This document provides an overview of a 4-week introductory module on computers. It will cover identifying computer components, outlining the origin and evolution of computers, and evaluating different computer types. Week 1 focuses on introducing computers and their basic components. A computer is defined as an electronic device that can accept data as input, process it, produce output, and store results. The core components that enable these functions are then described, including input devices, the processor, memory, output devices, and storage devices. Examples of common input and output devices are also listed.

1. Prelim Period
(4 Weeks)
At the end of this module, you will be able to:
1. Identify the components of computer system.
2. Outline the origin, evolution and generations of computer.
3. Evaluate the different types of computer.
Week 1 (Topics)
Introduction to Computers
What is a Computer?
Computers are everywhere: at work, at school, and at home. In the workplace, employees use computers
to create correspondence such as e-mail messages, memos, and letters; manage calendars; calculate
payroll; track inventory; and generate invoices. At school, teachers use computers to assist with classroom
instruction. Students use computers to complete assignments and research. People also spend hours of
leisure time using a computer. They play games, communicate with friends and relatives online and using
e-mail, purchase goods online, converse in chat rooms, listen to music
or radio broadcasts, watch or create videos and movies, read books and magazines, share stories, research
genealogy, retouch photos, and plan vacations. At work, at school, and at home, computers are helping
people do their work faster, more accurately, and in some cases, in ways that previously would not have
been possible.
A computer is an electronic device, operating under the control of instructions stored in its own
memory, that can accept data (input), process the data according to specified rules (process), pro-
duce results (output), and store the results (storage). Generally, the term is used to describe a collection
of electric, electronic, and mechanical components known as hardware. While a collection of programs,
application, and even operating system is known as software.
Computers perform four basic operations — input, process, output, and storage. These operations
comprise the information processing cycle. Collectively, these operations process data into information
and store it for future use.
A computer derives its power from its capability to perform the information processing cycle with amazing
speed, reliability (low failure rate), and accuracy; its capacity to store huge amounts of data and
information; and its capability to communicate with other computers.
For a computer to perform operations, it must be given a detailed set of instructions that tells it exactly
what to do. These instructions are called a program, or software. Before processing for a specific activity
begins, the program corresponding to that activity is stored in the computer. Once the program is stored,
the computer can begin to execute the program’s first instruction. The computer executes one program
instruction after another until the activity is complete.
All computer processing requires data. Data is a collection of unprocessed items, which can include text
(letters and numbers), images (pictures), sound (audio), and video (graphics). Computers manipulate data
to create information. Information conveys meaning and is useful to people. During the output operation,
the information that has been created is put into some form, such as a printed report, or it can be stored on
the computer for future use. This can be done by using instruction called program.
People who use the computer directly or use the information it provides are called computer users, end
users, or sometimes, just users. Users and computer manufacturers can reduce the environmental impact
of computers through green computing. Green computing involves reducing the electricity consumed and
environmental waste generated when using a computer.

2. The Components of a Computer
The six primary components of a computer are input devices, the processor (control unit and
arithmetic/logic unit), memory, output devices, storage devices, and communications devices.
The processor, memory, and storage devices are housed in a box-like case called the system unit. A
peripheral is a device that connects to the system unit and is controlled by the processor in the computer.
Peripherals can include input devices and output devices, as well as some storage devices and
communications devices.
Figure 1 shows how the components of a computer interact to carry out a task. The following sections
describe the types of personal computers and mobile devices, as well as their primary components (input
devices, processor, memory, output devices, and communications devices).
Fig. 1
In Figure 1, most devices connected to the computer communicate with the processor
to carry out a task. When a user starts a program, for example, its instructions transfer from a storage
device to memory. Data needed by the program enters memory either from an input device or a storage
device. The processor interprets and executes instructions in memory and also performs calculations on
the data in memory. Resulting information is stored in memory, from which it can be sent to an output
device or a storage device for future access, as needed.
Input devices
These devices are the carrier of inputs (data that is converted into electrical signals received by the
computer system). There’s a lot of input devices that’s widely used.
These includes (selected devices only):
1. Keyboard – It is a typewriter-style device which uses an arrangement of buttons or keys to act
as mechanical levers or electronic switches. Following the decline of punch cards and paper tape,
interaction via teleprinter-style keyboards became the main input method for computers.

