threads of user-computer conversation on the display device. The window is the commonly-used mechanism associated with these physically and logically separate display spaces. This concept is very useful for human-computer interaction because when a human is attempting to accomplish one piece of work, they frequently interrupt their current train of thought to pursue some other related piece of work. A personal computer system which forces the user to progress in order through all of the tasks needed to achieve some objective, from beginning to end without any diversions, does not correspond to a human being's working pattern. The WIMP interface allows these diversions by placing each task in its own window and allowing the user to switch between them at will. Generally, computer systems must react to stimuli provided by the user, so they are quite amenable to a wandering dialog that is instigated by the user. As the user engages in more than one plan of activity over a stretch of time, it may become difficult for him to maintain the status of the overlapping threads of activity. A user is able to distinguish between each of these threads by forcing the computer to present the context of each thread of dialog.
Tim Berners-Lee conceived the World Wide Web project in 1989 at the European Particle Physics lab at Geneva. It is important to make a distinction between the Internet and the World Wide Web. Although the terms are used in the general public interchangeably, they are actually different entities. The Internet is made of the software, which connects the network of computers together throughout the world and allows them to communicate with each other through the use of TCP/IP. The World Wide Web, on the other hand, is the graphical interface that allows users to easily communicate across the Internet, while hiding the complex software that runs it. Although the Internet had been in use since its inception in 1969, it had been used exclusively by researchers as a way for them to quickly communicate their findings from experiments with each other. It was not until 1993, when the first set of graphical interfaces (browsers) were invented to communicate across the Web, that the Internet began to be used by the general public. These browsers allow users to access multimedia information easily, using only a mouse to point and click. The integration of computation and communication is transparent to users. In addition, the language used to create these multimedia documents is relatively simple, opening the opportunity of publishing information to any literate person. Interestingly, the Web did not provide any technological breakthroughs; all the required functionality previously existed, such as transmission protocols, distributed file systems, hypertext and so on. The impact has been due to the ease of use of both the browsers and HTML.