2.1 History of Computer Science
Since as long as we can remember, man has felt the need to record
and to process data.
As society got more organized, this need grew steadily.
Writing was inverted so that precise records could be kept and
transmitted to posterity.
Arithmetic flourished out of the need to manipulate figures and
calculations make out an important fraction of the computer
we know today, this is only a fraction of the wide application fields,
realized by the combination of human genius and technology.
In mankind, technology gets developed to assist man in dealing with
tasks, with the technology available.
The invention of the art of printing and the application of purely
(presses, cast letters) illustrate how the technology of an era is
"process data" in the broadest sense.
[art of printing: Gutenberg's Bible in 1450].
In the history of computing, arithmetic plays an important but ever
Since about 2000 B.C. the Chinese and the Egyptians manipulated the
the "beans" on the different branches get different weights and their
indicate which should be taken into account.
Figure 2.1: abacus
Experienced abacus users succeed in fast calculations, however their
ultimately limited by the mechanical nature and the muscular ability of
operator; while the storage capacity is limited to 1 number
(intermediate- or final result).
The Mayans possessed it when the Spanish arrived.
In 1580, Francis Vieta invented the use of letters representing
in mathematical formulas: an essential abstraction.
Follows the concept of "algorithm": a mathematical "recipe", describing
step by step
how to solve a mathematical problem.
In the 17th century, the first mechanical calculating devices
were built after Napier's invention of the logarithms (1614), and his
"bones" (marked ivory rods)
for multiplication: the slide rules.
In 1623, Schickard a German astronomer built a wooden calculator,
and in 1645 Pascal (the famous French mathematician) built an adding
machine, relying on cog-wheels.
This adding machine allowed multiplications by repetitive additions.
During the same period, a new mathematical discipline: "Analytical
by scholars like Descartes and Leibniz, who invented a mechanical
The Renaissance brought several automata such as music boxes and barrel
where the "music" was kept in an "organ book" in the form of punched
cards or a punched
Typical for this generation of machines is the development of
a weaving machine capable of reading punched cards, containing the
for the patterns to be woven.
Notice that the intellectual curiosity was ahead of the industrial
realization at that time!
For the first time we see machines who's actions (the weaving of a
pattern) are determined
by one or more "programs" that are not an integrated part of the
Remarkably, paper-tape (and punched cards) has been in use as the
computer program and
data storage medium by excellence until quite recently (the '70's).
About 1820, the Englishman Charles Babbage developed (with
government aid) a "programmable" machine,
capable to calculate mathematical and statistical tables:
"The Difference Engine".
Figure 2.2: Difference Engine
The apparatus was programmed by punched cards and its main components
bear remarkable resemblance to modern computers:
- an arithmetic unit
- a memory
- in- and output devices
A larger prototype: "Analytical Engine", had to be driven by a steam
however it was never completed.
About 1854, the Englishman George Boole developed a new mathematical
"Boole Algebra", the logic which almost all digital computers
Around 1890, a census had to take place in the United States,
(according to the constitution, in order to determine the number of
every state in the Congress).
The growth of the population made this a technical-juridical problem:
by hand the counting would take longer than the period determined in
How could this dilemma be solved?
Herman Hollerith, himself a US census employee,
developed a census machine, relying on punched cards to treat
to tabulate and sort the results.
He founded a company: the "Tabulating Machine Company", later re-named
He rented the machines but cleverly sold the patented cards.
In 1924, the company was renamed again, to: IBM (International Business
After the first, purely mechanical data processing machines, we must
be patient until around 1930 to find electrically driven (analog)
calculators via projects at the M.I.T. (Massachusetts Institute of
and in private companies (Burroughs).
About 1935, the British Alan Turing, elaborated a theory concerning
More precisely, he demonstrated a number of theorems about digital
driven by "tapes", the so called "Turing Machines".