3. Keyboard keys (buttons) typically have a set of
characters engraved or printed on them, and each
press of a key typically corresponds to a single
written symbol. However, producing some symbols
may require pressing and holding several keys
simultaneously or in sequence. While most
keyboard keys produce letters, numbers or signs
(characters), other keys or simultaneous key presses
can produce actions or execute computer
commands.
2. Mouse – a hand-held pointing device that detects two-
dimensional motion relative to a surface. This motion is
typically translated into the motion of a pointer on a display,
which allows a smooth control of the graphical user interface of
a computer.
3. Scanner – produces a softcopy stored in the computer. It is a
device that optically scans images, printed text, handwriting or
an object and converts it to a digital image.
4. Microphone – receives/record sound
5. Joystick - an input device consisting of a stick that pivots on a base and
reports its angle or direction to the device it is controlling. A joystick, also
known as the control column, is the principal control device in
the cockpit of many civilian and military aircraft, either as a center
stick or side-stick. It often has supplementary switches to control various
aspects of the aircraft's flight.
6. Drawing tablet/graphics tablet – (also known as a digitizer, drawing tablet, drawing pad, digital
drawing tablet, pen tablet, or digital art board) is a computer input device that enables a user to
hand-draw images, animations and graphics, with a special pen-like stylus, similar to the way a person
draws images with a pencil and paper. These tablets may also be used to capture data or handwritten
signatures. It can also be used to trace an image from a piece of paper which is taped or otherwise
secured to the tablet surface. Capturing data in this way, by tracing or entering the corners of linear
poly-lines or shapes, is called digitizing.
7. Light pen – use as a control in performing multimedia presentation and
electronic reader
8. Stylus (or stylus pen) is a small pen-shaped instrument whose tip position on
a touchscreen can be detected by the screen. It is used to draw, or make
selections by tapping, on devices with touchscreens such as computers, mobile
devices(smartphones and personal digital assistants), game
consoles, and graphics tablets.
9. Touch pad - a pointing device featuring a tactile sensor, a
specialized surface that can translate the motion and position
of a user's fingers to a relative position on the operating system
that is made output to the screen. Touchpads are a common
feature of laptop computers as opposed to using a mouse on
a desktop, and are also used as a substitute for a mouse where
desk space is scarce. Because they vary in size, they can also
be found on personal digital assistants (PDAs) and some portable media players. Wireless touchpads
are also available as detached accessories.
10. Trackballs - a pointing device consisting of a ball held by a socket containing sensors to detect a
rotation of the ball about two axes—like an upside-down mouse with an exposed protruding

4. ball. Users roll the ball to position the on-screen pointer, using
their thumb, fingers, or commonly the palm of the hand while using
the fingertips to press the mouse buttons.
11. Barcode Scanners or barcode reader is an optical scanner that can
read printed barcodes, decode the data contained in the barcode and
send the data to a computer. Like a flatbed scanner, it consists of a
light source, a lens and a light sensor translating for optical impulses
into electrical signals. Additionally, nearly all barcode readers contain decoder circuitry that can
analyze the barcode's image data provided by the sensor and sending the barcode's content to the
scanner's output port.
12. Webcam – is a video camera that feeds or streams an image or video in real time to or through
a computer to a computer network, such as the Internet. Webcams are typically small cameras that sit
on a desk, attach to a user's monitor, or are built into the hardware. Webcams can be used during a
video chat session involving two or more people, with conversations that include live audio and video.
13. Digicam (digital camera) is a camera that captures photographs in digital memory. Most cameras
produced today are digital and while there are still dedicated digital cameras, many more cameras are
now incorporated into mobile devices like smartphones, which can, among many other purposes, use
their cameras to initiate live video-telephony and directly edit and upload imagery to others.
14. Touch Screen is both an input and output device and normally layered on the top of an electronic
visual display of an information processing system.
Aside from input devices, the most important thing why computer processed data is to produced
information (output or converted signals sent from a computer system). This information is carried out
by output devices.
These are the widely used Output Devices:
1. Monitor – or visual display unit is an output device that displays information
in pictorial form. A monitor usually comprises the visual display, circuitry,
casing, and power supply.
2. Speakers – produces sound.
3. Printers – produce a hardcopy. a peripheral device which makes a persistent
representation of graphics or text, usually on paper. While most output is human-
readable, bar code printers are an example of an expanded use for printers. The
different types of printers include 3D printer, inkjet printer, laser printer, thermal
printer, etc.
4. Projector – is an optical device that projects an image (or moving
images) onto a surface, commonly a projection screen. Most
projectors create an image by shining a light through a small
transparent lens, but some newer types of projectors can project the
image directly, by using lasers. A virtual retinal display, or retinal
projector, is a projector that projects an image directly on
the retina instead of using an external projection screen.
5. Plotters - produces vector graphics drawings. Plotters draw lines on
paper using a pen. In the past, plotters were used in applications
such as computer-aided design, as they were able to produce line
drawings much faster and of a higher quality than contemporary
conventional printers, and small desktop plotters were often used
for business graphics.
6. Facsimile/Fax machine – sometimes called telecopying or telefax (the
latter short for telefacsimile), is the telephonic transmission of scanned
printed material (both text and images), normally to a telephone
number connected to a printer or other output device.

