This document provides an overview of information technology concepts. It begins by outlining the learning outcomes, which are to understand basic computer operations, memory, storage, information systems terminology, and more. It then introduces computers and their widespread use before defining a computer as a programmable machine that processes data. The document describes different types of computers and their uses. It also explains concepts like data representation, the four basic computer operations of input, processing, storage, and output. Finally, it discusses system units, information systems and their elements, and storage technologies like RAM, hard disks, and solid state drives.

1. Department of Information and Communications Technology
Centre for Foundation Studies , IIUM
Revised: 5 April 2023
Overview of IT

2. Learning Outcomes
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At the end of this chapter, you should be able to:
• Identify and explain the basic operations of computing.
• Explain Random Access Memory (RAM).
• Explain the types and characteristics of secondary storage –hard
disk (HDD) and solid-state drive (SSD).
• Explain the definition and elements of Information System (IS)
and other terminologies.

3. Introduction
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• Today, computers are used everywhere in our society. Businesses,
schools, government agencies, and other organizations use
computers and computer technologies to assist day-to-day
transactions, provide better services to customers, and communicate
with others.
• Since computers are widespread within our society today, it is
essential for everyone to know something about computers and to be
a highly efficient and effective computer user.

4. What is a computer?
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• A computer is an electronic device that operates under
the control of stored instructions in its memory. It is a
programmable machine and basically used to capture
and process the data, generate the results, and store the
results for future use.
• Computers are popular because they have the
advantages of speed, reliability, consistency, storage and
communication capabilities.

5. Types of computers
• Supercomputers
• Mainframes
• Midrange computers / servers
• Microcomputers
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6. Supercomputers
• A supercomputer is a high-performance computer that is
commonly used by very large organizations. It is the most
powerful and most expensive computer that leads the world
in the processing capabilities, storage capacity, and accuracy.
• It is used for computing very complex tasks that no other less
powerful computers can handle.
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7. Example of supercomputer
IBM Blue Gene supercomputer
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8. Mainframes
• A mainframe computer has multiple cabinets, each the size of
a large-sized refrigerator called frames on elevated platform
to hide cables and to allow cool air to circulate from beneath.
• The mainframe is designed for batch processing and record -
keeping for processing millions of instructions.
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9. Example of mainframe
IBM mainframe
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10. Midrange computers
• A midrange computer is also referred to as a server. A server
is a central computer that holds collections of data and
programs for connecting or supplying services to many
personal computers (PCs), which are called clients. This entire
connection (network) is called a client-server network.
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11. Example of midrange computer
Figure 1-6: IBM tower server Figure 1-7: IBM blade server
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12. Microcomputers
• A microcomputer is also known as a personal computer (PC).
It is popular in offices, schools and even homes due to its
invention of very small yet powerful microprocessors that
reduce the size and cost of the computers.
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13. Types of personal computers
Desktop PC
Wearable devices: Smart eyewear and Smartwatch
Laptop
Tablet
Smartphone
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14. What is Data Representation?
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Data representation refers to
the internal method used to
represent various types of data
stored on a computer.
Data consist of analog and
digital data, so they
recognize two states only:
on and off. This is known
as the digital data.
Using a binary system to
recognize two states or two
unique digits: 0 and 1, called bits
(binary digits); the smallest unit
of data computer can process.
A group of eight bits is
called a byte.

15. Data Representation (cont.)
Binary representation of electronic states
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FOR INFORMATION ONLY - NOT TO BE ASSESSED

16. Data Representation (cont.) Illustration of character ‘B’ decoded into binary
Step 4: After processing, the binary code
for the capital letter B is converted to an
image and displayed on the output device.
Step 1: The user presses the capital
letter B on the keyboard.
Step 2: An electronic signal for the capital
letter B is sent to the system unit.
Step 3: The signal for the capital letter B is
converted to its ASCII binary code (01000010)
and is stored in memory for processing.
FOR INFORMATION ONLY - NOT TO BE ASSESSED
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17. Data Representation (cont.)
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Representation of word “BYTE”

18. Basic Operation of a Computer
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19. FOUR Basic Computer Operations - INPUT
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• It can be any kind
of data that need
to be entered into
a computer
system.
Definition
• To provide, give
or enter
something (data
or information) to
the
computer system.
Function
• Keyboards,
mouse, scanner,
touch pad, touch
screen.
Example of Devices

20. FOUR Basic Computer Operations - PROCESSING
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• The retrieval or
manipulation of
data to a new
program or
known as an
information.
Definition
• To manipulate the
data into
information
Function
• Central Processing
Unit (CPU)
Example of Devices
*This is 3D model.

21. FOUR Basic Computer Operations - STORAGE
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• The storing or
preservation of
information for
current and later
use.
Definition
• To keep or hold the
data and programs
during and after
processing.
Function
• Primary storage
(temporary/volatile) –
RAM
• Secondary storage
(permanent/non-
volatile) – compact
disk (CD), hard disk
drive (HDD), solid-
state drive (SSD),
thumb drives, flash
memory cards
Example of Devices

22. FOUR Basic Computer Operations - OUTPUT
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• Anything
produced by the
computer system
or the end results
of processing.
Definition
• To generate
result of
processing in
human-readable
form.
Function
• Monitor, speaker,
printers,
headphones, LCD.
Example of Devices

