Lecture 1

MIS & Computer Application

Fall 2010 Lectures -
MBA02093
Instructor: Khurram Khan

Notes Written by: Ali Arshad
17-Nov-2010

2 Fall 2010 Lectures - MBA02093

Lecture 1
Lecture 1 consists of basics about computers. It will contain knowledge like definitions, examples and
information. Let’s start by the definition of computer.

1. Computer: An electronic device that receives data, processes data, stores data, and produces a result
(output).
Computers are made of 2 main parts – hardware and software.

2. Hardware: the tangible, physical equipment that can be seen and touched such as: Computer case,
Monitor, Keyboard & Mouse, Speakers etc...

3. Software: the intangible set of instructions that tell the computer what to do, like programs, software
programs or operating system.

4. Data vs. Information: data refers to symbols that represent facts or ideas... they really don’t mean
anything until they are processed, or put in some sort of context. Then they become information... so
data is raw and information is processed.

5. Program vs. Software:
5.1. A program is a set of instructions written in a programming language to perform a particular
function. Many programs combine together to form software;

5.2. Software refers to a collection of several programs, other procedures and documentation.
Software is also used to perform a task. The most common programming language used for
making software is C and C++. Software is of two types that is system software which is the
operating system and application software. So a program is a set of instructions for performing a
task whereas software is made up of several computer programs. Traditionally software is
purchased on a CD or DVD or is downloaded from the internet; in either case, the software needs
to be installed on a computer before it can be used. There are two type of software. System
software and application software.

6. Types of software:

6.1. Application software -- includes the everyday programs that you use such as Word Processors,
Spreadsheets and Databases. Application software run under System Software, and are made to
do a specific task i.e. (Word Processing etc), which have indirect access to the hardware (i.e.
Behind System Software). There are two types of Application software:General software and
Custom software.

MIS & Computer Application | By ALi Arshad

Fall 2010 Lectures - MBA02093 3

6.1.1. General software are simply off the shelf (which may also include free software)
computer software or hardware, technology, or computer products, which are ready-made
and available for sale, lease, or license to the general public.

6.1.2. Custom software (also known as bespoke or proprietary software) is a type of software
that is developed either for a specific organization or function that differs from or is
opposite of other already available software e.g. off-the-shelf software. It is generally not
targeted to the mass market, but usually created for companies, business entities, and
organizations. Custom software also refers to when companies or governments pay for
customized software for budget or project managing. This software is not targeted for
mass market.

6.2. System Software -- has direct control and access to our computer hardware, and memory
locations. They perform I/O (On/Off) operations on various memory locations, and control the
hardware, to make the application software do a task. Operating systems (OS) are the main
examples for system software. Other examples includeProgramming Languages, Device Driver
Software.Etc…

7. Device Driver:(system software) is a program that lets the operating system communicate with the
computer hardware. Computer parts need a driver because they do not use standard commands. (Ex.: ATI
and Nvidia graphic cards do the same jobs, but not the same way). Many parts need drivers like graphic
cards, modem, network card, sound card, computer printer etc… Some other parts do not need drivers
because they use a kind of standard. The operating system recognizes those parts and knows how to use
those parts. Those include drivers, CD and DVD, Keyboard etc…

8. OS: (Operating system) is System software that allows applications software to communicate with the
hardware. It is a link between Hardware and a user, hardware and hardware, hardware and software,
software and software. In modern era, a computer is useless without an OS. There are two types of
OS:Single Tasking OS and Multi-Tasking OS.



Figure 1: Link between OS and a user

8.1. DOS: (Disk Operating System) is Single taking OS which was the first widely-installed
operating system for personal computers.DOS was (and still is) a non-graphical line-oriented
command- or menu-driven operating system, with a relatively simple interface but not overly
"friendly" user interface. Its prompt to enter a command looks like this: "C :>”. The first
Microsoft Windows operating system was really an application that ran on top of the MS-DOS
operating system. Today, Windows operating systems continue to support DOS (or a DOS-like
user interface) for special purposes by emulating the operating system.