5. Once the data or information has been processed, the user will decide then on what to do with it.
To keep important data or information for future used, it needs to be saved or store. These are
mostly used storage devices.
1. HDD (hard disk Drive) or fixed disk is an electro-
mechanical data storage device that uses magnetic storage to
store and retrieve digital data using one or more rigid rapidly
rotating platters coated with magnetic material. The platters are
paired with magnetic heads, usually arranged on a
moving actuator arm, which read and write data to the platter
surfaces. Data is accessed in a random-access manner, meaning
that individual blocks of data can be stored and retrieved in any
order. HDDs are a type of non-volatile storage, retaining stored
data even when powered off.
Types of HDD:
a.External HDD
b.Internal HDD
2. Floppy disk or floppy diskette (sometimes casually referred to as
a floppy or diskette) is a type of disk storage composed of a thin and
flexible disk of a magnetic storage medium in a square or nearly
square plastic enclosure lined with a fabric that removes dust particles
from the spinning disk. Floppy disks are read from and written to by
a floppy disk drive (FDD).
3. Zip Disk or zip drive a removable floppy disk storage system that was
introduced by Iomega in late 1994. Considered medium-to-high-capacity
at the time of its release, Zip disks were originally launched with
capacities of 100 MB, then 250 MB, and finally 750 MB.
4. Optical Disc: CD/DVD/BRD - is a flat, usually circular disc that encodes
binary data (bits) in the form of pits (binary value of 0 or off, due to lack
of reflection when read) and lands (binary value of 1 or on, due to a
reflection when read) on a special material (often aluminum ) on one of its
flat surfaces.
5. Flash Drive/Pen Drive/Mobile Disk - is a data storage device that
includes flash memory with an integrated USB interface. It is
typically removable, rewritable and much smaller than an optical
disc. Most weigh less than 30 g (1 oz). Since first appearing on the
market in late 2000, as with virtually all other computer memory
devices, storage capacities have risen while prices have dropped.
As of March 2016, flash drives with anywhere from 8 to
256 gigabytes (GB) were frequently sold, while 512 GB and
1 terabyte (TB) units were less frequent. As of 2018, 2 TB flash drives were the largest available in
terms of storage capacity. Some allow up to 100,000 write/erase cycles, depending on the exact type
of memory chip used, and are thought to last between 10 and 100 years under normal circumstances
(shelf storage time).
6. Memory card or memory cartridge is an electronic data storage
device used for storing digital information, typically using flash
memory. These are commonly used in portable electronic devices,
such as digital cameras, mobile phones,
computers, tablets, PDAs, portable media players, video game

