A Virtual Reality Primer

by Dr. Killea Garrity


In the late part of the last century, development of computer power capable of generating visual and auditory images that closely approximated reality in complexity of display and motion led to the coinage of the phrase “virtual reality”. At the time, such forays into perceptive “worlds” were based on external apparati that could generate believable fields of information for visual and auditory interaction. Since human perceptive function is prone towards completeness of stimulus, the anomalies inherent in such an interface were not inhibitive. Visual fields were created using goggles or, in later years, cusps that could display enough information for peripheral and foveal stimuli to allow complex stimulus/response exchanges. Similarly, it was a relatively simple matter to generate auditory stimuli with sufficient detail and accuracy.

The reality generated by such interaction was, however, woefully incomplete when compared to what we experience on a day to day basis. Tactile sensations were impossible to simulate, as were the complex gestalts of motion and position. As mentioned above, human perceptive function can, and did, assume the presence of these stimuli when exposed to the corresponding visual, auditory, and olfactory input. However, the resulting interactive field was thus dependent on the perceiver and the response to such stimuli varied across the human sample.

With the advent of neural inductive technology, the next step in the evolution of complete perceptive simulation took place. Rather than providing stimulus to the perceptive organs themselves, it was now possible to simulate the feedback from these organs at a neural level. The perception of stimulus no longer required the presence of external stimuli. Inductors implanted on the Optic, Olfactory, Auditory, Glosso-pharyngeal, and Trifacial Nerves as well as the spinal cord could simulate 94% of normal human perceptive function.

This technological revolution shifted the limiting factor from stimulative mechanism to input field production. Generating movement and tactile images of sufficient detail requires incredible computer power. A typical nerve space (total volume of information encompassed by a neural channel) contains a million pieces of information and requires refresh every 500th of a second. In the case of spinal stimuli, the space complexity quickly approaches several million variables. The total input space for human normal perceptive field simulation averages 5 million variables refreshed 500 times a second for a total data flow of about 2.5 gigabytes/second. Common terminology measures this in terms of pulses, the fiber optic instantaneous bandwidth of 1 thousand bytes, so a single second of human perceptive space takes up 2.5 megapulses. Since generation of each variable requires an average of 100,000 computer operations, a single second of stimulus space requires 250 trillion operations. Computers capable of this kind of processing were not widely available until the advent of inline molecular superconductors. Even then, the machines were incredibly expensive.

Most current high-grade systems require intrusive surgical modifications, or ‘wires’. The operation is mundane, but does require extensive manipulation in the cerebrum. For this reason, it is not considered simple. As mentioned above, a typical wire harness attaches to five of the major nerve bundles coming from the brain as well as the spinal cord. Current induction systems are quite small and can be virtually undetectable. The feed for the system usually exits at the base of the skull, but routing to the wrist is not uncommon. This does, however, require a booster in the shoulder area. Feeds can be anywhere, but must attach to bone to provide sufficient stability for ‘jacking’. It is also possible to hide the feed just below the skin and use induction pads for contact, but this kind of jack will not work with most systems and cannot deliver the kind of response some applications require (typically computer and control systems).

Civilian systems often use much less responsive and intrusive systems for entertainment. Simulated stimulus systems (simstims) usually come with external inductors for the eyes, ears, nose, and spine. The units look like a complicated pair of headphones. The effect of the system is much less intense, but still very believable. Since these systems are typically 40% less effective than intrusive delivery mechanisms, they are not adequate for most high-end applications. They are, however, very popular in the consumer market.

Contrary to popular opinion, it is unnecessary to use a keyboard when operating through a neural harness. Once the user is “jacked in”, they can communicate with their system without any physical effeort. In fact, since a wire must completely pirate any stimuli passing along it’s client nerve, stimulus from the body is blocked both ways. It would prove disastrous if a vehicle operator, or “rigger”, were to actually move her body while controlling her machine. The unguided motions would undoubtedly result in injury. For this reason, a person working with a wire is unaware of stimulus from their body and cannot control it in any way. Usually, wire control systems monitor stimuli for neural flags and then pass similiar stimuli along to the user for action. Such things as excessive pain, or maintenance signals are mimicked in the current virtual reality so that the user knows they are in pain or need to visit the restroom. Disconnection from the system is a simple matter of will without a physical manifestation. “Jacking out”, portrayed in so many vids as a violent unplugging of the wire jack, is in fact a completely mental process. The actual unplugging is only manipulating dead wires that no longer carry a signal.

>>>[So would it be possible for ice to block the ‘jacking out’ signal, or intercept it and let deckers think they jacked out?]<<<
—Micromara (14:20:49/05-31-52)

>>>[Yes to both. It is possible to take control of the simsense of a deck externally and generate alternate feedback. It would take serious computer power, some really artfull programming and the right context, but it is possible. You would THINK you fought off that ice. You would THINK you were safe. You would THINK anything it wanted. Until they came and got you.]<<<
—Guru (08:45:23/6-2-52)


Confusion between simstims and virtual reality units are common. Simstim playback units are exactly that, players. They are in no way capable of true interaction. Consequently, they do not constitute a true virtual reality. The user is an observer only. As mentioned above, robust perceptive space virtual reality requires in excess of 200 trillion operations per second. Only the more expensive civilian units can deliver this kind of performance. In addition, these units require special hardware and software designs completely different from what one will find in the normal computer. Finally, all of these units assume the user is ‘wired’ and consequently they appeal to only a small segment of the market. Thus, though there are probably 200 companies that produce computing engines in North America, there are only five that make these “cyberdecks”, though one can modify an existing computing engine with available (if expensive) parts.

