ToC
Week
|
Topic
|
2-3
|
OVERVIEW
OF COMPUTER SYSTEM
· Definition
of computer
· Constituents
of a computer
· Computer
hardware
· Computer
software
· Characteristics
of a computer
|
4
|
DATA
AND INFORMATION
· Definition
of data and information
· Differences
between data and information
· Examples
of data and information
|
5-6
|
COMPUTING
DEVICES 1(Pre-computer age to 19thcentury)
· Features,
components and uses of:
Abacus,
Slide rule, Napier’s bone, Pascal’s calculator, Leibniz multiplier,
Jacquard’s loom, Charles Babbage difference and Analytical engine, Hollerith
machine `
|
7-8
|
COMPUTING
DEVICE II (20TH century to date)
· Features,
components and uses of:
ENIAC,
EDVAC, UNIVAC 1, Desktop PC, Laptop and Notebook computer, Palmtop computer.
|
TOPIC
ONE: OVERVIEW OF COMPUTER SYSTEM
Definition
of a Computer
A
computer can be defined as an electronic machine (device) which under the
control of a stored program accepts data, stores the data, processes the data
and brings out the results as information.
Computer
as an IPOS system
Computer
performs 4 key operations on data
a. Input b. Processing c. Output d. Storage
Input: data are
entered into the computer through the input unit. Data are raw facts that are
to be processed into meaningful form.
Processing: Computer
performs certain operations on data entered into it; the Central Processing
Unit (CPU) handles this operation.
Output: The result of
what has been processed will be displayed by the output device such as the
monitor.
Storage: Inputted data
and processed information are stored in the memory and permanent storage on the
computer.
Constituents/Components
of a Computer system
The
computer is referred to as a system because it is made up of several components
that work together to enable it function properly. There are 2 main
constituents of the computer system, these are:
·
The hardware
·
The Software
Hardware
These
are the physical components of the computer system. They are the tangible parts
that can be seen and touched. There are two major parts, namely:
§ The system unit
§ The peripherals
System
unit: The
system unit is the rectangular casing that houses (contains) several important
components that controls the operation of the computer system such as the
motherboard, CPU (Microprocessor), RAM, Sound card, video card, CD drive,
Floppy disk drive etc. It also provides interface for connection of the
peripherals.
Peripherals: These are the
devices connected to the system unit for the purpose of input, output and
storage operations. Examples of peripheral devices are keyboard, Mouse,
Monitor, Printer, Scanner, DVD, CD, USB flash drive etc.
Software
The
software is a term used to describe the collection (or set) of programs that
can be run on a computer system. A program is a set of instructions that tells
the computer what to do, when to do it and how to do it.
There
are two types of software, these include:
§ System software
§ Application software
System
software:
This software controls the computer hardware and the internal operations of the
computer system. Examples include Windows OS (Windows XP, Windows ME, Windows
Vista, Windows 7, Windows 8, Windows 10), Linux OS(Redhat, Fedora, Ubuntu
etc.), MAC OS etc.
Application
software: These
are software that enables the user to perform specific operation or task on the
computer. Examples include:
Application
software (packages)
|
Functions / Uses
|
MS
Word, WordPad, WordPerfect
|
Used
for word processing
|
MS
Excel, Lotus1-2-3, Quattro Pro
|
Used
for spreadsheet, calculation and analysis
|
Corel
draw, Paint, Photoshop, PageMaker, Corel Graphics
|
Used
for graphic works
|
Front
page, Publisher, Dreamweaver, cold fusion
|
For
web designing
|
MS
Access, Oracle, Postgre sql, Fox pro, Dbase, Ingress, MySQL
|
For
database management
|
MS
outlook, Outlook express, MS exchange, Sendmail
|
For
email management
|
MS
PowerPoint, Impress, Prezi, Harvard Graphics
|
Used
for presentation of seminars and lectures
|
Maths,
MATLAB, SPSS, Mintab
|
Create
and edit mathematical formulae/statistical analysis
|
Internet
explorer, Mozilla firefox, chrome, Opera mini, UC browser, Netscape
Navigator, Safari , Mosaic,
|
Internet/Web
browsing
|
Characteristics
of a Computer
·
Speed: Computer
performs its data processing operation at a very high speed. The speed of the
computer is measured in Hertz (Hz). A computer with speed rating of Mega Hertz
(MHz) can perform millions of cycle of operation per second.
·
Accuracy: Computer gives
accurate result as long as the correct data is keyed into it.
·
Versatility: computer can be
used to perform various kinds of task e.g. graphic design, word processing, web
development etc.
·
Reliability/Durability: Computers do
not get tired like human; they can work continuously for days and weeks without
any error.
·
Memory and storage: Computer can
store large amount of data and information. The capacity of the memory/storage
device is measured in bytes. A byte is a group of eight bits. A kilobyte (KB)
is 1024 bytes. A megabyte (MB) is 1,000,024 bytes.
