History of Computing

History of Computing History of Computational Technology PLS 021 LECTURE 3 ƒ For centuries, a ‘computer’ was a person who did computations. ƒ Many...
Author: Jodie Marsh
6 downloads 0 Views 372KB Size
History of Computing

History of Computational Technology

PLS 021

LECTURE 3

ƒ For centuries, a ‘computer’ was a person who did computations. ƒ Many tricks and mechanical aids were invented to assist in complicated calculations which could take years to complete (e.g., astronomical calculations). ƒ The computational technology employed was first minimal (fingers, stones on a grid, marks on bones or in clay, pencil and paper). ƒ Later mechanical devices were made, and only after a few millennia were electronics incorporated in calculating devices.

• An overview of the history of computing • Digital biology • A comparison between binary and decimal

Lecture 3

History of Computer Technology

1

Lecture 3

History of Computer Technology

2

In the Beginning

In the Beginning “…necessity is the mother of invention”

“…necessity is the mother of invention”

The earliest abaci were mimics of stones moved on a grid. They were first used in Mesopotamia and later by scribes in Egypt and Greece. Similar devices were ‘invented’ by most ‘advanced’ cultures around the world.

There is a feedback between what Science and Technology can do and what Society wants done or will accept For millennia, astronomical observations were used to predict the future. Calculation used in these astrological predictions were more easily done with the Ptolemaic (150 AD) earth centered model of the universe than with the Copernican Heliocentric sun-centered model (1500 AD). This was one reason the Heliocentric model, proposed as early as 270 BC by the Greeks, was not readily accepted. There was simply no needed for the more complicated model. Later when calculation were needed to more precisely predict specific dates (Easter) or locations on earth (Mecca) the Heliocentric model was adopted.

Lecture 3

History of Computer Technology

3

Lecture 3

What we want to do often exceed what we can do (technology)

History of Computer Technology

The First ‘Computers’ “…necessity is the mother of invention” ƒ Weaving cloth on a loom was a labor intensive activity that was one of the first to be ‘mechanized’ during the Industrial Revolution (1780). Water and later steam power replaced human labor.

Early ideas for the steam engine did not work well because they used a vacuum created by condensing steam rather than pressure made by expanding steam; the cylinders were unable to contain more than one atmosphere of pressure. Newcomen (1712) and Watt (1765) made their steam engines out of metal, and the rest is history. Babbage designed the first ‘computers’ (his mechanical Analytical and Difference engines) years before metal working technology allowed their construction.

ƒ Refinements in the ability to build machines out of metal to exact tolerances, allowed the creation of machines that could produce simple cloth very fast by repeating the same process over and over.

More recently, PIXAR animators had to wait years before computer were powerful enough to allowed them to make feature-length animated movies (e.g., Shorts vs. Toy Story).

ƒ However, these machines could not produce ‘fancy’ fabrics with intricate designs.

Lecture 3

History of Computer Technology

4

5

Lecture 3

History of Computer Technology

6

1

History of Computing

Jacquard’s Loom:

What is not a Computer?

‘programming a loom (1830)’ Punch cards (Stored program) contain information which was ‘translated’ by the loom (Processor) as it weaved threads (Input) into cloth (Output)

Lecture 3

ƒ There is no concept of a program; in order to repeat a calculation the same steps must be repeated by hand. ƒ Computation is “memory-less”; partial results must be written down and re-entered. ƒ Each step requires some manual intervention; thus the calculation doesn’t proceed independently of human control and input.

History of Computer Technology

7

Charles Babbage:

The IPOS cycle

First fully modern computer design

ƒ P. Processing of the data according to a program. ƒ O. Output in a form that is useful. ƒ S. Storage of the results, the input, and the program While the technology is currently electronic, it could be mechanical, or optical, or maybe even biological. History of Computer Technology

9

Analytical Engine (1847) - contained elements of modern computer: it had IPOS cycles > Input (program on punched cards) > Processing unit (gears) > Dials to read output > Storage (memory, cards) These machines could not be built at the time because metal fabrication technology could not produce the fine tolerances needed for the gears. Lecture 3

History of Computer Technology

10

Byron and Shelley

Augusta Ada Byron

A slight digression with Two Romantic Poets At 19, Percy Shelley published a pamphlet “The Necessity of Atheism” which resulted in his expulsion from Oxford (1811). He then traveled to Scotland where he married a 16-year-old schoolgirl. After three years he abandoned his pregnant wife and daughter. He then married Mary Godwin, (aka Mary Shelley) who was the daughter of the author of A Vindication of the Rights of Women. In the summer of 1816, Shelley and Mary made a trip to Switzerland where they met Lord Byron.

