Computer – it is an electronic device capable of interpreting and performing programmed
instructions. It is an electronic device that accepts input, process data, and stores data and
produces output.
Accepts Input
- Input is whatever is put into a computer system.
Ex. Words and symbols, Numbers afro calculation, pictures, Audio signals
Computer Processes data
Data refers to the symbol that represents facts and ideas
Example on ways that computer processes data;
- Performing calculations, sorting list of words, numbers
- Modifying documents
Computer stores data
Data must be stored so that it will be available for processing. The computer puts
data in one place while it is waiting to be processed and in another place when it is not
needed for immediate processing.
Computer produces Output
Output is the result produced by the computer
Ex. Reports, documents, music, graphs, pictures
History of Computers
Early Computing Device
A. Mechanical Computers
1. Abacus – a wooden object considered as the first counting device, which helped
people add and subtract large numbers.
2. Pascaline – invented by Blaise Pascal which was an adding machine that could
add long columns of numbers.
3. Leibniz Calculator – invented by Gottfried Leibniz which could perform not only
addition but also multiplication through the use of repeated additions.
4. Jacquard’s loom – Invented by Joseph Marie Jacquard, which used punched card
to control the placement of each thread in order to create a design.
5. Arithmometer – invented by Charles Xavier Thomas de Colmar of France, which
was capable of adding, subtracting , multiplying and dividing
6. Difference Engine – Invented by Charles Babbage, which could computer the
difference between two numbers by subtracting one form the other.
7. Analytical Engine – Invented by Charles Babbage and Lady Agusta Ada Byron,
this could process data on its own. It was designed to make decisions.
B. Electromechanical Computers
1. Census Machine – invented by Dr. Herman Hollerith, involved the use of a 3x5
index card which contained encoded information by punching holes on it.
2. Electromechanical Accounting Machine (EAM) – used punched cards
3. Automatic Electronic Digital Computer (ABC) – first automatic Computer
Generation of Computers
First Generation : Vacuum Tube
Vacuum Tubes were used as the internal components of the computers
- Enormous, taking up entire rooms, very expensive to operate, used lots of
electricity, generated lots of heat which caused malfunctions
Ex. EDVAC, ENIAC, UNIVAC
Second Generation: Transistors
Transistors transfer electric signals across a resistor, signals represents sound,
picture some piece of data. Transistors allows computer to become smaller, faster,
cheaper, more energy –efficient and more reliable.
Example PDP8, IBM604, Honeywell 400
Third Generation: Integrated Circuit
IC is a complete electronic circuit on a small chip of silicon
Example IBM 360
Fourth Generation: Microprocessor
Microprocessor is a specialized chip for computer memory and logic
Examples – Apple computer and IBM PC
Fifth Generation
Computers as powerful, intelligent which could copy human expert’s decision and
problem solving thought process, translate ordinary human commands into a language
computers can understand and move and relate to objects as humans. Ex. Robot
Classification of Computers
COMPUTER
1. Microcomputer is a single-user computer which is small enough to fit on a desk
or under a table, also known as personal computers
Types of Microcomputers PDA (Personal Digital Assistant) Handheld PC Laptop or
notebook Desktop/Personal computer
2. Minicomputer is somewhat more powerful than a microcomputer and can carry
out the processing tasks for several people,
3. Mainframe large, fast and fairly expensive, generally used by business and
government to provide centralized storage, processing and management for
large amounts of data,
Applications of Mainframe country-wide credit card transactions and billing
information, census, aerospace research, banking institutions
4. Supercomputer large, extremely fast and expensive used to manage vast
amounts of data that must be processed very rapidly,
Applications of Supercomputers physics, weather forecasting, climate research,
engineering simulations, nuclear research, oil exploration
The Computing Process
1. End-User/ Peopleware
People who use computers and programs written by other people, they are the receiving
end of the so-called “computer line
2. Hardware refers to the physical components of a computer 3. Software refers to the
planned, step-by-step instructions that tell a computer what to do
a. Input Devices act like the “eyes and ears”, accept data in a form that the
computer can use and send these data to the processor
Ex. of Input Devices are; keyboard, mouse, glidepad, touch screen, scanner, digital
camera, barcode reader, remote control, joystick, webcam
b. Processor the processor accepts data from the input devices, it contains the
electronic circuitry to manipulate data and helps carry out instructions or
commands in order to perform various
c. Output Devices display, or show processed results in a form we can use and work
Ex. of Output Devices monitor, printer, plotter, projector, speaker, headset
d. Storage Devices
 Primary Storage is also known as memory, holds input data before it is
processed, contains the programs needed by the processor
 Secondary Storage offers longer storage time and bigger capacity to hold data
permanently Examples Diskette, hard disk, magnetic tape, compact disk,
memory card or flash memory
3. Software refers to the planned, step-by-step instructions that tell a computer what to do