8.2. Windows:Windows is a series of software operating systems and graphical user interfaces. It is a
Multi-Tasking OS.For example, in the most popular OS, Microsoft Windows, it's entirely
possible for a Windows user to be writing a note in a word processor while downloading a file
from the Internet while printing the text of an e-mail message.

9. As we learned in 5.1, a set of instructions that tell a computer what to do is called a program. Further we
discussed in 6.2 that programming languages are a type of system software. Computer programs are
written in programming languages. A person who develops a program is called programmer. The
programmer develops programs to instruct the computer how to process data to convert into information.
A programmer uses programming languages or tools to write programs. Let’s discuss about programming
languages.

10. Programming Languages: A language is a means of communication. We communicate our ideas and
emotions using natural languages like Urdu, English etc. Similarly, a computer language is a means of
communication between a user and the computer.A set of words, symbols and codes used to write
programs is called programming language. Different programming languages are available for writing
different types of programs. Some languages are specifically used for writing business programs, other
are used for writing scientific programs etc. with the help of computer language, a programmer tells a
computer what to do.There are two types of computer programming languages:Low-Level Languages
and High-Level Languages.


10.1. Low-Level Languages:
These languages are near to computer hardware and far from human languages computer can
understand these languages easily. Writing a program in low-level language requires a deep
knowledge of the internal structure of computer hardware. Following are the examples of low
level languages:

10.1.1. Machine language: A type of language in which instructions are written in binary from
is called machine language. It is the only language that is directly understood by the
computer. It is the fundamental language of the computer. Program written in machine
language can be executed very fast by the computer. Programs written in machine
language are machine-dependant. Every computer has its own machine language.
Machine language is difficult to understand. Writing and modifying program in machine
language takes a lot of time. Machine language is also known as first generation
language.

10.1.2. Assembly Language: Assembly language is a low level language. It is one step higher
than machine language. In assembly language, symbols are used instead of binary code.
These symbols are called mnemonics. For example Sub instruction is used to subtract
two numbers. Assemble language is also called symbolic language. Programs written in
assemble language are easier to write and modify than machine language. Assemble
language is mostly used for writing system software. Assemble language is also known as
second generation language.

10.2. High-Level Languages:
A type of languagethat is close to human languages is called high level language. High level
languages are easy to understand. Instructions of these programs are written in English like
words such as inputand print. A program written in high-level language is easy to write and
modify. High-level languages are further divided into following categories: Procedural
languages, object-oriented languages and database query languages.

10.2.1. Procedural Languages: Procedural languages are also known as third generation
languages or 3GL. In these languages, a program is predefined set of instructions.
Computer executes these instructions in the same sequence in which these instructions
are written. Each instruction in this language tells the computer what to do and how to do.

A. FORTAN: FORTAN stands for FORmula TRANslation. It is mainly used for
engineering application and scientific use.

B. BASIC: BASIC stands for Beginner All Purpose Symbolic Instruction Code. It was
created in the late 1960’s. It was used mainly by students to use the computer for solving
simple problems. It is easy to understand. It is widely used for education purpose.


C. PASCAL: This language is used for both scientific and business applications. Its name
was assigned in the honor of French mathematician Pascal.

D. C: C language is a popular high level language. It was developed by Dennis Richie at
AT&T Bell Laboratories in 1972. It was written as part or UNIX operating system. It is
also known as middle-level language because it provides the facilities to write
application software as well as system software.

10.2.2. Object-Oriented Languages: OOP is a technique in which programs are written on the
basis of objects. An object is a collection of data and functions. Object may represent a
person thing or place in real world. In OOP, data and all possible functions on data are
grouped together. Object oriented programs are easier to learn and modify. C++ and
Java are two most popular object-oriented languages. OOP is based on real word
modeling. As in real world; things have properties and working capabilities. Similarly,
objects have data and functions. Data represents properties and functions represent
working of objects. A person can be an example of an object. It has some properties or
characteristics that describe what it is. Some properties of person object can be as
follows: • Name • Age • Height… The person object also has some functions that
describe what it can do. Some functions of person object can be as follows: • Walk or
Talk • Eat.