On a high theoretical level, Turing also demonstrated that some classes
cannot be solved, whatever the computing time devoted to find a
"Digital machines" attribute discrete values to their
variables, in contrast to "analog machines", where the variables
can evolve in a continuous fashion (in a limited range of course).
Analog machines generally rely on currents or voltages that can be
monitored with analog meters or plotters at given points in their
Digital machines work with finite numbers and codes (so called discrete
representations), which have a limited (however small the discrete
compared to the full range) resolution.
In 1934, the German Konrad Zuse in Berlin, built the first mechanical
digital programmable computer: the Z1.
This machine was completed in 1937.
It worked with mechanical switches, a later version, the Z3 (in 1941),
relied on electrical relays.
In 1939, George Stibitz in "Bell Laboratories", built the "Bell
a semi-automatic computer, mostly built with telephone relays.
In that period, Atanasoff and Berry forwarded the idea to build a fully
Howard Aiken (Harvard University) completed the "Harvard Mark 1" in
An electro-mechanical computer, built of +/- 750.000 parts, some 900 km
cable and with a memory realized with cog-wheels!
Instructions were given via paper tape, while data were entered via
To give an idea of the performance: the "Mark 1" performed an addition
in .3 sec.
and needed 6 seconds to multiply two numbers.
The machine was in use for 15 years!
In 1945 Dr. John von Neumann conceived the architecture for the digital
the so called "von Neumann architecture" currently still is by far the
most used structure in the industry.
The first completely electronic "general-purpose" computer is completed
by Eckert and Mauchly at the Pennsylvania University: the "ENIAC"
(for Electronic Numerical Integrator and Calculator).
Some 18.000 electronic valves enabled an addition in 0.2 milliseconds
and a multiplication in
The tremendous heath development of ENIAC required a powerful cooling:
ENIAC weight some 30 tons!
Figure 2.3: ENIAC
In 1947 the transistor was invented.
From this moment on, the electronic computer technology evolved fast:
the realization of magnetic memory (small magnetic cores), the use of
and the "drum" disks were realized in the early '50s.
In 1951, the first commercial computer hit the market:
the UNIVAC I of which 48 were delivered.
Since the commercialization in the beginning of the '50s, the notion of
"generations" was introduced as the technology evolved.
The first generation (1950-1955) mainly relied on vacuum tubes.
Programs were introduces with keys, directly into the memory locations;
or via paper tape and/or punched cards.
Programs and data were strictly separated.
To ease the use of machine instructions (binary codes), each
instruction was given
a meaningful name (mnemonic, like "SUB" for the subtraction
Translation of these symbolic instruction into machine instruction is
"assembling", it is performed by programs called "assembles" or
residing on other machines than the target-machine.
Assembler-programming is a dying art only performed rarely by
Applying transistors as basic building blocks, led to the second
between ca. 1955 and 1965.
Transistors made computers much more compact and reliable.
In this period, the first "higher programming languages" were
FORTRAN (IBM 1956) suited for calculations (scientific problems)
- COBOL, suited for administrative tasks.
These languages greatly fostered the productivity of the programmers,
because they are much more meaningful to the average human mind and
enable the use of more powerful abstractions and pre-programmed
In the same time frame, a whole range of tasks, concerned with the
of the computer itself were automated successfully: the first
Access to the computer was made easier via new input-output devices,
such as interactive CRT screens and printers.
The punched card is the most used medium to store programs and data.
Between 1965 and 1970, the development of Silicon integrated circuits
the third generation.
The first "chips" (Small Scale Integration) were soldered to printed
Via a photo-lithographic method, the cabling scheme could be multiplied
efficiently and reliably.
n the '70s, the chip technology evolved from SSI to MSI (Medium Scale
and later (~'76) LSI (large Scale Integration), even VLSI (Very Large
In the fourth computer generation, data storage is performed in
memory (about 1000 bytes or memory word elements per chip).
