Computerized or digital media (from now on we shall call them "new media" for ease of reference) start precisely from the reproduction capacities of traditional technological media, which they expand via specific processes. In fact the new media, in addition to reproducing, have the capacity to produce totally new contents of a synthetic nature; in other words, they generate themselves within the same medium through different processes. If we try to find out where these production capacities come from, we discover the following chain: in the case of images, the "traditional" media are based on the photogram or frame. This constitutes the atom of such media; it is the smallest unit on which work can begin. As we all know, a film or video is nothing more than a linking or sequence of photograms. The new media also work with photograms and sequences, but they start from an earlier point, which is the pixel. The pixel is the visual atom of the new media, on the basis of which we can create photograms, and by manipulating the pixels of each photogram we can create animations.

However, the new media have a very important capacity - the capacity to calculate - and it is this capacity that allows us to create synthetic images from pixels. In a photograph, for example, what appear are light phenomena reproduced on some kind of medium. It is true that we can carry out certain manipulations and "create" images with filters or development techniques; nevertheless, at no time does the camera generate images from a non-physical source. Whereas with the computer we can generate totally fictitious images, which originate from the result of some calculation or algorithm. A mathematical algorithm can be mapped and its results transformed into pixels, giving us the visual representation of an internal process in the machine.

1.1. Computerized or digital media

So the computer as a medium is very suitable for achieving a fusion between reality and fiction, since it allows us to produce and reproduce both images and sound.

As we delve a little deeper into production and reproduction capacities, we can see that "traditional" media allow us to create objects that can be reproduced mechanically, meaning that such objects are disseminated in the form of identical copies, while the new media allow generative reproduction. With this type of reproduction, copies will not be identical, but similar to one another, with variants that adhere to certain basic rules or patterns. In this way, objects created with the new media possess - at least potentially - an inherent polymorphism, something in the way of a "genetic code" that allows them to appear in a different form each time. We shall call this "genetic code" a "system of rules", and it is a fact that a system of rules, explicit or otherwise, is in play behind each of these objects.

.2. Algorythms and rule-based systems

This system of rules, considered as a series of formal instructions marking the development of a piece, gives us the key to go back and analyse the sentence that we used to introduce this first topic. We said that technological devices could be used as tools or as media for creation. What is the difference between a tool and a medium? A tool is a device that we use to create an object existing as an entity separate from the tool. On the other hand, a medium allows us to create "objects" that also exist within the medium itself. A simple example follows: a camera allows us to take photographs that, once printed, exist independently of the camera. We can say that the camera is a tool. On the other hand, a computer allows us to write a code that, each time it is executed, generates a random image based on different algorithms. That image exists within the computer and is a synthetic product generated by the machine. It is true that we can also print the image and show it as an independent object, but this is not essential. We can therefore confirm that, in this case, the computer becomes a medium. It is precisely this use of the computer as a medium that allows us to generate environments and experiments that otherwise could not exist.

1.3. Aesthetical particularities of new media

.4. Aesthetics of New Media: a theoretical approach

Before we begin to delve into the central topics of this text, and then to discuss the creation of interactive environments and physical interfaces, we should mention a number of general aesthetic considerations regarding works created through the new media. We also need to make two brief chronologies, in which we shall be able to appreciate how art, thought and science have been developing, first in parallel and later jointly, until they have become what we now call interactive works. This exercise will be especially useful, since there seems to be a kind of "amnesia" around the computerized media. We rarely stop to think about the history of such media, and we have a tendency to consider them as completely new. Perhaps the reason for this is the very speed with the history of the computerized medium has come about, especially in latter years. Nevertheless, learning how the new media have developed, both conceptually and technologically, will enable us to achieve a more in-depth understanding of them.

As mentioned above, we cannot speak of one unified aesthetic doctrine characterizing works created with new media. We can, however, say that these works are a clear example of how artistic work is moving increasingly towards the intangible and fragmentary. We can also say that certain features common to such works correspond to what is known as the post-modern aesthetic. According to Frederic Jameson, a thinker who provided perhaps one of the profoundest definitions of the aesthetics of post-modern creation, works belonging to this aesthetic (which he calls "texts") do not have a definitive length; they do not have a beginning or an end, unlike a classical work that must be interpreted as a whole in itself.

While we are considering computers as media that make innovative works possible, we need to ask some questions on the nature of such works. What are the aesthetic characteristics of works created with the new media? In general, we can say that there is no unified aesthetic attached to the new media and digital art. Formal manifestations in the area of electronic art are tremendously varied, and can range from environments that simulate, almost to perfection, some aspect or other of our physical reality, to pieces that are calculated and generated entirely by the computer's internal processes. There exist a great variety of formats, such as audiovisual installations, net art, software art, virtual reality and augmented reality, and so on. Nevertheless, we can make a start on understanding works created with the new media by studying the various special features that they have in common:

Interactivity, or the new media's capacity to involve the spectator directly in a work; the fusion of reality and fiction that, as already mentioned, is the fruit of the computer's combined production and reproduction capacities; the fusion of art and science, which occurs naturally in any work of art created with technological media; and a relational capacity that consists in the new media's ability to create pieces where the importance lies not in one isolated object, but in the relations between object systems, between the piece and the spectator, or else between the piece and the environment.

2. Chronology of technique

In the previous topic we talked about how electronic media, both "traditional" (photography, cinema, television and video) and "new" (computer) allow us to create works that exist in a hybrid space in which art and science mingle. We also mentioned how the link between such disciplines was almost considered to be an aberration until the middle of the last century. Well, these considerations lead us to study two separate but parallel chronological developments: on the one hand, the evolution of technology that has led to the existence of the new media as we know them today; and on the other, the evolution of art and thought that has led us to envisage the use of such media to create and produce aesthetic objects. In this topic we shall establish a chronology that begins in the 1940s and concentrates exclusively on providing an overview of the origin and development of the multimedia capacities of computers. We could go further back in time and discuss inventions such as the abacus in Chinese culture, considered to be the most ancient calculator in the history of humanity (around 190 of our era), or the "difference engine" invented by Charles Babbage in 1821. However, that kind of historical review goes beyond the aim of our text, so we shall concentrate on more recent research and inventions that have resulted directly in the audiovisual and interactive capacities of computers.