·
Programmable: The computer
hardware is useless without the program that controls it. Thus, all tasks and activities
performed by a computer are made possible by means of a program.
·
It
is electronic in nature
TOPIC TWO: DATA AND
INFORMATION
Data
Data
are raw facts and figures without any added interpretation. Data can be defined
as a representation of facts or concepts in a formalized manner which should be
suited for interpretation or processing by human or electronic machine.
Examples of data include:
- Symbols:
$, @, &, /, # etc.
- Figures/Numbers:
1, 2, 34, 0.12 2 etc.
- Alphabets:
A-Z or a-z
- Words:
Tunde, Facts, Ibadan etc.
Information
Information
is an organized or classified data which has some meaningful values for the
receiver. It can also be defined as the processed data on which
decisions are based. Examples of information include:
·
Computer
is a representation of modern life
·
2
x 7 = 14
·
10%
of N1000 = N 100
Sources
of data and information
Sources
of data
Data
are used for information generation and this can be obtained from different
sources. Some of the sources of data include:
·
Observations
·
Questionnaires
·
Interviews,
survey and fieldwork
·
Registrations
·
Experiments
·
Form
filling
Sources
of information
Information
can come from virtually anywhere — media, blogs, personal experiences, books,
journal and magazine articles, expert opinions, encyclopedias, database,
television, newspapers and web pages — and the type of information you need
will change depending on the question you are trying to answer.
Differences
between data and information
Data
|
Information
|
Data
is used as input for the computer system.
|
Information
is the output of data.
|
Data
is unprocessed facts and figures.
|
Information
is processed data.
|
Data
doesn’t depend on Information
|
Information
depends on data.
|
Data
is not specific.
|
Information
is specific.
|
Data
doesn’t carry a meaning
|
Information
must carry a logical meaning.
|
Data
is the raw material.
|
Information
is the product.
|
Data
cannot be used for decision making.
|
Information
is used for decision making
|
Qualities
of good information
·
Relevance: It must be suitable
for the purpose it is required for.
·
Accurate: It be free from
errors
·
Availability: It should be easy
to obtain or access
·
Timely: It should be
available at the right time
·
Comprehensive/Completeness: It should contain
all necessary details
·
Reliability: It should come from
a reliable source.
TOPIC 3: COMPUTING DEVICES I
Abacus
Features
and components
Abacus
was invented around 500 BC. It was made up of strings or wires, frames and
beads. Modern Abacus uses sliding beads in columns that are divided into two by
a center bar. The upper part is called the heaven and each of the two beads
(representing the two hands) is worth 5 when moved to the center. The lower
part is called the “earth”, where each of the 5 beads (representing the 5
fingers) is worth 1 when moved towards the center. The Abacus is really just a
representation of the human fingers.
Use
For
addition and subtraction
Napier’s Bone
Features
and components
John
Napier in 1617 invented the Napier’s bone. The device involves a
collection of moveable numbered rods and a board.
Use
Used
to perform multiplication
Slide rule
Features and components
William
Oughtred invented the slide in 1632. The Slide rule is a mechanical analog
computer. In its most basic form, the slide rule uses two logarithmic scales to
allow rapid multiplication and division of numbers.
Uses
The
slide rule is used mainly for multiplication and division, and also for
"scientific" functions such as roots, logarithms and trigonometry,
but usually not for addition or subtraction.
Pascal’s calculator
Features
and components
Blaise
Pascal invented the Pascal’s calculator otherwise called PASCALINE in 1642. It
is a gear or dial driven (just as that on analogue telephone) calculating
device.
Use
It
could only be used for addition and subtraction operations. It’s use is evident
in odometer and electricity meter.
Leibniz multiplier
Features
and components
Leibniz
multiplier or (Stepped Reckoner) was invented by Gottfried William Leibniz in
1671. It was an improvement on the PASCALINE. It contains a special kind of
gear called “Leibniz wheel”.
Uses
It
could add, subtract, multiply and divide.
Jacquard’s loom
Features
and components
In
1801, Joseph Marie Jacquard invented the Jacquard’s loom. This machine was
controlled by a number of punched cards, put together into a continuous
sequence.
Use
Used
for producing fabrics with beautiful patterns
Difference engine
Features
and components
In
1822, An English mathematics professor called Charles Babbage invented the
Difference engine. It was composed of 25000 parts, weighed 15 tons and stood 8
feet (2.4m) high.
Use
Used
for calculating differential equations.