Magnetic discs enable the storage of 1 to 10 million
The fourth generation also is characterized by the development of the
"single chip" computer: the Intel 4004 or the Motorola 6800 were
typical exponents, the first "systems" like the "Altair", were
hobbyists, as precursors of the IBM-PC, which hit the market in 1981.
Remarkable also is that the evolution is less and less marked
by individuals, but ever more the result of group efforts emanating
universities, research institutes and companies.
Figure 2.4: PC
At the opposite end of the spectrum, "supercomputers" are designed,
which finally start to enable scientists to manipulate realistic
models of complex phenomena: the weather, astronomy,
fluid dynamics, image processing and physiological processes in living
Figure 2.5: Supercomputer
During the 80's end-user applications come to maturity, as well as
Both local area and world wide networks become operational, mostly
the universities and the pioneering efforts into academic networking
soon followed by the commercial world.
In the last decennium (1985-1995), computers are applied in an ever
widening spectrum of tasks: both "special purpose", targeted at a
application as well as "general purpose", where users can
adapt their applications to their needs, in the framework of a
Programming steadily becomes an activity reserved to
specialists and hobbyists, an ever decreasing fraction of computer
Using and tailoring existing applications to one's needs is the concern
people who want to benefit from computer technology.
Concerning the future, we can look at the main research directions,
- graphical user interfaces (GUI's)
- - computer speech (speech generation and recognition)
- - optical character recognitions (OCR)
- - new architectures: parallel systems
- - multimedia network access: integration of sound-, image- and
Vinton Cerf: Pioneering internet architect
Tim Berners-Lee: inventor of the world wide web
The social impact of the computer as:
daily work horse
- source of information
- vital element in many medical applications
- creator of new industries, new professions and creative
undreamt of in film and music.
should not be underestimated.
As all human activities, the world of computers has its "subcultures",
with tendencies, sometimes with almost fanatic proponents and
Almost religious user groups have originated around applications and
They exchange experiences and information regarding the
topic of interest and give rise to freely available programs, the so
"Public Domain" software.
The worldwide computer network, the "Internet" is used both by the
by the amateur as the medium to exchange information and programs.
The network is the medium for the existence of "virtual communities",
a social development, never seen before!
One thing is certain: once we all get to do with computers in one
way or another, therefore it is essential as an "educated"
person at the end of the 20th century to get a good functional
knowledge and some experience with adequate computers,
in order to benefit as much as possible from this rich technology that
came to existence by the contributions of countless human geniuses!
In following table, we condense the historical overview:
1580 Francis Vieta letters as variables in formulas
1614 John Napier logarithms as calculation tools
1637 René Descartes Analytical Geometry
1642 Blaise Pascal mechanical adding machine
1660 Isaac Newton "Calculus"
Gottfried Leibniz loose from geometry
1805 Joseph Jacquard automatic loom
1820 Charles Babbage "Difference Engine"
1823 Charles Babbage "Analytical Engine"
1853 George Boole Boole algebra (binairy logic)
1890 Herman Hollerith automatic census tabulator
1921 Lee De Forest vacuum tube as switch
1936 Alan Turing theory of automata
1946 John Mauchly first "digital" computer
John Eckert ENIAC (at the M.I.T.)
1948 William Schockley invention of the transistor
John Bardeen (Germanium)
1952 John von Neumann computer architecture
1957 1st computer languages
1965 interactive computer access
1981 development of the "personal computer" IBM-PC
1985 workstations, networks, supercomputers
1990 graphical interfaces
1992 multimedia, ...
1993 multi-processors, optical computers
1994 new architectures??
information highway, Internet commercial, Cyberspace ...
2000 the "millenium bug": from year 99 to 00!
2001 bursting of the "Internet bubble"
2003 this course: revised text.
2.3 From 1981 to 2003 under the spotlight:
August 12th: the first IBM-pc appears on the market for 3.000 dollar.
