Basics of Computers, Basics of Computers

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Basics of Computers

Fundamentals of Computers
Lesson 1

Objectives
 Personal Computers
 Hardware and Software structure of computers
 Storage devices
 The evolution of computers.
 The characteristics of different generations of computers.
 The types and classification of computers.

Computers – An Introduction
A computer is defined as an electronic device that accepts input, processes it as per given
Instructions and produces meaningful output. It is a machine that accepts data and produces
information.

What is a Personal Computer?
A personal computer (PC) has a minimum standard configuration consisting of a
keyboard, mouse, hard disk drive, floppy disk drive, two serial ports, microprocessor
board (currently, Pentium series), parallel port and a few add-on facilities for extra
devices such as scanners, modems, sound cards .

Data and Information
Data refers to facts that are gathered and fed to the computer. A computer stores,
retrieves, sends, receives, analyses and synthesises data to produce information.

Organization of Computer

 A general purpose digital computer consists of four major, interrelated subsystems,
namely:
 Input
 Memory
 Processing Unit
 Output
Continued……..

Continued……..
 INPUT
An input device needs to convert the inputs from the ‘human understandable’ form to
digital signals. Input devices include mouse, keyboard, joystick, scanner, graphic pen,
camera, touch screen and so on.
 MEMORY
 Primary Memory
 Secondary Memory Hard Disk
RAM
ROM

Continued…
PROCESSING UNIT
Commonly called the Central Processing Unit (CPU), it is the brain of the computer. It
comprises the Arithmetic Logic Unit (ALU), Control Unit (CU) and built-in memory. It
performs operations on the input data as per the programmed instructions and sends the
results to the output.
OUTPUT
The result produced after processing data has to be converted into human understandable
format, which can either be printed on paper or displayed on the screen. Output devices
include printer, monitor, speakers, plotters and so on.

Measurement of Memory
 Data is stored in memory in 0's and 1’s. The space required to store one digit is a ‘bit’.
Each character of the alphabet can be converted into a series of 8 bits. This is called a
byte. Memory is measured in terms of bytes.
8 bits = 1 byte
1024 bytes = 2 10
bytes = 1 KB (Kilo Byte)
1024 KB = 2 10
KB = 1 MB (Mega Byte)
1024 MB = 2 10
MB = 1 GB (Giga Byte)
1024 GB = 2 10
GB = 1 TB (Tera Byte)

Computer Hardware
 The physical components of a computer comprise the hardware. It is a term that
describes the electrical, electronic, mechanical and peripheral devices.
 Hardware is classified into:
 Input Devices
 Output Devices
 System Unit

Input Devices
 Keyboard
 Mouse
 Scanners
 Microphone
 Joystick

Output Devices
 Monitor
 Printer
 Impact printers
 Non Impact printers

System Unit
 Processing device or CPU
 Motherboard with add-on cards
 SMPS (Switch Mode Power supply)
 Storage devices
 Primary Storage Devices
 Secondary Storage Devices
 Floppy Disk
 Optical disk
 Hard Disk
 Tapes

Computer Software

Utilities/ Hardware Initialisation Software
These type of programs are written by hardware manufacturers or hardware machine
language experts. Driver programs come under this category.
Eg: BIOS, mouse driver, scanner driver, printer driver

Operating System (OS)
 OS is the interface between the user and the hardware.
 It provides a platform to the user to enter commands and initiate action involving
hardware routines, without getting involved in the intricacies of the internal architecture.

Operating System Services
 File system maintenance and file related operations.
 Facilitates multi-tasking (many tasks executed simultaneously).
 Input and Output services.
 Memory management.
 Processor's time allocation in time sharing application.
 Networking services (only in OS supporting networking).

Application Software
They are well designed programs to perform a specific task. They are mainly used to cater
to a specific set of user requirements. Microsoft Office, Internet Explorer, Accounting
software like Tally, Database Management Systems all belong to this category.

Programming Languages
When an application software fails to meet the requirements of the user, he/ she can write
their own software, using a programming language.
Low Level Language
Low level languages are close to the hardware. They comprise instructions which are
directly given in computer-understandable digital code or some pseudo code.
Middle Level Language
This language has syntax, rules and features like high level language, but it can
implement low level language as part of its code.
High Level Language
This is very much like the English language – easy to learn, program and debug.

Translators
Programs written in any programming language need to be converted into machine
language in order to be executed. This task is done by translators.
A Compiler/ Interpreter is a translator which converts a program written in high level
language into machine language with the help of the operating system. The difference
between an interpreter and a compiler is that the interpreter converts the program, line by
line, and reports errors whereas the compiler converts the entire program and reports errors.

Generations of Computers
First Generation (1951-58)
The first electronic computer was built in Pennysylvania University, USA in 1946. It
was called ENIAC.
Second Generation (1959-64)
The second generation computers, which appeared in 1959, had silicon transistors
instead of electronic valves.
Third Generation (1965-70)
In 1964, the Integrated Circuit (IC) replaced the transistors and a new generation of
computers evolved with improved features.
Fourth Generation (1971-85)
In the fourth generation computers were built, a number of silicon chips were used in a
discrete circuit. a single microprocessor chip was used to accommodate the entire
functional circuit.
Fifth Generation (1985 till date)
Computers belonging to the current generation are characterised by artificial
intelligence.

Types and Classification of Computers
 Based on Hardware Structure and Functioning Technology
 Digital Computers
 Analog Computers
 Hybrid Computers
 Based on Size and Power
 Super Computer
 Mainframe
 Mini Computer
 Workstation
 Personal Computer
 Laptop
 Palmtops

Thank You

Basics of Computers, Basics of Computers

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