We know that the group of mathematical circuits
In the ALU is the real computer,
It is the first original computer
Which existed even before Dr von Neumann’s time.
Dr.von Neumann was a great computer architect.
He and his coworkers completely changed
The concept of calculating machines
He wanted that the alu should do only mathematical work
And should not be encumbered
By other electrical switching work
So he proposed that the part
Which we call now as the CPU
Should be given all the duties regarding switching
And checking of the hundreds of thousands of electric circuits existing in computer
He proposed that CPU be made the commander- in- chief,
And the chief switching officer.
 |
| Dr. Von Neumann next to the ENIAC computer in 1948 |
Through the maze of logic circuits
Which was called computer before his days
The eight bit codes of numbers only flowed
And never stayed unmoving at any one place .
They only flowed and flowed from part to part
Through the eight lane and sixteen lane super highways
Mathematical Problems went in
And answers flowed out in fraction of a second.
The speed was too terrific
And was not of much use except to the military men
Who wanted to destroy incoming missiles
Even these old computer circuits
But Dr Neumann was bent upon detaining
The number codes travelling
Inside the computer’s superhighways
For a few microseconds for examination.
He wanted them to be thoroughly examined
Before entering the mathematical fort called ALU
He wanted that even the answers
Flowing out from ALU should be detained.
The parts called registers were created
They were like specially trained office clerks.
The registers were actually long rows
Of flip flop chambers with complicated circuitry.
In the registers the eight bit or sixteen bit codes
Could be detained for checking
Just for a millionth of second
And then sent to their destinations
Sometimes the long codes are cut into smaller codes
And the smaller codes too are cut
Into still smaller codes and sent to other registers
Through the electrical superhighways
Of eight lane or sixteen lanes in a most perfect way
The registers were like well trained office clerks
Of a big office or a bank
But far more important than even the registers
Was the new “magnetic memory board”
Introduced by Dr von Neumannn’s team
It is called by the very special name “main memory”
It is the place where the 010101 binary codes of numbers
Could stay even for an hour or two
Or for any length of time as long as computer is switched on.
This facility gave mighty power to the computer
Which was till then only something of a mathematical toy
A maze of electrical wires and was
An uncouth number- crunching thing.
.
The wonderful “magnetic memory board”
Put by Dr von Neumann in side the computer
Was as important as the CPU and ALU .
All these three are mutually helping friends.
The memory board was of quite small size
It could fit into the computer
It is made of eight- room or sixteen- room barracks
Constructed from extremely tiny magnetic rings
The engineers used high technology.
These submicroscopic rings created
A magnetic city with thousands of memory houses.
It is like a great city with thousands
Of parallel and perpendicular electric roads.
The tiny magnetic rings are fixed to the plastic board
In perfect rows and columns as on a graph paper.
A large number of parallel and perpendicular wires
Brought in currents to the magnetic rings
The parallel and perpendicular wires were thin and invisible
And looked like a tiny graph sheet.
Through every ring passed two wires
Each was perpendicular to the other
Only that particular tiny ring
Lying at the crossing of the wires
Could be magnetized or demagnetized
When currents were passed through
A particular pair of wires.
Suppose some rings are magnetized
To saturation and some are entirely demagnetized.
Then the magnetized rings represent Boolean ones
And unmagnetized rings represent Boolean zeroes!
If the rings are grouped like the eight or sixteen
Barracks ,each such group can represent
A number or a letter of alphabet
Or even a symbol like question mark,comma or a full stop!
Dr von Neumann ordered that the human engineer
Should type specific “instructions”, perhaps a dozen or two,
Onto the main memory board in zero-one code
For strict compliance by the CPU!
The engineer would use a key board like that of a typewriter
To type the serial numbered “instructions”
Right onto the main memory board.
The “instructions” were like simple sentences
Or like the working steps in an algebra problem.
If the CPU is the boss for all the computer,
The human engineer is the boss for the CPU!
Just as an assistant gets written orders from his Boss the CPU too gets written orders
In the form of coded “instructions”
Typed on the magnetic main memory board.
The main memory board in turn sends
Electrical copies of these instructions
(Contained in the memory houses on it) to the CPU
Through the eight or sixteen lane superhighways
But the travelling of 010101 codes of numbers
And the switching of mathematical circuits in ALU
Becomes possible only if the CPU switches
The required electric circuits in a most accurate way.
The CPU should also first check
All the thousand tiny electrical connections
Lying inside the computer
And keep them perfectly hale and strong
Then only the CPU is authorized
To switch off and switch on
The mathematical circuits inside the ALU.
(The ALU is the all powerful mathematical brain).
Suffice it to say that if there were no main memory board
Which is like a black board fixed right inside computer
To write the human engineer’s instructions
The modern electronic calculating machine,the computer,
Would not have seen the light of the day at all.
Now a days the software engineer loads even
Fifty thousand coded instructions at a stretch in “C”language which the CPU processes on its own.
There is only an occasional “conversation”
Between the computer and the man
There is a rare blinking red message from the CPU
Or an occasional veto from the engineer.
But all this is Dr .von neumann’s grand plan.
By Sastry Polavarapu (Admin at PDEP)
No comments:
Post a Comment