The IBM-pc is based on the Intel 8088-processor with a clock-speed of
4,77 MHz, a 5,25-inch floppy disk with a capacity of 160 KB and 16 KB
Microsoft introduces together with the IBM-pc the first version of the
operating system MS DOS.
The programming languages Basic, COBOL and Pascal hit the market for
The Hayes Smartmodem 300 is the first modem for the pc.
The spreadsheet program Lotus 1-2-3 (originally written by Mitch Kapor,
later president of the "Electronic Frontier Foundation")
appears on the market and becomes an instant success. Unfortunately,
the IBM-pc is not capable to display the graphics on the screen.
The venue of the Hercules Graphic-adapter, the ancestor of the
"graphics cards", will
enable this later on.
The pc's operating system is far from perfect.
Peter Norton writes the "Norton Utilities", a selection of utility
that make life easier with ms-dos.
Compaq introduces the Compaq Portable pc, a "portable" computer, 12
kilo's heavy, powered
by an Intel 8088-processor. This portable is 3.000 dollar worth.
The Transmission Control Protocol and the Internet Protocol become
known as the standard network protocol stack TCP/IP for the internet.
Microsoft expands its activities. Besides operating system and compiler
they invest in application software: on September 29th, the first
version of the text
processor "word" is presented.
The first network operating system for the pc is developed by Novell:
"Netware". Netware allows pc's in a network
to share files with a server, facilitating greatly file sharing.
The second version of DOS, 2.0, is born on March 9th. Dos 2.0 supports
the new 10-MB hard disks
and 360-KB (5 inch) floppy disks.
On 14 August 14th, the development of PostScript starts, a language
developed to describe the
pages to be sent to a printer. Postscript files are hardware
independent, they would be understood by any type of printer.
After the commercial failure of the Apple III and the Lisa, Apple
launches a new model: the Macintosh. The Mac is based on the
68000-processor, has a graphical interface, with a mouse and is
delivered with 128 KB of central memory. The monitor is black and
Price tag: 2.500 dollar.
Hewlett-Packard launches the LaserJet, the first cheap laser printer
for small office use.
Cost price: about 3.500 dollar.
Intel launches the 80286-processor.
On November 20th, Microsoft launches Windows 1.0.
Without great success, as very little application software is available
The battle between personal computer operating systems is mostly
between DOS and CP/M.
Currently, CP/M leads with 46 percent, followed by DOS with 31 percent.
UNIX occupies a market fraction of 6 percent.
Toshiba commercializes the first laptop computer, the T1100.
This computer is small, lightweight compared to the other "portable"
computers, weighting 10kg on average.
The T1100 becomes a world-wide success.
On March 15, the first commercial domain name is registered:
Next to the 5.25-inch floppy's - which are flexible, the 3.5-inch
diskette appears on the market.
This diskette is packaged in a hard (non flexible) plastic cover and
has a metal clip.
The new floppy's reliability is much higher.
Toshiba launches the first LCD-screen on the market. The screen has a
10 inch diagonal and can display eight colors.
The resolution is 640 x 480 pixels.
The first SIMMs (Single Inline Memory Module) appear on the market.
These make it very easy to extend the computer's central memory, which
was soldered to the main board before.
In August 1986 Intel produces the 80386-processor.
Microsoft is rather active: in August DOS 3.3 is born and two months
later,Windows 2.0 sees the daylight.
More important however for end-users: on October 6th the appearance op
Microsoft Excel for Windows, the first Windows spreadsheet.
The first computervirus, "Brain", starts infecting machines.
Microsoft and IBM collaborate since a few years to produce a new PC
OS/2, of which version 1.0 is launched on April 2nd.
Although Microsoft continues OS/2 development, they bluntly admit the
have more confidence in their own
IBM introduces a new pc-line: PS/2.
The models in this line have new features such as: VGA (Video Graphics
Array) that will become a new
standard. Model 50 en 60 are based on the 80286, but Model 70 is
powered by the 80386-processor.
