Introduction to Computer Systems
Computers in Our World
Computers are everywhere
We can find them in pretty unlikely places
- Family car
- Home appliances
- Alarm clock
The Computer Defined
An Electronic device that converts data into information which is useful to people
Anatomy of a Computer
Every computer has four basic parts, or units:
- an input unit such as the keyboard, that feeds information into the computer
- a central processing unit (CPU) that performs the various tasks of the computer
- an output unit , such as a monitor , that displays the results;
- a memory that stores information and instructions.
Computer vs Human
- Input – Five senses
- Central Processing Unit (CPU) – brain
- Output – Body Parts
- Memory – Human memory
Programs for operations and problem solving
Modern computers are digital
- Word “by the numbers”
- Break all types of information into tiny units
- Use numbers to represent information
- Two digits combine to make data (0, 1)
History of Computers
Older computers were analog
- represent data as variable points along a continuous spectrum of values.
- More flexible but not necessarily more precise and reliable
Older computers were analog
A more manageable type — the old-fashioned slide rule
- 3000 BC: The first calculating device ABACUS was invented in Egypt .
- The abacus is still in use in some countries especially China, Japan
Addition, subtraction, division and multiplication
Extract square root and cube root
- User has to memorize certain rules
- 1642: A Frenchman Blaise Pascal introduced the first mechanical calculating device.
- Series of wheels with teeth which could be turned using hands
- Used to handle 999,999.99
- Perform both addition and subtraction.
- 1833: Charles Babbage
Professor of Mathematics
With Assistance of Lady Augusta Ada Lovelace
- developed a machine that could store information, calculate numbers and solve algebraic expression.
- 1890: Herman Hollerith
- developed devices that were able to read information which had been punched into cards automatically
- developed a machine called the census machine
US Census Bureau.
Capable of reading numbers, characters, and also special symbols.
Harvard Mark I
- 1944: Howard Aikens and Grace Hooper developed an electromechanical machine at IBM
- Called Automatic Sequence Controlled Calculator (ASCC)
- Called Mark I by Harvard University
- Capable of reading numbers, characters, and also special symbols
- Built from Switches, Relays, rotating shafts and clutches
- 765,000 components
- Hundred of meters of wires
- Length (51ft) X Height (8 ft) x Depth (2 ft)
- Weight 4500 kgs
- Used decimal number systems
- 1946 First general purpose electronic computer
- Electronic Numerical Integrator And Computer (ENIAC)
- Technology used
Vacuum tubes 17,468
Crystal Diodes 7,200
Hand soldered joints 1 million
- Weight 27 tons
- Volume 100 ft (L) X 8 ft ( H) X 3 ft (D)
- Covers 1800 sq. feet
- Power consumption 150 kW
- Uses punch cards
- Averages 5,000 operations
Manchester Mark I
- First stored program computer,
- Based on Von Neumann architecture
- Manchester Mark 1 , built in UK. Using valves ,
- it can perform about 500 operations per second and has the first RAM .
- It fills a room the size of a small office.
Ferranti Nimrod Computer
1951 : Early computer game , Nim
Played by Ferranti Nimrod computer at the Festival of Britain.
History of Microcomputers
1965 DEC PDP 8 produced in US
First commercially successful microcomputer,
Programmed Data Processor (PDP)
It sits on a desktop
H 316 Kitchen Computer
1965 Honeywell corporation
First home computer
Intel 4004 Microprocessor
- 1971 Intel 4004, the world’s first commercially available microprocessor.
- four-bit computer containing 2,300 transistors
- can perform 60,000 instructions per second.
- Designed for use in a calculator
- Sells for $200
- 1972 : 5.25-inch floppy diskettes are introduced
- providing a portable way to store and move data from machine to machine.
Intel 8008 Microprocessors
- Intel announces the 8008 chip.
2-MHz, eight-bit microprocessor
can access 64 KB of memory
used a two-byte addressing structure
over 6000 transistors on one chip
can perform640,000 instructions per second.
- Motorola introduces the 6800 microprocessor.
8 bit processor
used primarily in industrial and automotive devices.
1975, first commercially available microcomputer
- 64 KB of memory
- open 100-line bus structure.
- sells for $397 in kit form or $439 assembled.
1976 Steve Wozniak and Steve Jobs build the Apple I computer.
- less powerful than the Altair, but also less expensive and less complicated.
- Users must connect their own keyboard and video display, and
- have the option of mounting the computer’s motherboard in any container they choose — whether a metal case, a wooden box, or a briefcase.
1977 Mass produced personal computer,
Commodore PET (Personal Electronic Transactor ) appears.
- 1981 First portable computer, Osborne 1, produced.
- At the size and weight of a sewing machine,
much less convenient than current portable computers.
weighs about 22 pounds
Two 5.25-inch floppy drives,
64 KB of RAM, and
a five-inch monitor but no hard drive.
based on the z80 processor, runs the CP/M operating system, and
sells for $1,795.
The Osborne 1 comes with WordStar (a word processing application) and Super-Calc (a spreadsheet application).
It is a huge success.
1981, IBM introduces the IBM-PC
- 4.77 MHz Intel 8088 CPU,
- 16 KB of memory,
- a keyboard,
- a monitor,
- one or two 5.25-inch floppy drives, and
- A price tag of $2,495
1984 Apple Macintosh computer becomes first successful personal computer with a mouse and easy to use Graphic User Interface (GUI).
Windows, Laser Jet
- Intel releases the 80386 processor (also called the 386),
a 32-bit processor that can address more than four billion bytes of memory and performs 10 times faster than the 80286.
- Aldus releases Page-Maker for the Macintosh,
the first desktop publishing software for microcomputers.
- Microsoft announces the Windows 1.0 operating environment,
featuring the first graphical user interface for PCs mirroring the interface found the previous year on the Macintosh.
- Hewlett-Packard introduces the LaserJet laser printer, featuring 300 dpi resolution.
Generation of Computers
|1st||1944-59||Use Valves (Vacuum tubes)|
|3rd||1964-75||Large Scale Integrated Circuits|
|4th||1975-||Very Large Scale Integrated Circuits|
|5th||Under development||“Artificial Intelligence” based computers|
What is a computer?
Comparison of Computer with Human
History of Computers
Developments in Microcomputers