10.2.3. Database Query Languages: database is a collection of related data in an organized
way. Database query languages are used to retrieve, insert, update, delete or search data
from databases. These are non-procedural languages. Non-procedural languages are
also known as fourth generation languages or 4GL. In non-procedural languages, user
only needs to tell the computer what to do, not how to do. Most popular database query
language is SQL (Structured Query Language).

11. Language Processors/Translators: Computer understands only machine language. A program written
in high-level or assemble language cannot be run on a computer directly. It must be converted into
machine language before execution. Language processor or translator is software that converts these
programs into machine language. Every computer has its own translators. Different types of language
processors are: • Compilers • Interpreters.
11.1. Compilers: A compiler is a program that converts the instruction of a high-level language into
machine language as a whole. A program written in high-level language is called source
program. The program converts source program in machine code called object
program.Theobject program can be executed many times. The compiler checks each statement in
the source program and generates machine instructions. Compiler also checks syntax errorsin the
program (We will discuss syntax errors in next point). A source program containing an error
cannot be compiled. A compiler can translate the programs of only that language for which it is


written for. For example, C compiler can translate only those programs that are written in C
language. In a sentence, Compiler spends some time evaluating the entire program and then
translates all the programming statements of a program into a machine language program, which
is then executed at once.

11.2. Interpreter: An Interpreter is a program that converts one statement of a program into machine
at one time. It executes this statement before translating the next statement of the source program.
If there is an error in the statements, the interpreter stops working and displays an error message.
The advantage of interpreters over compilers is that an error is found immediately. So the
programmer can correct errors during program development. The disadvantage of interpreter is
that it is not very efficient. The interpreter does not produce an object program. It must convert
the program each time it is executed. Visual Basic uses interpreter. In a sentence, Interpreter
translates interactively each programming statement into an immediately usable machine
language instruction. Although an interpreter slows down the execution speed of a program
somewhat, it does not require extra steps to compile and link like a compiler.

Figure 2: Difference between Compiler and Interpreter

12. Programming Errors: Whena program is not written correctly, it gives an error. An error can disrupt
program flow, create nonsensical results or cause a program to terminate completely. Understanding the
differences between syntax errors and logical ones helps the debugging process by making error location
a simpler task. Neither type of error is confined to programming. Let’s learn about these errors.

12.1. Syntax Errors: Syntax Error occurs when the code isn't formatted or typed correctly i.e. in
Python(a programming language), typing “If” instead of “if” gives an error because it only


recognizes lowercase. So we can also say that syntax errors are errors in spelling and grammar.
As a result the code fails to compile (Error message from compiler). We can use the compiler or
interpreter to uncover syntax errors but we must have a good working knowledge of error
messages to discover the cause of the error.

12.2. Logical Errors: Logical Error occurs when there is a fallacy of reasoning i.e. in Python(a
programming language), typing “if x < 0” and “x > 5”. Since a value can't be less than 0 and
greater than 5, a logical error will occur. So we can say that these are the errors that indicate the
logic used when coding the program which failed to solve the problem. We do not get error
messages with logic errors. Our only clue to the existence of logic errors is the production of
wrong solutions. The main difference between Syntax and logical error is; when there is a syntax
error, the program will crash. But when there is logical error the program will not crash but will
give unexpected output. For Example: A syntax error means that a language was used incorrectly,
if you forget to put certain symbols in source code, the machine will not be able to read it. A logic
error means though the language was used correctly, there was a misunderstanding: if you want a,
where (b= c + a) and you give a = b-a instead of a = b-c, then you will get the wrong answer, but
have used the correct language.

