CSCI-235
Micro-Computers in Science
Course Information & Introduction
• Class webpage
http://www.stfx.ca/people/igondra/csci235
• What is a computer?
A good start at defining what a computer is might be:
“It is a device that processes data and produces
information”
• Is this a good definition?
It is far too broad in its applicability. With this definition,
many things can be classified as a computer (e.g., a
thermostat, a VCR)
• What is this definition missing?
Have you ever written a term paper on your VCR or
calculated your tax return with your thermostat?
Those devices were manufactured with the ability to
perform a single, limited task
• A computer can be programmed!
There is a particular kind of data that a computer
requires in addition to any other data it might receive: a
program
Better definition: “It is a programmable device that
processes data and produces information”
Is the human brain a computer?
• Gross Anatomy
Hardware: equipment associated with the computer
• Input devices, processor, output devices, storage
Software: instructions that tell the hardware what to do
Two categories of software:
• System software
• Application software
• von Neumann Architecture
Although specific components may vary, virtually all
modern computers have the same underlying structure
known as the von Neumann architecture
Named after computer pioneer, John von Neumann,
who popularized the design in the early 1950's
• The von Neumann architecture identifies 3
essential components:
Input/Output Devices (I/O) allow the user to interact with
the computer
Memory stores information to be processed as well as
programs (instructions specifying the steps necessary
to complete specific tasks)
Central Processing Unit (CPU) carries out the
instructions to process information
• First “computer”?
The first actual calculating mechanism known to us is
the abacus, which was invented about 2000 years ago
Many references cite the French mathematician,
physicist, and theologian Blaise Pascal as being the
inventor of the first mechanical calculator in 1642, the
Arithmetic Machine
However, it now appears that the first mechanical
calculator may have been conceived by someone else
almost 150 years earlier than Pascal's machine. Can
you guess who?
• Leonardo Da Vinci
In the early 1800s, a French silk weaver called JosephMarie Jacquard invented a way of automatically
controlling the warp and weft threads on a silk loom by
recording patterns of holes in a string of cards
The first device that might be considered to be a
computer in the modern sense of the word was the
Difference Engine to automatically calculate
mathematical tables conceived in 1822 by the British
mathematician and inventor Charles Babbage
The Difference Engine was only partially completed
when Babbage conceived the idea of another, more
sophisticated machine called the Analytical Engine
The Analytical Engine was intended to use loops of
Jacquard's punched cards to control an automatic
calculator, which could make decisions based on the
results of previous computations
Working with Babbage was Augusta Ada Lovelace, the
daughter of the English poet Lord Byron. Ada, who was
a splendid mathematician and one of the few people
who fully understood Babbage's vision, created a
program for the Analytical Engine
Ada is now credited as being the first computer
programmer and, in 1979, a modern programming
language was named ADA in her honor
In 1939, a German engineer, Konrad Zuse built the first
programmable, general-purpose digital computer. His
computer was built from electric relays to automate
engineering calculations
• “I was too lazy to calculate and so I invented
the computer.”
John Atanasoff invented the Atanasoff-Berry Computer
(ABC) —the first electronic digital computer. Built in
1939, this computer used vacuum tubes and was based
on binary arithmetic. It was never a fully operational
product
In 1944, Howard Aiken completed the Mark I, the
largest electromechanical calculator ever built. It was
built with electromechanical relays and followed
instructions punched in paper tape
• The first computer “bug”
In 1945, Mauchly and Eckert built the ENIAC (Electronic
Numerical Integrator and Computer). The ENIAC was
built with 18,000 vacuum tubes that failed on an
average of once every seven minutes
After the war, they created the UNIVAC I - the first
general-purpose commercial computer
• First-Generation Computers
1930s – 1940s
Vacuum tubes used as switches
Large computers
Extremely slow by today’s standards
Prone to frequent failure
Includes the ABC, Mark I, ENIAC, UNIVAC,
and others of similar design
• Second-Generation Computers
1950s – mid-1960s
Transistors used as switches
Smaller than vacuum-tube-built computers
As much as a thousand times faster than
first-generation computers
More reliable and less expensive
• Third-Generation Computers
Late 1960s
Hundreds of transistors packed into a single integrated
circuit on a silicon chip
Dramatic reduction in size and cost
Significant increases in reliability, speed, and efficiency
Mass production techniques to manufacture chips
inexpensively
• Fourth-Generation Computers
1970s to present
Complete computer on a chip
Radical change in the appearance, capability and
availability of computers