Analytical engine
Features
and components
In
1832, Charles Babbage designed another machine called Analytical engine which
was deemed to be the first mechanical computer. The machine was steam-powered,
though never completed, outlined the basic elements of a modern day general
purpose computer. It contains input in the form of punched card containing
operating instructions and a "store" for memory of 1,000 numbers of
up to 50 decimal digits long. It also contained a "mill" with a
control unit that allowed processing instructions in any sequence, and output
devices to produce printed results. Augusta Ada, Countess of Lovelace
(1815-1842) created the instruction routines to be fed into the computer,
making her the first female computer programmer.
Use
It
could store 1000 numbers of up to 50 decimal digits long. It was programmable.
Herman Hollerith machine
Features
and components
Herman
Hollerith invented the Herman Hollerith machine which used punch card to store
information which he fed into the machine to compile the results mechanically.
Use
It
was used for collating, sorting and summing the data gotten from 1890 US
census.
Burrough’s
Machine
In
1885, William Seward Burroughs from American Arithmometer company invented this
mechanical adding machine. the early Burroughs models were large machines
characterized by having glass panels in the sides, so the mechanism could be
seen. Common components of the Burroughs machine: keypads, Levers, Registers,
and Printer.
TOPIC
FOUR: COMPUTING DEVICES II
ENIAC
In 1946, John Mauchly and J. Presper
Eckert completed the ENIAC (Electronic
Numerical integrator and Computer). It was the first general purpose
computer. ENIAC contained 18,000 vacuum tubes, weighed 30 tons, occupied 1800
square feet of floor space and required 160 kilowatts of electrical power. The
ENIAC used punched card for input and output. ENIAC was used by US for hydrogen
bomb project and programming.
EDVAC
Features and
components
The
EDVAC (Electronic Discrete Variable
Automatic Computer) is the successor of the ENIAC and was made by the same designers: John
Mauchly and Presper Eckert in 1949.
Unlike
its predecessor the ENIAC, it was binary rather than decimal. It was the
first designed stored program computer with memory capacity of 1000
words (later set to 1,024 words, thus giving a memory, in modern terms,
of 5.5 kilobytes). It contains 6,000 vacuum tubes and consumed 56 KW of
power and covered 490 square feet of floor space.
UNIVAC
1
Features and components
The
UNIVAC 1 (Universal Automatic Computer 1) was invented by John Mauchly
and Presper Eckert in 1951. The machine was 25 feet by 50 feet in length,
contained 5,600 tubes, 18,000 crystal diodes, and 300 relays and had an
internal storage capacity 1,000 words or 12,000 characters. It
utilized a Mercury delay line, magnetic tape, and typewriter output. Magnetic tape was still used for input and
output. It was the first commercial computer.
Assignment
State
the features and components of the following devices
·
Desktop
Personal Computers
·
Laptop
and Notebook Computers
·
Palmtop
computers
TOPIC
5: INPUT DEVICES
These
are the hardware devices that are used for entering data and instructions into
the computer system. The input devices allow human to interact with the
computer system. The following are some examples of Input devices:
Keyboard: Most important input
device. The keyboard is very much like a typewriter keyboard with a few
additional keys. The keys when pressed send an input signal into the
computer.
Mouse: A mouse is a small
object you can roll along a hard or flat surface. It controls the
movement of the cursor on a display screen.
Light
pen:
An input device that utilizes a light-sensitive detector to select, create and
modify object on a display screen.
Touchpad: A touchpad is used
for pointing on a computer display screen. It works by sensing the user’s
finger movement and downward
pressure. It is often rectangular in shape and found mostly on laptops. It is an alternative to
mouse.
Touch
screen: It
allows the user to operate / make
selections by simply touching the display screen. The display screen is
sensitive to touch of a finger or stylus. Widely used on ATM machines and most
mobile phones.
Microphone: A device that is
used to capture and record
sound.
Bar
code reader:
These are photoelectric scanners that read bar codes printed on product
containers. They are generally
used in super markets.
Scanner: Scanner reads texts,
images or illustrations printed on paper and translate the information into a form that the computer can use.
It works by digitizing an image.
Magnetic
Ink Character Recognition (MICR): MICR can identify character printed
with a special ink that contains particles of magnetic material. This
device is widely used in banking industry.
Optical
Mark Recognition (OMR): Also called mark sense reader is a
technology where an OMR device senses the presence or absence of a mark,
such as pencil mark. OMR is widely used in tests such as aptitude test.
Joystick: Is an input and
pointing device used in computer games.
Digital
camera:
An input device used to capture images and moving pictures.
Differences
between Mouse and Keyboard
Keyboard
|
Mouse
|
Used
to enter instructions
|
Used
to point and select
|
Keys
are pressed
|
Buttons
are clicked
|
Combination
of keys can be pressed
|
Left
or right button is clicked
|
Cannot
drag and drop text
|
Drags
and drops text
|
It
has keys
|
It
has buttons
|
Requires
no mouse pad
|
Requires
a mouse pad
|
Assignment
List
and briefly explain ALL set of keys on the keyboard. Hint: Alphabet keys