23. The System Unit
The system unit is a case that contains electronic components of the
computer used to process data.
Two important components of the system unit are microprocessors
and memory.
• The microprocessor controls and manipulates data to produce
information.
• Memory is a holding area for data, instructions, and information.
FOR INFORMATION ONLY - NOT TO BE ASSESSED
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24. The System Unit (cont.)
Types of system unit:
Laptop
Tablet Mobile
Device
Desktop
FOR INFORMATION ONLY - NOT TO BE ASSESSED
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25. Information System
• An information system is an organised system for collecting,
manipulating, storing, and processing data into information.
• The goal of an information system is to process data and produce
quality information.
• Most companies will use information system to organise
information to provide better services to their customers.
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26. The Elements of an Information System

27. The Elements of an Information System
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PEOPLE
• People prepare
the procedures
and design the
system.
• People input the
data into the IS
and use the
information
produced by it.
• People build the
hardware and
ensure it runs
smoothly.
PROCEDURES
• The guidelines
and rules for
users to follow
when using an
information
system
• They explain
how tasks must
be done or how
to accomplish
an activity.
HARDWARE
• The physical
tool of an IS.
• All hardware
devices must be
reliable and
capable of
handling the
expected
workload of the
IS.
SOFTWARE
• The non-
physical tool of
an IS.
• The step-by-
step instructions
that tell
hardware how to
perform a task.
DATA
• The
unprocessed
factual items.
• Data are
manipulated by
the software to
produce useful
information that
are requested
by the user.
CONNECTIVITY
• The ability to
communicate
with another
computer or
computer
system.
• A computer
network is the
best way to
have
connectivity in a
company.
*The most
important element.

28. Storage Hardware
• There are two types of storage: primary storage and secondary
storage.
• The three storage hardware are:
• Random Access Memory (RAM),
• Hard Disk Drive (HDD), and
• Solid-State Drive (SSD).
• RAM is a primary storage while the other two are examples of
secondary storage.
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29. Storage Capacity
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It refers to the maximum amount of data (the number of bytes) the
storage can hold. If a file size is 1KB that means, there are about 1000
bytes (1 x 10³). RAM with a capacity of 4GB can hold approximately
four billion bytes.

30. Primary Storage Vs Secondary Storage
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• A computer needs both primary and secondary storage to make it
functional. The differences are:

31. • It holds the data, instructions, and information for current or future
use.
• Two main characteristics of storage are:
• storage medium - the physical material that holds data, instructions, and
information (e.g. disk platter, magnetic tape, electronic circuits).
• storage device - the mechanism that records to and retrieves data from the
storage medium (e.g read/write head, media player/driver).
• Access time is the time taken to complete one reading operation or
one writing operation.
• Transfer rate is the speed of moving the amount of data from
storage medium to RAM or vice versa.
Secondary Storage
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32. Random Access Memory (RAM)
• RAM is the primary storage and is also known as main memory.
• RAM is more expensive than any secondary storage (per unit
storage).
• RAM's capacity depends on the computer type and the
applications to be used on that computer.
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33. Random Access Memory (RAM) (cont.)
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• As you start your computer, the operating system files that reside
in the secondary storage are loaded into RAM and prepare your
computer interface for you to interact with the computer system.
• As you open a file, the data that reside in the computer storage
are transferred into the memory to allow you to work with the
file.
• If you are working on a new set of data, the data are also held in
RAM. However, if you failed to save the newly created data (as a
file) onto secondary storage, you will not be able to retrieve the
file later and it is lost.

34. Hard Disk Drive (HDD)
• Most secondary storage has larger capacities than RAM with much
cheaper costs. Some new computers now come with hard disk
drive (HDD) with a capacity of 1TB.
• A hard disk must be formatted before it can store any file.
Formatting is the process of dividing the disk surface into tracks
and sectors to enable the operating system (OS) to store and read
data on the disk.
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35. Hard Disk Drive (HDD) (cont.)
• Invisible concentric rings called tracks are divided into sectors,
which are the invisible wedge-shaped sections. Two or more
consecutive sectors are combined to form a cluster. For the stack
of platters, cylinders run through the same tracks of multiple
platters.
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36. Hard Disk Drive (HDD) (cont.)
• Contaminants such as hair, dust, smoke particle and dirt may
cause a head crash - the read/write head touches the disk surface
due to the existence of such contaminants.
• Another possible cause could be when the computer is
accidentally dropped while it is still running and as a result, the
read/write heads of the hard disk touch the disk surfaces.
• The scratches on the surface that can cause bad sectors (or areas
on the hard disk that have become damaged).
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37. Solid-State Drive (SSD)
• SSD is a storage that consists of electronic components with no
moving parts. It uses electronic memory or flash memory.
• It can stand shocks/vibrations and durable compared to a hard
disk.
• Initially, SSDs were used only for critical tasks due to the expensive
price. However, now they have become popular in many
applications especially in smartphones and other small, mobile
devices.
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38. Data vs Information
• People are looking for quality information from an information
system.
• Quality information helps us to become more knowledgeable and
can make better decisions.
• Storing, organising, and processing data in a systematic way will
result in quality information.
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39. Data vs Information (cont.)
• Data are raw factual items, such as text and numbers, collected from
various sources.
• Data can be in the form of letters (A-Z, a-z), digits (0-9) and special
characters. Data do not carry any specific meaning unless processed.
• The processed data are called information, where they offer more
meaningful form of data.
• Information is a set of processed data. The processing operation
manipulates the data, according to the program used, to produce
information. Therefore, information is more meaningful to the user than
data and may be useful for decision-making.
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