Overview of Computer Science
CSC 101 — Summer 2011
History of Computing Overview
C
Computer
t S
Science:
i
Th
The Big
Bi Picture
Pi t
Lecture 2 — July 7, 2011
Announcements
• The latter slides in this lecture are meant to be a
complement
p
to the video “Giant Brains” which
we will watch in class Today
• Writing Assignment #1 Due Monday
– Assignment can be found on course webpage
– Print out assignment and hand in to me before class
– Bring electronic copy with you to lab1 on Tuesday
2
Objectives
• Video on the History of Computing
• What is “information”?
– What is “digital information”
• Layers of abstraction in computing systems
• Understanding Moore’s Law
• Reading:
– PotS: Preface (VII-XI)
– CSI: 2-17 / 24-27
• http://www.thocp.net/timeline/timeline.htm
3
1
Information
• How does “information” differ from “data”?
– Data:
• Basic values or facts
• No special meaning
– Information:
•
•
•
•
•
Knowledge derived from study, experience, or instruction
Facts with significance or meaning
What is known beyond chance predictions
Data that has been organized or processed in a way that makes it useful
Communication that has value because it informs—
helping to answer questions and solve problems
• Information is useless unless it can be communicated
–
–
–
–
Vocalizations
Symbols
Spoken and written languages
Analog and digital technologies
4
Information
• Some ways to carry and exchange information
–
–
–
–
–
Books and newspapers; paper documents
Numbers and numerical data
I
Images,
music
i andd video
id
Artistic expressions
Live broadcasts
• Radio, television, etc.
– Direct communications
• Face-to-face, telephone, postal mail, email, IM, etc.
• Collectively often referred to as “media”
5
Digital Information
• Many different kinds of information;
many different types of media
• All can be represented “digitally”
– A pattern
tt
off simple
i l numbers
b (digits)
(di it )
• Could be any set of digits
– “0” and “1” are particularly simple and easy for a machine
• “binary”
– Binary data is the universal language of today’s computers
• The process of converting information into a numeric
(digital) representation is called digitization
6
2
Digital Information
• Once information has been converted into digits,
it’s just a bunch of numbers.
• What can we do with a file full of numbers?
7
Digital Information
• Once information has been converted into digits,
it’s just a bunch of numbers.
• Since it’s just numbers, it can be:
– Easily stored
(no matter what kind of information)
– Easily copied (at full quality)
– Easily combined or modified (edited)
– Easily transmitted or shared
– Easily taken (copied) without permission
8
Layers of Abstraction
• An abstraction is a kind of
simplification
– A way to think of something
without worrying about
specific details
– Consider an automobile
• Abstractions are an important
part of computing
– When you send an email, you
don’t need to think about all
the details of how it actually
gets sent
• This course will look at many
different levels of abstraction
9
3
Layers of Abstraction
• Can consider computing systems from many different
levels, like layers of an onion
Communications
Applications
Operating Systems
Programming
Hardware
Information
10
Computer Science
• A computer is any device that processes
information based on some instructions
– Information goes in (input)
– That information is processed
– Different information comes out (output)
• What do we mean by “computer science”?
Computer Science is no more about computers
than Astronomy is about telescopes.
—Edsger Dijkstra(1930–2002)
– It’s not just about writing or using programs
– It’s not just about the Web or the Internet or email or word processing
– It’s not just about the latest Xbox
11
Computer Science vs. Information Technology
• Computer Science (CS) is the discipline that
studies the theoretical foundations of how
information is described and transformed
• Information Technology (IT) involves the
development and implementation of processes
and tools (both hardware and software) for
describing and transforming information
12
4
Computer Science vs. Information Technology
• Many aspects of “computer science” and
“information technology”
–
–
–
–
–
–
Programming concepts and languages; software engineering
Computer hardware engineering (architecture)
C
Computation
t ti theory;
th
algorithms
l ith andd data
d t structures
t t
Information management (informatics)
E-commerce and information protection; security and privacy
Etc., etc., etc.