When 18, Ada heard a lecture about the difference engine designed by Charles Babbage and started a correspondence with him that lasted many years. She later translated a paper on the function and theory of Babbage's Analytical Engine, and added her own extensive comments which impressed Babbage; he wrote: “… some complicated programs of her own, the most complex of these being one to calculate the sequence of Bernoulli numbers.”

The Shelley's and Byron rented neighboring houses on the shores of Lake Geneva. The summer was unseasonably cold (Global cooling?) and to pass the time they entered into a competition to see who could write the best horror story. Mary Shelley was inspired to write ‘Frankenstein’.

For this reason she has earned the reputation for being the first computer programmer. (However, Babbage and others had written “programs” for the never completed Difference and Analytical Engine before her.) The programming language Ada was named after her. She was the daughter of the famous poet Lord Byron.

History of Computer Technology

8

Difference Engine (1822) It had around 25,000 parts, weighed fifteen tons, and stood 8 ft high, but it was never completed.

ƒ I. Input of data and/or instructions (program).

Lecture 3

History of Computer Technology

What is a Computer? “A computer is an electronic device that performs four basic operations known as the IPOS cycle.”

Lecture 3

Lecture 3

The idea that science and technology were becoming too powerful and could overthrow the Laws of Nature – even to reversing death and making living monsters – was in vogue among European intelligentsia at that time.

11

Lecture 3

History of Computer Technology

12

2

History of Computing

Early ‘Computers’

Charles Babbage’s Difference Engine

A more portable mechanical calculator ‘the Curta’ was invented by Curt Herzstark while he was a prisoner in the Buchenwald concentration camp during WW II. These mechanical ‘calculators’ were similar to the Difference Engine proposed by Babbage. They were considered the best portable calculators available, until they were displaced by electronic calculators in the 1970’s.

In 1991 (after over 170 years ), the London Science Museum built the Difference Engine using Babbage's 1820 plans. It worked perfectly, with an accuracy of 31 digits!

Lecture 3

History of Computer Technology

13

Lecture 3

Herman Hollerith

History of Computer Technology

14

A Slight Digression

and The Automated Census Bureau Hollerith invented (1890): 1) An electronic punching device to store information on punch cards,

Before we consider the development of the modern electronic computer we need to know more about binary numbers and why they are used in computers.

We live in an analog world,

2) An electro-mechanical machine to sort cards, and

but we digitize much of what we experience. ƒ Time is uniformly changing but we use of seconds, minutes, hours, etc.

3) A machine to tabulate data from the cards.

ƒ Length is uniform but we use of inches, feet, yards (or meters) and miles. ƒ Temperature is continuous, but we use degrees.

He founded the Tabulating Machine Co. (1896), which became IBM (1924).

Lecture 3

History of Computer Technology

15

Lecture 3

DIGITAL BIOLOGY

History of Computer Technology

DIGITAL BIOLOGY How many bases (Bits) must be in a codon (a word, Byte) to code for the 20 amino acids?

Are there examples of digital coding in biological systems? DNA (Deoxyribonucleic acid) is made up from 4 bases (A, T, C, G). Each position on the DNA molecule can be any one of the 4 bases. ---A–T–A–C–G–T–A–G–G–T–C---

1 bit (base) per byte (codon): 4 = 4 2 bits (bases) per byte (codon): 4 x 4 = 16 3 bits (bases) per byte (codon): 4 x 4 x 4 = 64

What does DNA code for? The DNA codes for amino acids that make up proteins.

So the ‘word’ in DNA (a codon) must be 3 bases long to code for all 20 amino acids. But 3 bases can produce 64 different combinations. The 44 ‘extra’ codes allow for punctuation (e.g., start, stop) and redundancy in the message (different series of 3 bases code for the same amino acid).

How many amino acids are there? There are 20 essential amino acids; e.g., Glycine, Lysine, Methionine, Serine, Valine, etc.

Lysine = AAA, AAG; Start = ATG; STOP = TGA, TAG, TAA Redundancy in the code ‘protects’ active sites in proteins from being destroyed by random mutations which could alter the amino acid composition of the protein making up the enzyme.

So we need a code using 4 bases that can identify the 20 essential amino acids that are used to make proteins.

