CS201
Lecture1
Daily usage of Computers:
1. Computers at home : internet, games, home businesses
2. Computers in education : audio visual aid in schools, colleges, libraries. Classroom presentation,
computer labs, distance learning etc.
3. Computers in workplace : record keeping such as accounting, medical, operations etc.,
Ecommerce, communications, production lines: robots etc.
4. Computers outdoor : ATM, GPS, sales catalog, mall picture booth etc.
Computer is an electronic device that accepts an input, process and provides an output.
The four major operations a computer performs are as follows:
Input: provide/feed data into the computer
Processing: computer performs specific operation on data determined by the user or system
Output: computer outcomes the result
Storage: computer stores data, programs as input/output for future use
The above operations are abbreviated as IPOS.
Figure: Flow of operations a computer performs
Hardware and Software:
Hardware:
Physical part of the computer. Hardware can be internal or external.
Internal Hardware: located inside the system unit of the computer. Example: CPU, RAM, processor etc.
External Hardware: located outside of the system unit. Example: keyboard, monitor, printer, portable drive
etc.
Divisions of hardware:
Input Devices: An input device is used to input data into the computer. Example: keyboard, mouse,
joystick etc.
Processing Devices: A processing device performs calculations and comparisons necessary for processing.
The main processing device is the central processing unit (CPU). It is the “brain” of the computer.
Output Devices: An output device presents the results to the user. Examples: monitor, printer, headphone
etc.
Storage devices: Storage devices are used to save data, programs or output. Examples: hard drive, floppy
diskette, CD discs etc.
Communication Devices: Communication devices allow the user to communicate with others and access
remote information. Examples: modem, network card etc.
Software:
The programs or instructions used to tell the computer hardware what to do
Software are written in codes so that computer hardware understand the
tasks to be performed. Software can be installed in the hard drive, or run in RAM or can be assessed from a
remote location.
Two basic types of software: System software and Application software.