12.3. Runtime Errors: A runtime error is a computer error that appears in the form of a message box
consisting of a particular code along with its corresponding definitions. Usually, a user will notice
that the computer becomes noticeably slow before a runtime error appears. Runtime Error occurs
at run-time. Such errors cause a program to end unexpectedly or even cause system shut-down.
Such errors are hard to detect. For example error caused due to low system memory or something
divided by zero, 44/0. Runtime errors indicate bugs in the program or problems that the designers
had anticipated but could do nothing about. For example, running out of memory will often cause
a runtime error. The runtime or run-time error message can also be caused by: Confliction with
TSR (Terminate & stay resident) or other running program, Software issue, Computer Virus,
Memory issue etc.

13. Debugger: Even the most experienced software programmers usually don't get it right on their first try.
Certain errors, often called bugs, can occur in programs, causing them to not function as the programmer
expected. Sometimes these errors are easy to fix, while some bugs are very difficult to trace. This is
especially true for large programs that consist of several thousand lines of code. Fortunately, there are
programs called debuggers that help software developers find and eliminate bugs while they are writing
programs. Adebugger tells the programmer what types of errors it finds and often marks the exact lines of
code where the bugs are found. Debuggers also allow programmers to run a program step by step so that
they can determine exactly when and why a program crashes. Advanced debuggers provide detailed
information about threads and memory being used by the program during each step of execution. In few
words, debugger is a special program used to find errors (bugs) in other programs. A debugger allows a
programmer to stop a program at any point and examine and change the values of variables.



14. Printer: A printer is an output device that prints characters, symbols and graphics on paper. The printed
output is called hard copy. Print resolution is commonly measured in Dots Per Inch (DPI). Different
categories of printers are as follows:

14.1. Impact Printers: An impact printer works like a typewriter. It prints characters or images by
striking a print hammer or wheel against an inked ribbon. Dot matrix, Daisy wheel and line
printers are examples of impact printers. Let us discuss them in little detail.

14.1.1. Dot Matrix Printer: ADot Matrixprinter is am impact printer. It produces printed image
when tiny pins on a print head strike an inked ribbon. When the ribbon presses against
the paper, it creates dots that form characters and graphics. The print head on a dot matrix
printer can contain nine to twenty-four pins. This number of pins depends on the
manufacture and the printer model. A higher number of pins print more dots that produce
higher quality. Overall dot matrix printers do not provide high quality output. They
produce a lot of noise while printing. The printing cost of these printers is extremely
cheap.

Figure 3: How Dot Matrix Printer prints

14.1.2. Daisy Wheel Printer: Daisy wheel printer is similar to a typewriter. It uses a print
wheel. The print wheel is called Daisy Wheel. Each petal of daisy wheel contains
character. A motor rotates the wheel. A hammer strikes a petal against the ribbon when
the desired character reaches the position on the paper. This prints the character on the
paper. Daisy wheel printer is slower then dot matrix printer but better in quality.



Figure 4: Daisy Wheel

14.1.3. Line Printer: Line printer is a fast impact printer. It prints an entire line at a time. Its
speed is measured in Lines Per Minute (LPM). Many line printers can print 3000 lines
per minute. Two types of line printers are Band Printers and Chain Printer. It is
normally used by mainframe and microcomputers.

Figure 5: Green Bar Paper

14.2. Non-impact Printers: A Non-Impact Printer prints character and graphics on a piece of paper
without striking the paper. Some of these use spray ink while others use heat and pressure to
create images. These printers are faster than impact printers. Inkjet, thermal and Laser printers are
the examples of non-impact printers.

14.2.1. Laser Printer: Laser printers are non-impact printers. Its working is similar to a
photocopying machine. The laser printer creates image on the paper by laser beam.
LASER stands for Light Amplification by Stimulated Emission of Radiation. Laser



throws magnetic material powder on paper in the form of microscopic dots. The density
of these dots ranges from 300 to 2000 Dots Per Inch (DPI).The printing speed of laser
printers is from 5 to 300 Pages Per Minute (PPM). Laser printers are also called Page
Printers. They print complete page at a time. Laser printers produce very high quality
print. They are faster than inkjet and dot matrix printers. Color printing with laser printer
is very costly. Laser printers are mostly used in business fields.