Lecture 3

History of Computer Technology

16

17

Lecture 3

History of Computer Technology

18

3

History of Computing

BINARY NUMBERS

BINARY NUMBERS An IP (Internet Protocol) address is composed of four numbers. For example 204.123.169.198 is a valid IP address. The number ‘204’ is one byte. Each of the four bytes is derived from an 8 digit binary number (8 bits), where each of the 8 bits is either a ‘0’ or a ‘1’.

A BIT is a BINARY DIGIT that is either a ‘0’ or a ‘1’. A BYTE is a number of bits grouped into a ‘word; a byte is usually composed of eight bites. Why eight? Before the mid-1960s, bytes were six bits; this coded for 64 alphanumeric characters (26 = 2 x 2 x 2 x 2 x 2 x 2 = 64). That limited the characters that could be displayed to controls, numbers and upper case letters. After the introduction of the IBM System/360 in 1964, which used eightbit characters and supported upper and lower-case letters, numbers and some symbols, the standard size of a byte became eight bits.

History of Computer Technology

+ 26 + 25 + 24 + 23 + 22 + 21 + 20

27 0 or 128

Word sizes thereafter were naturally multiples of eight bits, with 16, 32, and 64 bits being the common derivatives.

Lecture 3

How can we convert 204 into an 8 bit binary number? We first construct a table showing the progressive increase with each binary digit.

19

0 or 64

0 or 32

Lecture 3

26 0 or 64

204 - 128 76

76 - 64 12

1

1

25

+

24

+

0 or 32

23

+

0 or 16

0

0

22

+

0 or 8

0 or 4

12 -8 4

4 -4 0

1

1

21

+

20 = 28 = 256 possible combinations 0 or 1

+

0 or 2

27 0 or 128

0

History of Computer Technology

21

1

0

1

1

0

1

26

25

24

23

22

21

0 or 128

0 or 64

0 or 32

0 or 16

0 or 8

0 or 4

0 or 2

0 or 1

0

+ 16

0

+ 64

x

+

2

x

2

x

+

2

8

x

+

2

0

0 or 64

x

+

2

2

x

+

0

1

Lecture 3

ENIAC:

0

27

2

20

+

25 0 or 32

+

24 0 or 16

+

23 0 or 8

20 - 16 4 0

1

+

22 0 or 4

+

21 0 or 2

20 = 28 = 256 possible combinations 0 or 1

0

0

+

4 -4 0 0

1

History of Computer Technology

22

1940’s – 1950’s

2 = 28 = 256 possible combinations (0 to 255) 20

x

possible combinations

Foundations of Modern Computing

We can also convert from a binary to a decimal number. What is the ‘number’ represented by the 8 digits: 01011010?

2

0 or 1

The decimal number 84 is the binary number 01010100

BINARY NUMBERS

0

26

0

The decimal number 204 is the binary number 11001100

Lecture 3

+

84 - 64 20 0

0 or 2

How about another example? How can we convert 84 into an 8 bit binary number?

A table showing the progressive increase with each binary digit. +

0 or 4

BINARY NUMBERS

How can we convert 204 into an 8 bit binary number?

0 or 128

0 or 8

History of Computer Technology

BINARY NUMBERS

27

0 or 16

= 28 = 256

(Electronic Numeric Integrator And Computer)

It was built to calculate artillery firing tables and break codes in WW II. It had thousands of vacuum tubes, miles of wires and required a lot of power.

= 090

Is 123.456.056.054 a valid IP address? Remember each of the three digit numbers must be represented by an 8 digit binary number. Lecture 3

History of Computer Technology

23

Lecture 3

History of Computer Technology

24

4

History of Computing

The First Generation

The First Generation

1940’s – 1950’s

1940’s – 1950’s A vacuum tube is just an incandescent light bulb with two extra electrodes (gate, anode) inside. The bulb’s filament (Emitter, cathode) is white hot and electrons “boiled off” into the vacuum. The collector (anode) is more positive and cold so negatively charged electrons (e-) flow from the cathode (-) to the anode (+).

The first generation of computers used vacuum tubes which consumed large amounts of energy and failed frequently. First generation computers were often being repaired. Lecture 3

History of Computer Technology

25

Vacuum tube

Gate (variable)

The voltage on a perforated metal screen (gate) regulates the flow of electrons to the anode. Lecture 3

History of Computer Technology

Emitter (cathode -)

Collector (anode +)

26

The First Generation 1940’s – 1950’s

A ubiquitous “punch card” For most of its early history, IBM made most of its profits from selling punch cards, not from selling computers. Lecture 3

History of Computer Technology

27

5

Suggest Documents