Increasing Functional Specificity over Increasingly Commoditized Hardware - Guide to Cloud Computing for Business and Technology Managers - page 12

The Mauchly-Eckert-von Neumann concept of the stored pro-
gram computer used the basic technical idea that a binary num-
ber system could be directly mapped to the two physical states
of a flip-flop electronic circuit. In this circuit, the logical concept
of the binary unit “1” could be interpreted as the on (or conducting
state) and the binary unit “0” could be interpreted as the off (or not
conducting state) of the electric circuit. In this way, the functional con-
cept of numbers (written on the binary base) could be directly mapped
into the physical states (physical morphology) of a set of electronic flip-
flop circuits. The number of these circuits together would express how
large a number could be represented. This is what is meant by word
length in the digital computer. Binary numbers must not only encode
data but also the instructions that perform the computational opera-
tions on the data. One of the points of progress in computer technology
has been how long a word length could be built into a computer.
The design of the early computer used a hierarchy of logical opera-
tions. The lowest level of logic was the mapping of a set of bistable
flip-flop circuits to a binary number system. A next step-up had circuits
mapped to a Boolean logic (AND, OR, NOT circuits). A next step-up
had these Boolean logic circuits connected together for arithmetic oper-
ations (such as add and subtract, multiply and divide). Computational
instructions were then encoded as sequences of Boolean logic opera-
tions and/or arithmetic operations. Finally, at the highest logic level, von
Neumann's stored program concept was expressed as a clocked cycle
of fetching and performing computational instructions on data. This
is now known as a von Neumann computer architecture—sequential
instruction operated as a calculation cycle, timed to an internal clock.
The modern computer has four hierarchical levels of schematic logics
mapped to physical morphologies (forms and processes) of transistor
circuits:
1. Binary numbers mapped to bistable electronic circuits
2. Boolean logic operations mapped to electronic circuits of
bistable circuits
3. Mathematical basic operations mapped (through Boolean con-
structions) to electronic circuits
4. Program instructions mapped sequentially into temporary
electronic circuits (of Boolean and/or arithmetic instructions)
1.3.1 Types of Computer Systems
Today's computer systems come in a variety of sizes, shapes, and comput-
ing capabilities. The Apollo 11 spacecraft that enabled landing men on the
moon and returning them safely to earth was equipped with a computer