The struggle over analog and digital computers is analogous to another familiar conceptual struggle, that between the art and science of medicine our subjective sense of a patient s illness and the objective measurements of medical science. Physicians move back and forth between these two realms, and in the process they digitize the world, breaking continuous variation into sections by categorization. Most of our work in medicine is an attempt to translate the continuous variation between health and disease into a digital yes or no decision. The digital revolution is based on the discovery that all forms of information visual images, sounds, symbols and ideas can be easily represented, stored, transmitted and manipulated using the same underlying data system composed of a defined sequence of bits. The central doctrine of digitization is that given a large enough scale of discrete values, we can mimic the continuous nature of the world to such an extent that most observers will not be able to tell the difference between the representation and reality.
All computer files are digital, but there are two different types of digital document files.
In the first, a standard text file, each individual character in the text is represented by a single byte in the computer. Since an average double-spaced, typewritten page contains approximately 2,000 characters, it can be stored in a computer file containing an equal number of bytes. Most word processors use standard text files and add information to the file to specify formatting such as typeface, tab settings and page margins. Every computer has a code table in its memory that quickly translates each of the 256 values into a standard pattern of many dots that are displayed on the computer screen or printed on paper to reproduce the character. The process is quite economical because only the symbol for each character has to be stored in the file.