The level of virtual complexity these cyberdecks allow varies. The Tandy (Radio Shack) and Amiga (CBM/Target) machines are aimed at the low end of the market and though they are by far the most popular models, they also deliver a significantly curtailed reality. Sounds are muted, visuals less detailed, motion sloppy, and reaction sometimes sluggish. They are also prone to malfunction and breakdown. They are true virtual reality machines, but it is obvious to anyone using them that they are in a simulation. The top of the line models from Fuchi, Fairlight, and Interface are capable of stimulus impossible to differentiate from reality. These units carry, however, commensurately high price tags.

>>>[Have deckers ever been caused to forget they were in cyberspace?]<<<
—Micromara (14:22:39/05-31-52)

>>>[See above. Ice that good could make you believe you had jacked out and were sitting around with your SoyCaf while it was tracking your inert, jacked-in body down.]<<<
—Guru (08:49:23/6-2-52)

>>>[What Guru neglects to mention in both places is that the program doing the simulating would have to know what your pad looked like to simulate it. Remember that a wire does not constitute a conduit to your thoughts, only a stimulus/response channel. Thus, in the situation Guru suggests above, there is no way the ICE (or whatever) could simulate your apartment/house/drainage ditch unless someone fed in the details.]<<<
—Thor (09:54:5/6-24-52)

>>>[It is interesting to note that cyberdecks have a great deal in common with simsense units in terms of interface. Not too surprisingly, they can cause many of the same problems simsense abuse causes (i.e. multiple personalities, catatonia, mania, and even synesthesia.)]<<<
—Cyberdoc (16:08:41/6-12-52)

The Matrix

Current urban mythology (aided by the popular media) paints a romantic but innacurate picture of the current global data network, commonly refered to as the ‘matrix’. The matrix is not one huge network, but a collection of networks, each of which has its own peculiarities as well as a distinct flavor. Though the UMS imparts a degree of standardization to the sensory space, it is by no means universally accepted or implemented. In many cases, older systems are not capable of the necessary stimulus sophistication and thus implement simpler realities.

In some cases, the UMS has been almost completely ignored in favor of asthetic expression. Such ‘sculpted’ systems are expensive, but exist in sufficient quantities to warrant mention. It is interesting to note that such systems cannot be displayed on some of the more common decks available (i.e. the low end Tandy and Amiga offerings) because the systems cannot process the necessary information spaces. When accessed by such a deck, the stimulus is downsampled (’damped’) to allow interaction. Though this does not usually result in functional limitations, it can limit the user if the designers do not take such damping into consideration. The upshot of this varied representation is that the matrix appears not as a single reality, but as many realities joined by a variably consistant transport metaphor. Communications grids in most parts of the world are UMS compliant, but there are many exceptions.

Another common set of myths surrounds the degree to which experiences in the matrix can have physical ramifications. The burning deck meltdown so popular in corporate sponsored propaganda stims and vids is simply not possible. The connections prevalent throughout the process are not capable of carrying those kind of voltages. This does not, however, render the concept of interface induced damage unreal. It is simply much less obvious to the casual observer. The human nervous system is a fragile and sensitive electro-chemical system which, when hooked directly into a stimulus space, becomes incredibly vulnerable. Because the nature of the stimulus space is so complex, filtering that space requires huge amounts of processing power. System designers, trying to achieve the best interface for the least money, use only the most rudimentary safeguards; voltage and volume monitors that are relatively ‘stupid.’ For most users, this is not a significant drawback as the stimuli commonly available is far below that required to cause significant damage. After all, who would use the system if neural damage was a commonplace occurance?

However, illegal use of interface equipment can result in physical damage to the nervous system. Simstim units are often modified to allow the use of excessively high levels of stimulus. So called ‘Better than life’ or BTL systems are a mainstay of the black market. Repeated use of such systems results in a variety of neuralogical disfunctions, some of which are fatal.

Similiarly, cyberdeck interfaces are capable of carrying damaging and even lethal signal levels to the nervous system of their users. The generation of such signals is illegal, but if the recipient is involved in an illegal access, the situation is not black and white. Court cases involving such instances have established the ‘home defense’ precedent now recognized by most courts. A SAN is sufficient notice to any user that the territory they are experiencing ‘belongs’ to someone and that their unwanted presence within that territory constitutes trespassing. In addition, bypassing safeguards to enter a system is now legally classified as breaking and entering. From this standpoint, the use of so called ‘black’ intrusion countermeasures (IC or ice) is analogous to any weapon used to defend one’s property.

It is possible to install filters which can recognize such stimuli and counter them. The hardware for this would have to be roughly twice as fast as an unfiltered deck. This kind of speed upgrade usually carries with it a tenfold price increase. To build such a system with the throughput of say a Fairlight Excalibur would cost in excess of 50 million nuyen. In addition, the advantages of such a system are questionable since illegal system access requires negation of protective ice in addition to survival and extended combat usually results in disconnection or ‘dumping’.

>>>[A toaster tech friend of my mine scoffed at the idea of “meltdown” and pointed out that the switch necessary to keep out any large voltage was a .25 nuyen piece of hardware. What gives?]<<<
—Elvis (16:08:41/8-04-52)

>>>[That would be true if in fact a single voltage spike was the problem, but it isn’t that simple. What Garrity is talking about here is a stimulus spike. This is not a single peak on a single line, but a max on every channel coming in, analogous to turning every nerve in your body on at full volume at the same time. No single input is over the edge, but the cumulative effect is a matter of record.]<<<
—Cyberdoc (16:08:41/6-12-52)