Humans interact with Machines

 Last update: 2003/08/08

Devising methods to interact with machines and the very act of interacting with them are often endeavours with varying degrees of challenge. Playing a musical instrument may require years of practice, while setting the time on a mechanical wristwatch is rather straightforward. Doing the same on a digital wristwatch may not be straightforward while changing a program on a TV set is easy, even though setting the programs for the first time may be a challenge. For some reasons the act of programming the recording time on a VCR has achieved the level of emblem in user unfriendliness. 

Early computers had extremely primitive forms of Human-Machine Interaction (HMI). The first peripherals attached to computers were those needed to input and output data, possibly in the form of programs: paper tape, card readers, teletypewriters and line printers. More primitive forms of interaction were also used. To boot one of the early Digital Equipment PDP-11 minicomputers, still used at CSELT in the mid 1970s, required the manual introduction, through switches, of a basic sequence of instructions. 

At that time interaction with computers had already considerably improved and was based on a very simple Command Line Interface (CLI). On the PDP-11, the RSX OS had a simple command line structure: a 3-letter code to indicate the function (e.g. PIP - Peripheral Interchange Program, to move files from one device to another) was followed by a sequence of characters specific to the particular function invoked with the first 3 letters. But with CPU power increasing in the 1960s and early 1970s, research began to consider new ways to reduce the time it took to enter data and reduce typing errors. The airline reservation systems, the earliest mainframe query protocols still in use, were developed during that period of time with the purpose of stuffing as much information as possible into the most compact command. 

In the middle to late 1970s, the microcomputer caused a drop in price of computing power and the consequent popularisation of computing that later materialised in the PC. So research was started on the "next generation" of computers because moving interaction with computers from the "vestals" model, to the "anybody does what he likes with his PC" model, did require substantial changes. 

The most notable interface research was carried out at the Xerox Palo Alto Research Center (PARC), where the first operational Alto computer was completed in 1973. The Alto was the first system equipped with all the elements of the modern Graphical User Interface (GUI): 3-button mouse, bit-mapped display and the use of graphical windows. 

The development of Alto was driven by the desire to provide a more effective HMI by making the computer communicate in ways more congenial to the brain. Cognitive psychology suggested that the part of the brain handling visual stimuli could more effectively track visual elements with a graphic content - called icons, a constant in today's HMI.  Information was organised in patterns that the eye could track more easily by drawing attention to the work in progress. It is an obvious observation that icons could be better processed than characters in a command line, if one thinks that characters represent a highly structured form of information that potentially requires sophisticated, although also highly specialised, processing by the brain. The famous What You See Is What You Get (WYSIWYG) model was so developed.

It took 8 years (1981) for Xerox to introduce the Star, the commercial version of the Alto computer. The Star interface added the concept of the desktop metaphor, overlapping and resizable windows, double-clickable icons, dialog boxes and a monochrome display with a resolution of 1024*768, virtually everything that we see today on our PC monitor, save for colour. 

Xerox was unable to commercially exploit their innovative development, but Apple Computer really benefitted from the new HMI, because Xerox allowed Apple to take elements of the Star interface in exchange for Apple stock. The first computer with the new HMI - Lisa - was released in 1983 but flopped and was followed by the Macintosh the following year, a success that continues to this day. For several years Apple spent millions USD to enhance the Macintosh GUI, a commitment that paid off in the late 1980s when the professional market boomed and Apple's GUI became an emblem of the new world of personal computing and was widely praised by artists, writers, and publishers and, for some time in the early 1990s, Apple was the biggest PC manufacturer.  The consistent implementation of user interfaces across applications is another reason for the success of the Macintosh. 

Compared with what was brewing at Xerox and Apple, the IBM PC running MS-DOS had a cryptic CLI, but things were evolving. Already in 1983 some application programs like Visi On by Visi Corp, the company that had developed the epoch-marking Visicalc, had already added an integrated graphical software environment. In 1984 Digital Research announced its GEM icon/desktop user interface for MS-DOS, with just two unmovable, non-resizable windows for file browsing, a crippled version of its original development probably because the company feared a law suit by Apple.

In the second half of the 1980s, Microsoft embarked on the development of a new OS with a different GUI but for some time also cooperated with IBM in the development of their new OS, called OS/2, that IBM hoped would be generally adopted for PCs. Later, however, the partnership soured and Microsoft went it alone with Windows. At first this was simply a special application program running on top of MS-DOS, which made available different graphic shells running on top of MS-DOS and providing such features as GUI and single-user multitasking. Digital Research's fears proved well founded and Apple did sue Microsoft about the use of its GUI but Microsoft successfully resisted. 

A similar process happened with UNIX. Like MS-DOS, UNIX has an obscure CLI inherited from mainframes. In the 1980s UNIX GUI shells were developed by consortia of workstation manufacturers to make their systems easier to use. The principal GUIs were Solaris by Sun Microsystems and Motif by Open Software Foundation (OSF). 

With computers taking on many more forms than the traditional workstation or the PC, the HMI is becoming more and more crucial. One major case is provided by mobile handsets where the reduced size of the device puts more constraints on the ability of humans to interact with the range of new services that are planned for the next generation of mobile communication. Nokia has developed S60, designed to provide a natural way for users to interact with the limited real estate offered by mobile handsets. Other manufacturers have carried out similar developments.

It is now a quarter of a century since the GUI paradigm was first applied, and its use is now ubiquitous. There are talks about new forms of interfacing, like interacting with the computer via voice commands. At the moment the application of the technology is rather primitive, as it is often just repurposing the visual menu with its audio equivalent, like accessing services via the telephone, or constrained to special environments like people with disabilities. 

Copyright © 2003 chiariglione.org