14.2.2. Inkjet Printer: An Inkjet printer is a type of non-impact printer. It prints characters and
graphics by spraying tiny drops of liquid ink on paper. These printers can produce quality
text and graphics in both black-and-white and color. Inkjet printers are slower than laser
printers. They can print 1 to 6 pages per minute. Its print quality is higher than dot matrix
printer. They are also relatively inexpensive. Most inkjet printers have usually two print
cartridges: one containing black ink and the other containing color. Another type of inkjet
is also known as Bubble Jet Printer.

14.2.3. Thermal Printer: Thermal printeris a printer that uses heat process to transfer colored
dyes or inks to the paper. Thermal printer is the best color printer currently available but
it is also very expensive. It was originally used only in scientific labs to record data. Now
this printer is widely used to produce very high-quality color artwork and text.
Professional applications requiring very high image quality such as photo studio, medical
labs and security identification systems use thermal printers. The cost of this printer is
thousands of dollars and it prints images in wide ranges or sizes.

15. Monitor: Monitor is the most common output device. The output displayed by monitor is called Soft
Copy. A monitor looks like a television and displays text and graphics. A monitor is also known as
CRT (Cathode Ray Tube),display screen or simply screen. Different display screens are distinguished
on the basis of following Features.

15.1. Size: Monitors are available in different sizes. The standard monitor for personal computer is 15
to 19 inches. The size of monitor is measured diagonally.

15.2. Color: The display screens can be either Monochrome or Color. The color display screens
display output in multiple colors. The color display screens are also called RGB monitors. The
number of colors a monitor can display is called Color Depth or Bit Depth. The RGB display
screens can create 256 colors and thousand of variations of these colors. RGB stands for Red,
Green and Blue. The Monochrome display screens display output in single color. Monochrome
display screens show images in a color usually White, Green, Blue, Red or Amber. However,
monochrome monitor can display different shades of one color. The number of shades of one
color that the monitor can display is referred to Gray-Scale.



15.3. Resolution: All characters and images on the display screen are made of pixels or dots. Pixels are
the dots or pictures or picture elements that form images on the monitor. In other words, Pixel is
the smallest unit of an image, basically a single dot on the screen. Resolution of a monitor is the
number of pixels on the screen. It is the image sharpness of a display screen. High number of
pixel means sharper image. Common resolution size is 1024x768.

Figure 6: The CRT electron gun “shoots” 3 electrons at the screen representing the amount of RGB for the pixel

15.4. Video Display Adapters:A display screen must have a video display adapter attached with the
computer to display graphics. It is also called video graphic card.It is a circuit board that
determines the following things: • Resolution • Number of Colors • Speed with which images
appear on the display screen.

15.5. Refresh Rate: The refresh rate is the speed with which a monitor redraws the image on the
screen. It is also known as vertical scan rateor Vertical Frequency. It is measured in Hertz. It
indicates the number of times the screen is refreshed in one second. Refresh is necessary because
the phosphors hold their glow for fraction of second. The image on the screen appears more solid
if it refreshes rate is high. The screen will flicker less. The refresh rate should be at least 72Hz.
Common monitors have refresh rates between 75 and 85Hz.

15.6. Dot Pitch: The distance between each pixel on monitor is called Dot Pitch.It is also called Pixel
Pitch. The distance between pixels is measured in Millimeters. Many monitors have a dot pitch
of 26 or 28. A smaller dot pitch means that there is less blank space between pixels. A smaller dot
pitch results in better and sharper image.