• Through the implementations of information technologies,
computer science has a direct impact on almost every aspect of
our daily lives
– We all, then, benefit from an understanding of the field
13
Electric vs. Electronic
• The very first computing devices
used mechanical levers and dials
• After the advent of electricity,
electrical relays
y were used ((1835))
– A great improvement over
mechanical levers and gears
– Slow, heavy, prone to fouling
• In the 1940’s, electronic vacuum
tubes began to be used
– Faster
– Very hot and prone to failure
14
Electric vs. Electronic
• In the 1950’s the electronic
transistor was invented
– “Solid state”
• No vacuum tubes
• No mechanical devices (relays)
– Smaller, faster, more reliable,
cheaper than vacuum tubes
• Integrated circuits were
developed in the 1960’s
– Large numbers of transistors on
a single chip of silicon
• The Intel 4004 CPU had 2,250 transistors (early 1970’s)
15
5
Electric vs. Electronic
• VLSI (very large scale integration) circuits are
now common
– Over 1,000,000,000 transistors on a single, tiny chip
~1 inch
~0.25 inch
16
Price–
Price
–Performance Over Time
Year
Name
Performance
(adds/sec)
Memory
(KB)
Price
(2010 $)*
Performance/Price
(vs. UNIVAC)
1951
UNIVAC I
1,900
48
8,400,000
1
1964
IBM S/360
500,000
64
7,030,000
314
1966
1976
1981
(mainframe)
PDP 8
PDP-8
(minicomputer)
Cray-1
(supercomputer)
IBM PC
33,000
4
111,000
1,300
166,000,000
32,768
15,300,000
48,000
240,000
256
7,200
147,000
50,000,000
16,384
11,800
18,700,000
Apple iPhone 4
1,000,000,000
524,000
700
6,320,000,000
Lenovo T410
ThinkPad
2,400,000,000
3,146,000
1,300
8,200,000,000
(original PC)
1991
HP9000/750
2010
2010
(workstation)
(WFU std issue)
* adjusted for inflation to 2010 based on consumer price index
17
Moore’s Law
• John Moore, co-founder of Intel
• Predicted in 1971 that the number of transistors on a chip
(and therefore its speed) would double about every year or so.
• Actual:
# of transistors
doubles about
every 2 years
• Price/Performance
(previous slide)
doubles about
every 1.7 years
http://www.intel.com/technology/mooreslaw/; http://en.wikipedia.org/wiki/Moore's_law
18
6
Extrapolating Moore’s Law
• How long can this
continue?
– Transistors
i
needd to
be smaller to fit
more on a chip
– What happens if they
need to be smaller
than an atom?
19
A Brief Taxonomy of Computers
• Servers
– Computers designed to provide software and other
resources to other computers over a network
• Workstations
– High-end computers with extensive power for
specialized applications by individual users
• Personal computers
– General-purpose computers for single users
20
A Brief Taxonomy of Computers
• Portable computers
– Devices that can easily be moved
• Laptop (notebook) computers
• Handheld computers
p
• Embedded computers
– Special-purpose devices with
non-standard interfaces
•
•
•
•
•
•
In-car navigation systems
Home security systems
Building management systems
Set-top cable TV boxes
Game consoles
Etc., etc.
21
7
Clusters and Grids
• Many inexpensive computers working together to solve
large problems
– Cluster – all in one location
– Grid – “distributed computing” – many locations but working together
22
Clusters and Grids
• The “Gravity Grid” at
UMass Dartmouth is a cluster of
PS3 boxes for simulating black
hole dynamics
http://gravity.phy.umassd.edu/ps3.html
23
Computer Technology Overview
• History of computer technology can be divided into five
generations:
–
–
–
–
–
Early: abacus, mechanically driven / programmed, Turing machine
1st: Vacuum tubes used to store information
2nd: Advent of transistor / Immediate access memory
3rd: Integrated Circuits / Moore’s Law / Terminal
4th: Large Scale Integration / Personal Computer
• Recurring theme of need (often military) pushing
innovation
– WWII pushed the creation of MARK1 and ENIAC
• The Rest of the slides in this video are meant to complement the video we
watched in class today.