6. consoles, synthesizers, electronic keyboards and digital pianos The basis for memory card
technology is flash memory. It was invented by Fujio Masuoka at Toshiba in 1980 and
commercialized by Toshiba in 1987.
7. Video Card (also called a graphics card, display card, graphics
adapter, or display adapter) is an expansion card which generates
a feed of output images to a display device (such as a computer
monitor). Frequently, these are advertised as discrete or dedicated
graphics cards, emphasizing the distinction between these
and integrated graphics. At the core of both is the graphics processing
unit (GPU), which is the main part that does the actual computations,
but should not be confused with the video card as a whole, although
"GPU" is often used as a metonymic shorthand to refer to video cards.
8. Sound Card (also known as an audio card) is an
internal expansion card that provides input and output of audio
signals to and from a computer under control of computer
programs. The term sound card is also applied to external audio
interfaces used for professional audio applications. Sound
functionality can also be integrated onto the motherboard, using
components similar to those found on plug-in cards. The integrated
sound system is often still referred to as a sound card. Sound
processing hardware is also present on modern video
cardswith HDMI to output sound along with the video using that connector; previously they used
a S/PDIF connection to the motherboard or sound card.
Typical uses of sound cards or sound card functionality include providing the audio component for
multimedia applications such as music composition, editing video or audio, presentation, education and
entertainment (games) and video projection. Sound cards are also used for computer-based
communication such as voice over IP and teleconferencing.
9. Touch Memory (or contact memory) is an electronic identification device
packaged in a coin-shaped stainless steel container. Touch memory is
accessed when a touch probe comes into contact with a memory button.
Read and/or write operations between the probe and memory chip are
performed with just a momentary contact. Thousands of reads and writes can
be performed with a single chip and data integrity can last over 100 years.
Touch memory complements such technologies as bar
codes, RFID tags, magnetic stripe, proximity cards and smart cards.
10. Cartridge Tapes or A tape drive is a data storage device that reads and
writes data on a magnetic tape. Magnetic tape data storage is typically
used for offline, archival data storage. Tape media generally has a
favorable unit cost and a long archival stability.
A tape drive provides sequential access storage, unlike a hard disk drive,
which provides direct access storage. A disk drive can move to any position
on the disk in a few milliseconds, but a tape drive must physically wind tape
between reels to read any one particular piece of data. As a result, tape drives have very large
average access times. However, tape drives can stream data very quickly off a tape when the required
position has been reached. For example, as of 2010 Linear Tape-
Open (LTO) supported continuous data transfer rates of up to 140 MB/s, a
rate comparable to hard disk drives.
11. Reel Tapes - is the form of magnetic tape in which the recording medium
is held on a reel that is not permanently mounted in an enclosed cassette.
In use, the supply reel (feed reel) containing the tape is placed on a
spindle or hub; the end of the tape is manually pulled out of the reel,

7. threaded through mechanical guides and a tape head assembly, and attached by friction to the hub of
the second, initially empty take up reel. Reel-to-reel tape was used in earlytape drives for data storage
on mainframe computers and in video tape recorders (VTRs).
12. Smart Cards or chip card, or integrated circuit
card (ICC) is a physical electronic authorization device,
used to control access to a resource. It is typically a
plastic credit card-sized card with an embedded integrated
circuit (IC) chip. Many smart cards include a pattern of
metal contacts to electrically connect to the internal chip.
Others are contactless, and some are both. Smart cards can
provide personal identification, authentication, data
storage, and application processing. Applications include
identification, financial, mobile phones (SIM), public transit, computer security, schools, and
healthcare. Smart cards may provide strong security authentication for single sign-on (SSO) within
organizations. Numerous nations have deployed smart cards throughout their populations.
Theuniversal integrated circuit card, or SIM card, is also a type of smart card. As of 2015, 10.5 billion
smart card IC chips are manufactured annually, including 5.44 billion SIM card IC chips.
Cd – compact disc – saves data in digital format
a. 700mb/80minutes
b. 900 mb
DVD– Digital Versatile disc – saves data in media format (4.7 GB and DL - Dual Layer)
BRD – Blu-ray Disc – a High Definition format
There are two types of Disc:
a. Rewritable – mean that you can use the disc and replace the content multiple times
b. Recordable – the content cannot be replaced or erased.
13. Solid State Drive or SSD - is a new generation of storage device used in computers. SSDs use
flash-based memory, which is much faster than a traditional mechanical hard disk. Upgrading to an
SSD is one of the best ways to speed up your computer.