Information Technology Reference
In-Depth Information
2.1.2 Some Details: von Neumann Paradigm
and Its Implementation
The von Neumann paradigm encompasses six main principles:
1. Computers built on electronic elements should work in the binary rather than in
the decimal system.
2. The program must be located in a storage device with sufficient capacity and
appropriate read/write speed for commands of the program.
3. The program and the numbers with which the machine operates are represented
in binary code. Thus, in terms of representation, commands and numbers are of
the same type. This leads to the following important consequences:
Intermediate results of calculations, constants, and other numbers may be
stored in the same storage device as the program.
Numerical notation of the program code allows the machine to perform
operations on values that serve to encode program instructions.
4. The challenge of physical implementation of a mass storage device with a speed
of operation corresponding to the performance of logic circuits requires a
hierarchical organization of the memory.
5. Arithmetic units of the machine are constructed on the basis of circuits that
perform the operation of addition. Implementing specialized devices for other
operations is impractical.
6. The machine uses the principle of parallel operation on words, executed simul-
taneously over all bits. At the same time execution of program instructions
(computer operations) is performed sequentially, one after another.
Today's computer technology is very diverse (Fig.
2.4
). It includes digital
computers in which program instructions, input data for solving problems, and
computational results are recorded in memory as sets of binary characters. It also
includes analog devices, processing continuous sequences of values of some phys-
ical quantity. Furthermore, specialized devices for mass solutions of a single task or
a group of similar tasks also exist. However, the overwhelming majority of com-
Fig. 2.4 Main directions of computer technology
