Peter Bentley Digital Biology Headline Book Publishing 2001

KEYWORDS : virtual machines - digital universe - digital biology pg 29 Virtual machines are real universes Universes are made according to laws or rules, and a computer program is a set of rules. When a program is run, and the rules are followed by the computer, a digital universe is created. In computer science this is not a new idea. The concept of the digital universe has been known and understood for many years. It has simply had a different name. Traditionally, digital universes have been called virtual machines. The computer program defines a digital universe. A computer executing that program creates that digital universes. This is the essence of software, computer programs and digital universes. Fundamentally, they are all a collection of rules that define the behaviour of the computer. These rules are written down using a high-level language, compiled into a much greater number of low-level instructions, and executed by the rules embedded in the electronic circuits of the computer. Every one of our computers is capable of emulating the behaviour of every other computer (UTM -Universal Turing Machine). When it computer is asked to run such emulation software, it is transformed. It is no longer able to run the software designed for it. The action other keys, the output to the screen, the operation of the mouse - everything has changed. The computer can now run only software designed for the computer it is emulating. Because he emulation software alter the behaviour of the computer in this way, we call it a virtual machine. In general, the virtual machine is a piece of software that defines an environment. That environment may duplicate the behaviour of another physical computer or it may be a distinct environment in its own right - an environment that can be created by different models of computers and provides a consistent interface for other pieces of software. And, with a little stretch of the terminology, we can regard every piece of software as a type of virtual machine. Our operating system defines a clearly identifiable environment, a familiar look and feel, with consistent behaviours in response to your input. pg 33 Digital universes are not simulations. They are not fakes or metaphors. Even their inhabitants are surprisingly similar to us. We saw at the beginning of this chapter that every object in our universe can be broken down into smaller and small pieces, until we found that the smallest bits were points of energy. What are digital objects made from? They are made from binary 1's and 0's, held as patterns of electricity; the flow of electrons. What is an electron? It is the point of energy. So physical object and digital objects on both made from energy. So I think it is time to think a little hard about the capabilities of computers. These machines are not automated slide rules. Our computers are much more than this. They are universe creators. Of course our computers are capable of creating only simple universes compared with the one in which we exist. But computers still have one advantage over our universe. With computers we can define the laws of physics. We can drive software that defines the fundamental movement of bits inside the digital universe. And, if we make our digital universe follow similar rules to those we observe in our universe, we see the emergence of processes, intricately structured objects and complex behaviours that resemble those we see around us. Digital biology blooms.

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