John Von Neumann (1903-57), was a Hungarian-American mathematician was recognized as the best math student in Hungary in 1921. In 1925, he received his bachelor's degree in chemical engineering from the Swiss Federal Institute of Technology (Technische Hochschule) in Zurich, and in 1926, he completed his doctoral degree in mathematics at the University of Budapest. He grew from a child prodigy to one of the most renowned mathematicians of his time in his mid- twenties, and a man who revolutionized the world of computers.
In late 1943, Von Neumann was invited to work alongside J. Robert Oppenheimer on the "Manhattan Project", being an expert on non-linear physics of hydrodynamics and shock waves.
A man known for his ocean of wisdom, he had great contributions in the field of mathematics (mathematical logic, measure theory, function analysis, ergodic theory), physics (quantum physics, hydrodynamics, ballistics, nuclear physics), economics (game theory), computing (Von Neumann's architecture, numeral meteorology, linear computing, stochastic computing) and statistics.
(ref: Von Neumann in the 40s)
Von Neumann published over 150 papers; 60 is pure mathematics, 60 in applied mathematics, 20 in physics and the remainder on non-mathematical subject, with his last work being an unfinished manuscript being published in the book Computer and the Brain.
now, the people who have been kind enough to read uptil now would be confused: Why is he so important?
that's where VON NEUMANN"S ARCHITECTURE comes in
VON NEUMANN'S ARCHITECTURE:
The history of computers classifies it into two types:
1) Fixed Program 2) Stored Program
Modern programs are based on this stored program concept, as introduced by the man in discussion. Iin this stored program concept, programs and data are stored in a separate unit called memories and treated the same.
The above figure represents his 'architecture'.
It is also known as ISA (Instruction Set Architecture) and consists of the following:
*Central Processing Unit *Main Memory Unit *Input/Output device
Central Processing Unit (CPU):
Defined as it is an electrical circuit, it consists of the following major components:
- Control Unit (CU): it handles all processor signals. It directs all input and output flow, fetches fetches all code for instructions and controls how data moves around the system
- Arithmetic and Logic Unit (ALU): is that part of the CPU that handles all calculations may require: additions, subtractions, comparisons. It performs logical operations, Bit Shifting Operations and Arithmetic Operations.
- Variety of Registers : refer to high speed storage areas. The data processed by the CPU are fetched from the registers. There are different types of registers used:
a) Accumulator: stores the results of the calculations made by the ALU. It holds the intermediate
of arithmetic and logical operations.
b) Program Counter: keeps track of the memory location of the next instructions to be dealt with.
c) Memory Address Register: stores the memory location of instructions that need to be fetched.
d) Memory Data Register: stores instructions fetched from memory or any such data that need to be transferred or stored in memory.
e) Current Instruction Register: stores the most recently fetched instructions while it is to be fetched for coding and execution.
f) Instruction Buffer Register: instruction that is not to be executed immediately is placed here.
BUSES: Data is transmitted from one part to another, connecting all major internal components to the CPU and memory, by means of buses.
1) Data Bus: carries data among the memory unit, the I/O devices.
2) Address Bus: carries the address of data (not actual) between memory and processor
3) Control Bus: carries control commands from the CPU in order to control and coordinate all activities within the computer.
INPUT/OUTPUT DEVICES:
Program or data is read into the memory from the input devices (such as keyboard, scanner) under the control of CPU input instruction. Output devices ( printers) are used to output whatever information is required from the computer.
VON NEUMANN'S BOTTLENECK:
Despite our efforts to enhance performance, it cannot be overlooked that instructions need to be carried out sequentially one at a time. Both these factors hold back the competence of a CPU. This phenomenon is commonly termed as the "Von Neumann's bottleneck". We can provide a Von Neumann processor with more cache, RAM (Read Access Memory) or faster components but if original gains are to be made in terms of CPU performance then an influential inspection needs to be taken place.
This architecture is of high significance and used in our Pcs and even SUPER COMPUTERS.
Links used for the above stated information:
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