16. Types of Display Screens: Displayscreens are of two types. These are as follows:


16.1. CRT Monitor: CRT monitor is the most common form of display screen. It looks like a
television. It can display text and graphics. It uses Cathode Ray Tube (CRT). CRT tube creates
an image on the screen by an electronic beam. CRT consists of one or more guns that fire a beam,
of electronics inside the screen. The screen is coated with very tiny phosphor dots from inside.
The beam of electronic repeatedly falls on the surface of screen. Every beam-fall takes only a
fraction of a second. CRT in color monitors consist of three guns. These guns generate Red,
Green and Blue (RGB) colors. The other colors are generated with the combination of these three
colors. A small example is already shown in figure 6. A Monochrome Monitor is a type of CRT
computer display which was very common in the early days of computing, from the 1960s
through the 1980s, before color monitors became popular.Unlike color monitors, which display
text and graphics in multiple colors through the use of alternating-intensity red, green, and blue
phosphors, monochrome monitors have only one color of phosphor (mono means "one", and
chrome means "color"). All text and graphics are displayed in that color. Some monitors have the
ability to vary the brightness of individual pixels, thereby creating the illusion of depth and color,
exactly like a black-and-white television.One of the drawbacks of the monochrome monitor is the
potential for what is known as screen burn. This phenomenon is caused by the relatively high
intensity generated by the single phosphor. When text is left displayed for long periods of time, it
can actually leave an impression on the screen even after the user moves on to view other stored
data. Because the pixels that make up the display on a color monitor are composed of multiple
phosphors, the potential for screen burn with contemporary monitors is greatly reduced,
especially with the use of automatic screen savers and it was the reason why screen savers were
made

.

16.2. Flat Panel Monitors: Laptop PCs use flat panel monitors. These monitors take less space. Flat
panel monitors use variety of technologies. The most common technology is LCD (Liquid
Crystal Display). LCD monitors use much less power than CRT monitor. These monitors are
available in different sizes as 15”, 17”, 18”, 21” and 23”. LCD monitors creates images with a
special type of liquid crystal that is normally transparent but becomes solid when charged with
electricity. LCD monitors are Passive Matrix or Active Matrix. In active matrix display, each
pixel on screen is controlled by its own transistor. It is also called ThinFilm Transistor (TFT)
Monitor. It is much brighter and sharper than passive screens. It is more complicated and more
expensive. It also requires more power. In passive matrixdisplay, two transistors control a whole
row or column of pixels each at the same time. It is also called Dual-Scan Monitor. Its
advantage is that it is less expensive. It uses less power than active matrix displays. The clarity of
image is not sharp.

16.3. Touch Screen Monitors: Touch screen monitors is used for input as well as output. A touch
screen is a special type of VDU (Video Display Unit). It has a grid of beams or fine wires on the



screen. It allows the user to interact with the computer by the touch of a finger rather than typing
on a keyboard or moving a mouse. The user enters data by touching icons or menus displayed on
the screen. Most touch screen computers use sensors to detect touch of a finger. Touch screens is
well suited for simple applications like ATM. It has also become common in departmental stores
and supermarkets. The most popularity of touch screen now days is in Mobile phone industry.

16.4. There is more type of display screens but they are not used for computers. Those include
PlasmaScreens. A plasma display panel (PDP) is a type of flat panel display common to large TV
displays. They are called "Plasma" displays because the pixels rely on plasma cells, or what are in
essence chambers more commonly known as fluorescent lamps. Plasma computer monitors are
less commonly used with computers due to their high operating temperatures, high power
consumption, and fixed resolution. The future of display screens is OLED (Organic Light-
Emitting Diode). An organic light emitting diode (OLED) is a light-emitting diode (LED) in
which the emissive electroluminescent layer is a film of organic compounds which emit light in
response to an electric current. This layer of organic semiconductor material is situated between
two electrodes. Generally, at least one of these electrodes is transparent.OLED (Organic Light
Emitting Display). OLED computer monitors are much thinner and brighter than LCD or Plasma
screens. OLED monitors can also be placed on transparent surfaces, such as glass, allowing the
user to see through them when not active.


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