On November 2nd, Morris, one of the first Internet worms, contaminates
6.000 of the 60.000 Internet hosts. In a few hours time,
the program that is capable of copying itself has propagated all over
IBM and Microsoft introduce OS/2 1.1. This operating system runs only
on a pc with at least an 80286-processor, 4 MB central memory and
requires at least 8 MB disk space.
In Augustus MS-DOS 4.0 appears on the market. This version has a
graphical shell and supports "large hard disks with partitions up
to 512 MB.
IBM launches the first commercial antivirusproduct on the market.
Viruses are taken seriously and
research for the optimal anti-virus strategy is started.
The Internet exceeds 100.000 hosts.
Compaq introduces the first non-interlaced monitor, producing the image
at once on the screen.
More stable to look at!
In August the Intel 80486-processor appears on the market. This
processor has a mathematic co processor built in, important for
spreadsheets and graphic
On May 22nd, Windows 3.0 becomes available. This version shows files
and disks as pictograms and fully exploits the capabilities
of the 80386-processor.
Now that the Internet is at the eve of its commercial explosion,
predecessor Arpanet is dissolved.
Computer viruses evolve fast. The latest sort is the polymorph virus,
that can adapt itself, while propagating.
Another virus type attacks different weaknesses of a system at once.
Not all computers are pc's and not all pc's are IBM-compatible. The
market of the non-IBM-compatible computers is
led by Apple, that occupies 15 percent of the market.
The first commercial Internet provider, giving access via dial-up lines
The World can be found on world.std.com.
Windows 3.11 appears. Four megabytes of RAM are required and 3.11 uses
6MB on the hard disk.
Windows 3.11 will sell 50 million units, for a long timespan, the most
popular version of Windows.
The World Wide Web (WWW) is developed at the "CERN", Europe's
elementary particle research center
near Geneva in Switzerland. Tim Berners-Lee is the main architect and
developer of the
Internet's "killer application".
Linus Torvalds writes the first programming lines of Linux.
Contrasting with commercial operating systems, Linux is available free
of cost as of 1992.
The CD-rom player gives multimedia characteristics (sound and video) to
The term "surf" is proposed by Gene Armour Polly.
Printers improve. The best printouts are generated by laser printers
offering a resolution of 300 by 300 dots (dpi in the jargon).
Hewlett-Packard improves on this by producing its latest LaserJet
model, having a 600 x 600 dpi resolution.
First audio- and video-transmissions via the internet.
In March, Intel introduces a new generation of processors: the Pentium.
Pentium processors are available at clock speeds between 60 and 66 MHz.
Unfortunately, pentium processors make errors
in certain calculations. An arithmetic bug will be fixed later on.
On May 24th the first version of Windows NT is for sale.
With this network oriented operating system, Microsoft wants to compete
with Novell (Netware).
Excel is integrated into Office and progressively bypasses Lotus 1-2-3.
The first version of the browser Mosaic is available. Marc Andreessen'
program is the predecessor of the Netscape-browser
and produces the breakthrough of the World Wide Web.
Novell gets to the market of application software and buys WordPerfect.
Although WordPerfect has been
a market leader in text processing for years, this packet looses the
leadership. In 1996 WordPerfect will be
sold again, this time to the Canadian company Corel, but by then, Word
is the unchallenged market leader.
The White House becomes accessible via www.whitehouse.gov.
Unfortunately, they forget to register the name, and are overtaken by
an "adult entertainment" site!
Marc Andreessen and Jim Clark register Netscape Communications. The
first beta version of their browser Netscape Navigator appears and is
very successful with the first surfers.
In April, Commodore stops its activities. Commodore was one of the
together with Apple, Radio Shack (Tandy) and Sinclair who built "home
computers" by the end of the 70's.
In November, the MPEG format appears, a compressed video format.
The cd-rom has become commonplace: worldwide 29 million cd-rom players
Burning CD's on your own is not possible, until Hewlett-Packard
the Surestore CD Writer 4020i on the market. Its price tag is still
HP soon gets competition!