2.1. Context

The first computers

We shall now talk briefly about computers. The first computer, invented in 1946 and called "ENIAC", was physically accommodated in a room at the University of Pennsylvania . In 1951 the "UNIVAC" computer became the first commercially available model.

From then on the size of computers progressively decreased as their processing capacity increased. We shall see how the true digital "revolution" started at the beginning of the 1980s, a decade during which home computers came onto the scene. It is important to note that, in addition to the evolution of the computer itself, the invention of virtual "environments" also made such a revolution possible.

First, we have the first Graphical User Interface (GUI), developed by Douglas Engelbart, Ivan Sutherland and Alan Kay in Palo Alto , California , in 1970. This "virtual" interface allowed users to interact with computers via visual representations, much more intuitive and direct that the command lines that until then had been the only way of programming a computer or carrying out tasks with it. This graphic interface led, in 1983, to the first commercially available "desktop" operating system in the Macintosh computer.

Secondly, we have the creation and development of computer networks. The forerunner of these networks was the United States Department of Defense's "Arpanet", which was designed to interconnect different nodes or computer terminals without hierarchical relations.

Before we begin, however, we should mention that the greater part of such research and inventions flourished in the context of the North American war industry. This was in the middle of the last century, at a time when the United States was beginning to consolidate its position as the major world power and therefore needed to strengthen its capacity for war. A great deal of energy, both intellectual and economic, was invested to achieve this, and the fruit of this development resulted in many of the computerized capacities that we now use on a daily basis. This brief consideration is not meant as a value judgement on the technology that we use today (we affirm that technology, intrinsically, has neither a positive nor negative value; it is the use made of such technology that generates creativity or suffering). Our aim is simply to create an awareness that will enable us to appreciate more objectively such technology. Let us begin, therefore, by talking about certain personalities now considered to be the "founders" of the computer's multimedia capacities.

We open our technological chronology with Norbert Wiener, since it was in the nineteen-forties that he first introduced the term "cybernetics" for a study area analysing the symbiosis generated between humans and computers. When we come to study definitions of interactivity and interfaces in later topics, it will be very important to bear this term in mind, since we shall use it to qualify certain electronic objects in which the union between humans and machines makes completely new environments and experiences possible.

In that same decade, John Turkey used the word "bit" for the first time to describe binary digits (0 and 1), the basic unit or atom of data stored in a computer.

In 1945, Vannevar Bush published "As we may think", an article in which he proposed "MEMEX" an analog system for information storage and consultation. This system was based on mechanisms that enabled information to be handled on microfilm (a medium still used in libraries, for example, for storing and consulting old newspapers and periodicals). Although "MEMEX" was never physically constructed, it was planned using the metaphor of the desk as a space for work, analysis and information storage. The importance of "MEMEX" lies in the fact that it was a direct forerunner of our current operating systems such as Windows and Macintosh. These systems, like a number of others, are also based on the metaphor of the desk: there are folders for storing files, there is a waste bin, and so on. If we place this development within the context of this text, we can say that such operating systems constitute "virtual" or "digital" interfaces since they allow us, via visual representations on a screen, to interact directly with the computer.

Still on the subject of the computer's visual capacities, we see that in 1962 Ivan Sutherland invented "Sketchpad", the first computer graphics system. The system was composed of a sensitive screen and a "lightpen" using optic technology for drawing directly on the screen. The screen and lightpen together (we could draw a parallel between paper and pencil) constitute another example of a physical interface that, in this case, allows the user to draw. Curiously, Ivan Sutherland was also the inventor, even before the term existed, of the first "virtual reality" helmet (the "Sword of Damocles"). This is an example of how, in many cases, technology precedes theory: initially an interface is built and experimented with, provoking later reflections on the part of researching theorists. It does not always happen like this, but many other examples can be observed in computer technology.

In that same decade, the 1960s, Theodor Nelson first spoke of "hypertext" and "hypermedia", meaning interconnected texts, images and sounds that the user can read (or navigate, if you prefer the term) in multilinear form.

We also find the first applications intended for multimedia, such as Morton Heilig's "Sensorama", which offered a multi-sensory environment to spectators experiencing pre-recorded visual, auditory, olfactory and tactile sensations, or "Space War", developed by Steve Russel of MIT (Massachusetts Institute of Technology), which involved real-time visual interaction and is considered to be the first computer game made with digital graphics.

Out of "Arpanet" came "Ethernet", a system of intercommunicating networks invented by Bob Metcalfe in 1973; the communication protocol TCP/IP (1978), which is used to this day for exchanging information on the Net; and HTTP (1989), the protocol that allows us to create and consult Web pages.

As for physical interfaces, a subject directly connected with this text, we also find significant forerunners, which successfully sought to establish links beyond the purely functional (mouse, keyboard, screen, etc.) between the physical world and the digital domain. We shall mention two of these: 1982 marked the creation of "Skeleton Animation System", the first system for detecting movement via cameras, which enabled a human being's actions to be reproduced in a given space and represented in a 3-D model on the computer screen. That same year the first "Data Glove" was created, which, as its name implies, is a glove that perceives degrees of flex in different articulations of the hand and converts these into digital signals. In "Data Glove" we see the will to involve certain human gestural manifestations more intensely in interaction with the computerized medium.