• You might find some of the information useful as a review
24
8
Origins of Digital Computers
• The first digital computer
• But, fingers aren’t sufficient for big problems
25
Origins of Digital Computers
• Earliest computing devices were designed to aid
numeric computations
• The abacus was first developed
p in Babylonia
y
over 3,000 years ago
• Decimal number
system – 11th century
• Algebraic symbols –
16th century
26
Early Calculating Machines
• Blaise Pascal (France, 1623–1662)
– Pascaline – addition and
subtraction only
27
9
Early Calculating Machines
• Gottfried Wilhelm von Leibniz
(Germany, 1646–1716)
– Stepped Reckoner
– All four arithmetic
functions (+ – × ÷)
28
Charles Babbage
• England, 1791–1871
• First true pioneer of modern
digital
g
computing
p
g machines
• Worked on two prototype
calculating machines
– Difference Engine
– Analytical Engine
29
Babbage’s Difference Engine
• A special-purpose machine (designed to calculate
and print navigational tables)
• Used the “method of differences” to solve
polynomials
l
i l
• Current manufacturing
technology was
insufficient –
the Difference Engine
never really worked
30
10
Babbage’s Analytical Engine
• A general-purpose machine
(programmable)
• Based on the idea of the
Jacquard loom
– Fabric pattern stored
on punch cards
• Had the basic parts of
every modern computer
– Input and Output
– “Mill” (processor)
– “Store” (memory)
31
Babbage’s Legacy
• Babbage’s Analytical
Engine was perhaps the
first general-purpose,
digital computing device
• But, his ideas and achievements
were forgotten for many years
32
Konrad Zuse
• Germany, 1910–1995
• Between 1936 and 1943 designed
a number of general-purpose
computing machines
• Used electromechanical relay switches
– (Not electronic yet)
– No longer based on levers and gears
• Offered his technology to the German government to help
crack allied codes, but was turned down
– Nazi military felt their superior air power was all they needed to
win WWII
33
11
Howard Aiken and Grace Hopper
• Aiken (1900-1973) designed, and Hopper (1906-1992)
programmed the Harvard Mark I (1944)
– Used by the Navy for ballistic and gunnery table calculations
– Electromechanical relays
• Hopper’s group found
the first actual computer
bug – a moth that had
caused the Mark I to fail
• Hopper also invented
the compiler
(more on compilers later)
34
The Harvard Mark I
35
John V. Atanasoff
• US, 1903–1955
• With grad student
Clifford Berry built the
ABC machine
hi (1939)
• First electronic digital
computing machine
(vacuum tubes instead of relays–smaller & faster)
• A special-purpose machine
(for solving simultaneous equations)
• First to use binary numbers
36
12
John Mauchly and J. Presper Eckert
• Mauchly (1907–1980) and Eckert (1919–1995)
• Headed ENIAC team at U. Penn
• ENIAC (Electronic Numerical Integrator and
Computer) was the first electronic, generalpurpose, digital computer
• Manually programmed
• Commissioned by the US Army during WWII for
computing ballistic firing tables
37
ENIAC
• Completed 1946 (after the end of the war)
• Massive scale (30 tons) and redundant design
• Data encoded internally
in decimal
• Detailed histories of ENIAC and other early computing devices can be found at
http://ei.cs.vt.edu/~history/ENIAC.Richey.HTML
and http://ftp.arl.mil/~mike/comphist/
38
ENIAC
• Manually programmed by boards, switches, and “digit trays”
• Programmed by a group of female mathematicians working for
the Army as ‘clerks’
– The first six were inducted into the Women in Technology International
Hall of Fame a half-century later (1997)
39
13
John von Neumann
• Hungary, 1903–1954 (moved to US in 1930)
• Pronounced “NOI-mahn”
• Developed the stored program
concept
p
– No more manual programming!
– Published his ideas in 1945
• Helped Mauchley and Eckert design EDVAC
(Electronic Discrete Variable Computer) at
U. Penn (1949)
• He later conceived of the cold-war principle of
Mutual Assured Destruction (MAD)
40
John von Neumann
• Designed the IAS machine (1951) at Princeton’s
Institute for Advanced Study (IAS)
– Implemented a new model
for computer organization:
“The von Neumann
Architecture”
We’ll cover the von Neumann
architecture in detail later
41
Alan Turing
• Great Britain, 1912–1954
• Developed a simple,
abstract, universal
machine model for
determining computability
42
14
Alan Turing
• Led the ULTRA project that, during WWII, broke the
code for Germany’s Enigma machine
• Constructed Colossus
(1943) which was
(1943),
used to crack the
Nazis’ Enigma code
– Details still classified
– 2400 vacuum tubes
• Often considered a
major breakthrough
towards ending WWII
43
Commercial Computers
• In the early 20th century, advances in
computational technology were mostly from
research projects
• Large investments in these research projects
came from wartime needs during WWII
• After the war, computational technologies began
to be developed into commercial products
44
Commercial Computers
• UNIVAC 1 (1951)
– Mauchley & Eckert
– First commercial, generalpurpose computer system
– Vacuum tubes
– Liquid mercury memory tanks
45
15
Commercial Computers
• IBM System/360 (1964)
– Solid-state circuits
(transistors and
i
integrated
d circuits)
i i )
– Family of compatible
models
– Defined the idea of
“mainframe” for
decades
46
Commercial Computers
• DEC PDP series (1970’s)
– “Minicomputers”
– Mainframe performance at a
fraction of the cost
• Cray 1 (1976)
– “Supercomputers”
– High-performance systems
for “number crunching”
– Advanced designs
47
16