On August 24, the marketing campaign for Windows 95 starts off.
In some instances, people even sleep in front of their stores to get to
as soon as possible.
In the first two months, Microsoft sells 7 million units.
The first Internet companies go public (on the stock market).
One of the more visible ones is Netscape, in August.
The programming language Java appears (developed by Sun Microsystems).
This platform independent language is considered as "the" solution
for network-wide applications for the Internet.
The ambition is to solve the problem of incompatibility between
written for different platforms.
Toshiba demonstrates the first working Digital Versatile Disk system,
better known as DVD.
In April, 3COM launches its first PalmPilot model, a Personal Digital
Assistant or PDA.
This year, about 9,5 million computers are connected to the Internet.
The first TFT-screens for the desktop appear. These monitors have a
a completely flat screen and are completely free of distortion.
Moreover, they consume only one third of the traditional CRT-monitors'
Microsoft is dragged to court because it couples Internet Explorer to
It will take years for the judge to sentence, but then Microsoft
immediately went to appeal.
To process the media-streams faster, the pentium chips get an enriched
called MMX, in October the Pentium II appears.
Microsoft has a separate version of Windows for the very small
computers - the PDAs - Windows CE. This year,
version 2.0 comes out.
On June 25th, Windows 98 is in the stores. This new version is mainly
targeted toward the consumer.
Compaq acquires Digital Equipment Corporation. A cost of 9,6 billion
The number of domain names breaks records: 2 million domain names are
HP produces its 30 millionth laserprinter.
IBM innovates. The Microdrive is the smallest hard disk in the world:
it can contain between 170 and 340 MB. The disk weights barely 20
Extensible Markup Language - XML - is introduced, to comprise
and data exchange via the web.
Larry Page and Sergey Brin have founded Google in 1998.
Intel produces new processors, among which the Celeron and the Pentium
III. The competition however does not
sleep: Advanced Micro Devices produces the Athlon.
Ricoh announces the first combined DVD-rom, cd-R (Recordable) and cd-RW
(Rewritable) in one drive.
On February 17th, Windows 2000 appears, the long expected successor of
Later in the year, a new "consumer" version of Windows appears:
Windows Millennium Edition, or briefly Windows Me.
In October, Intel shows prototypes of the Pentium 4 in two versions,
with a klockspeed of 1,4 and 1,5 GH (GigaHertz).
A new step in the rave for ever faster processing chips.
America OnLine (AOL) buys mediagiant TimeWarner. The largest fusion
ever (so far).
Originating from the Philippines, the "I Love You"-virus spreads over
Millions of PC's are contaminated.
Bill Gates resigns as CEO of Microsoft on January 13th. His successor
is Steve Ballmer. Gates remains
president of the board and names himself "Chief Executive Architect".
Chip producer AMD starts producing Intels' "Celeron"'s competitor the
Unbothered free exchange of music via the Internet comes to a halt as a
concludes that Napster is at least partly responsible for the breaching
of author rights via its service.
Napster starts filtering protected music.
The follower of the current generation Athlon processors gets the name:
Thereby overtaking Intel, that will only produce a mobile version of
the Pentium 4 next year.
Apple launches its new operating system, Mac OS X, based on UNIX.
By the end of October, Windows XP is in the stores.
Targeted to both the business user and the consumer.
The "Internet bubble" bursts: the whole telecom and ICT worlds are in
Moreover, huge investments made by the telecom industry, lead to
massive over capacity. As a consequence,
the market crashes.
Technological breakthrough of Linux: IBM chooses definitely for Linux
on its complete range of systems.
At the beginning of 2003, there are about 500 million computers in the
Sources: "The Computer from Pascal to von Neumann" door Goldstine,
"Computer Science" door Brookshear,
"Computers and Computer Languages" door Silverman and Turkiew, Tijdnet,