Transcript Agenda

Atanasoff’s Computer
Japan-Bulgaria Mathematics Meeting
— its impact to the present Information Technology
Tokyo Metropolitan University
Chikara Fukunaga
04.09.2009
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Contents
Japan-Bulgaria Mathematics Meeting
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Overview of Atanasoff’s computer
Algorithm used in the computer
Logical circuits with vacuum tubes
Performance
Summary
Historical position of the computer
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Atanasoff’s computer
Japan-Bulgaria Mathematics Meeting
• John Vincent Atanasoff and Cliff Berry developed a computing
machine (Atanasoff & Berry Computer; ABC) to solve linear
simultaneous algebraic equations with max. 29 unknowns at
Iowa State University in 1940
Джон Винсент Атанасов
(1903-1995)
His father was an
immigrant from Bulgaria
• Although the machine was for the specific purpose, was
neither stored-program architecture nor universal, it is
regarded now as the origin of the digital (electric) computer.
He was regarded as an inventor of it
• We try to clarify the above reasons through this talk
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Japan-Bulgaria Mathematics Meeting
Principal structure of Atanasoff’s computer
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Synchronization and Control Scheme
Japan-Bulgaria Mathematics Meeting
• Synchronization has been achieved by a purely mechanical way :
electric motor (900rpm) + worm gear (15:1) system
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Atanasoff’s Algorithm
Japan-Bulgaria Mathematics Meeting
• Forward part – elimination of coefficients of x1 to xn one by one
• With max. 28 pairs (for j=2…29), number of unknowns reduced to 28, and
27,26, … finally we get value of Xn
• Backward substitution using the same algorithm used in forward part
…..
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x1
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Japan-Bulgaria Mathematics Meeting
Algorithm 2 update of aij
• aij=aik – (akk/akj)aij
is the principle
calculation for
both forward and
backward
akj,j=k..n+1 to Keyboard drum
aij,j=k..n+1 to Counter drum
• Atanasoff tried to
make (akk/akj) with
only addition and
subtraction
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Logical circuit for arithmetic calculation
Japan-Bulgaria Mathematics Meeting
Atanasoff newly
– Introduced logical operation for Arithmetic calculation
– devised the following logical table for full adder and
subtractor before the switching theory was born
Truth Table for 1bit full adder/subtractor
– And realized this logic
Adder
Subtractor
in a circuit with vacuum
Input
Output
Output
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B
Carry
X
Carry
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Carry
tubes (tri-poles) and
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resistors network
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– Eventually established
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the base of present
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digital computer system 1
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Logical circuits with vacuum tubes
Japan-Bulgaria Mathematics Meeting
• A combination circuit can be constructed with three
logical components NOT, NAND and NOR.
• NOT, NAND and NOR can be realized with a resisters
network and one tri-pole tube.
High voltage
voltage
Low
~+V
~0 Vplate
(ground)
HighLow
Voltage
Voltage
ON
OFF
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Adder output from NOT,NAND and NOR
Japan-Bulgaria Mathematics Meeting
• We can construct the Adder output with combination of
NOT,NAND and NOR
Input
• Atanasoff established in this way
logic circuits of full adder/subtractor
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Adder
Output
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Carry
Subtractor
Output
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Carry
A
B
Carry
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Performance
• Computing time estimation from
Japan-Bulgaria Mathematics Meeting
A.R.Burks and A.W.Burks “The First Electronic Computer:
The Atanasoff Story”, 1988, Univ. Michigan
• Anatasoff estimated time=n3/64 hours if we used a table
calculator of that time (1940), and it was 380 hours with n=29
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Summary: What did Atanasoff established
• Digital electric computation
– abandoned to use (old fashioned) analogue computers
– brought “digital computation” into the calculation machine system
Japan-Bulgaria Mathematics Meeting
• Electric switching
– used a vacuum tube as a simple on/off switch
– implemented Boolean logic (truth table) calculation with vacuum tube
circuits
• Memory
– Separated memory from arithmetic operation unit (new architecture)
– Chose capacitor as the memory element, and refresh system (
DRAM)
– developed Rotary drum memory
(
magnetic drum, hard disk)
• Sequential control system
– Introduced sequential and synchronization concept for machine control
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Japan-Bulgaria Mathematics Meeting
Historical position of Atanasoff’s computer
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Follow up 1
Japan-Bulgaria Mathematics Meeting
Computer programming
Programming sequence of
a computer program will be expressed as follows ;
– It usually consists of
• Sequential operation
• Condition Jump (Branch)
• Loop (repetition)
For carrying out such a complicated script,
we need various hardware
components for a computer
– Memory (to store program,
variables and constants）
– Arithmetic and Logical Operation Unit
– Registers for Arith./Logic Unit and status
– Control system
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Follow up 2
Basic hardware structure of a processor
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• A typical (simplest) structure will be depicted as
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Follow up 3
von Neumann architecture (1945)
The following conditions are required to be fulfilled in if a
machine is regarded as a modern (universal) computer :
Japan-Bulgaria Mathematics Meeting
– Memory access through the address (linear address)
– Stored program architecture
• program and data are stored in mix in memory
– Program logic dependency
• No distinction between program instructions and data in
memory
• Distinction can be made only by the concerned program
• If the logic in program is intentionally setup so, the
program can also modify instructions like data
– Sequential instruction execution
• A register holds the address of the next instruction to be
executed. Instructions are done one by one sequentially
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