It became possible in the ancient calculators of 1940s
To solve long and tedious mathematical problems
In a systematic way and in a billionth of a second
Only after “programmable memory” was introduced.
By Dr von Neumann’s team
Even in the decades before Dr von Neumann’s time
The jumble of logic circuits did mathematics no doubt.
Addition and subtraction
Multiplication and division were all done
Using the “accumulator” logic.
But the human engineer had to sit
Before the jumble of logic circuits all time.
The human engineer had to send in numbers
In the 010101 code in a most tedious way .
Perhaps he was often confused with the maze of circuits
And endless rows of zeroes and ones.).
Dr von Neumann stepped in and dispensed with this tedious way.
He decided that just as a class room has a black board
For the teacher to write the detailed working steps
Of the tough algebra problems
A similar “memory board” is required right inside the computer
(Here the word “memory” means only a blackboard
And not the human brain’s capacity to remember.)
Dr Neumann loaded on the memory board
A series of “instructions” in standardized 010101code
For the CPU to follow to solve the problem.
The “instructions” also contained particulars
Of mathematical circuits to be operated by CPU
To make the arithmetic unit to do the toughest mathematics.
To start work the CPU obtained
Copy of each instruction from main memory
Through the computer’s super high ways
With eight / sixteen/twenty/forty lanes.
The very important parts called registers
Contained inside the CPU helped it
In a most efficient way to analyze each instruction
And do the switching of mathematical circuits
And to obtain numbers from the memory houses
And send them to alu to do the computation
By the accumulator principle which is very basic to the ALU.
To write a well knit group of instructions
(Called by people nowadays as a “computer program”)
Creation of the electronic “memory board”
Right inside computer was a must.
At that distant time of 1940s
The “memory board” was made of extremely tiny magnetic rings
Arranged in rows and columns perhaps on a plastic sheet
It was like a city of tens of thousands of tiny magnetic houses
Each magnetic house was made by interconnecting
Eight or sixteen chambers
To hold the eight or sixteen zeroes and ones.
The few dozen instructions together constituted
Working steps to solve a mathematical problem
And were collectively called a “computer program”
And this arrangement is called “programmable memory”
The memory board inside computer
Was known by technical name “main memory”
By using this principle the ALU could manage
The entire computing work without assistance of human engineer.
Since the human engineer’s instructions
Were already given in the program
His assistance was not much required.
He gave only an occasional nod or occasional frown
And toggled one or two keys on the key board and that was all
The CPU has to implement the “instructions”
One after the other to solve the “program”
The instructions are not like lines
From the poetic and dramatic works
OfShakespeare or Keats.
“A rose is a rose by whatever name you call it”
“A thing of beauty is a joy forever”
Such sentences can not be found
In “instructions” given to the CPU.
The instructions are like military commands.
A sample I give below
[Electric circuit for addition], [memory address of A],
[Memory address of B] ,[memory address ofK]
A and B are numbers to be added
And K is the answer after adding A and B
It is also a rigid rule that only the names
Of the memory houses are to be given
The parts called registers existing inside CPU
Get copies of the actual numbers a and b
From their respective memory locations
And send them to alu where the required mathematical circuit
For addition is already kept switched on .
All the “instructions” are thus processed
By the CPU one after another
With the help of “registers” (existing inside CPU)
Electric juice simply whirred
All the few dozen working steps (the instructions)
And the final answer for the entire program came
In just a millionth of a second.
. Under supervision of Dr von Neumann and his team
Programmable memoryperhaps on a small scale
and in an experimental waywas introduced
in the old giant size “valve based” electronic calculators
Which used tens of thousands of diode and triode valves
And which required huge air-conditioned halls.
The first experiments in programmable memory
Were done successfully with them.
The teacher writes the dozen working steps
Of an algebra problem on the blackboard
The human engineer’s “computer program”
Loaded on the “main memory board”
Is just similar to the algebra problem..
The human engineer too
Has to type his commands on key board
Only in strictly coded English
Approved by the association
Of electrical and electronic engineers.
Otherwise the CPU itself issues
A red lettered error message
To make the human being realize his/her mistake.