FIRST TERM E-LEARNING NOTE
SUBJECT: DATA PROCESSING CLASS: SSS1
SCHEME OF WORK
WEEK TOPIC
INTRODUCTION TO DATA PROCESSING
HISTORY OF COMPUTING
HISTORY OF COMPUTERI.
HISTORY OF COMPUTER II.
CLASSIFICATION OF COMPUTERSI.
CLASSIFICATION OF COMPUTERSII.
DIGITALIZATION OF DATAI.
DIGITALIZATION OF DATAII.
ICT APPLICATION IN EVERYDAY LIFE
DATA AND INFORMATION
REVISION
EXAMINATION
REFERENCES
Data Processing forSenior Secondary Education by Hiit Plc.
A Handbook on Computer Studies by NiyiAdekolegan.
On-line Materials.
WEEK ONE
TOPIC: INTRODUCTION TO DATA PROCESSING
In this chapter, you shall learn about what is data and information; the difference between data and information. Attempt to distinguish between manual and electronic data processing.
DEFINITION OF DATA
The term data means any basic fact which may be input to some processing system. A processing system is one where computations, comparisons and general manipulation of data are done. The processing may be people or machine e.g the computer.
Information on the other hand, is the end – result of a processing system. The information is needed by management for decision making. The relationship between data and information is shown in the diagram below:
INPUT PROCESSING OUTPUT
WHAT IS DATA PROCESSING?
Data processing is the task of using a collection of basic facts to produce information, usually it has no value in itself until it is subjected to analysis, validations and comparisons with other data produce result (information), for example a collection of weights of individuals do not turn useful information for decision making.
However when the set of data is processed such as searching for individual with a maximum or minimum weight or the weight of all concerned in the study, information is produced.
Management can decide on the basis of each information to assign special duties to the fellow with the maximum or minimum weight. Other use could be made on such information depending upon the situation prevailing on the organization and their special needs.
Therefore, data processing is an operation on computer data which involves the entering, sorting, updating and retrieving of information using computer.
PROPERTIES OF DATA
Collected/Captured
Prepared
Presented
Precise
Complete
Accurate
Purposeful
Assigned
DATA PROCESSING CYCLE
The data processing cycle describes the stages of data processing. It involves the following stages:
Data gathering
Data collation
Input stage
Processing stage
Storage stage
Output stage
Element of data processing;
INPUT PROCESSINGOUTPUT
Data is often required for various purposes. Even the same item of data may be used in a great variety of ways depending upon the user’s objectives.
Most data processing work may be viewed as consisting of data, processor and output. Usually, storage also features since both data and program instructions need to be stored.
EVALUATION
Differentiate between data and information
Define data processing
DATA PROCESSING ACTIVITIES
Data processing activities involve the following:
INPUT: involves three steps; collection, verification/validation and coding
PROCESSING : involves classification, sorting, calculating, converting and storing
OUTPUT: involve retrieving, converting and communication.
INPUT ACTIVITY
COLLECTION: involves gathering data from various sources and assembling it at one location.
VERIFICATION/VALIDATION: after data have been gathered, its accuracy and completeness must be checked. This is an important step that helps to eliminate the possibility of Garbage-In – Garbage-out(GIGO)
CODE: data must be converted into machine readable form so that it can be entered into the processing system. Entering data via a computer terminal and keyboard is one example of coding.
PROCESSING ACTIVITY
a) CLASSIFICATION: Classification involves categorizing data according to certain characteristics to make it meaningful to the user. For example, sales data can be grouped according to salesperson, product type, customer or any other classification useful to management.
b) SORT:This involves arranging the grouped data element into predetermined sequence to facilitate processing. For example, an employee number can be last. Sorting can be done on numbers, letters, special characters or a combination of them.After it hasbeen classified, data may be stored.
c) CALCULATION: The arithmetical or logical manipulation of data is referred to as calculation. Examples include computation of students’ grade –point averages, customers’ bank balances and employee’s wages.
d) SUMMARISE:reducing large amount of data to concise, usable form is called summarizing. The logical reduction of data is necessary to provide information that is useful.
e) STORE: this involves the storing of data not immediately needed;data could be stored on a disk, tape or CD-ROM.
OUTPUT ACTIVITY
This involves retrieving data, printing data and data communication.
IMPORTANCE OF DATA PROCESSING
The art of management is increasing as our society becomes more competitive and more technologically advance. The volume of data being generated is correspondingly increasing and becoming unmanageable. On the other hand, the need to make information available, timely and accurately is becoming more vital in the competitive world in which we have found ourselves. It is when a large volume of data is required to be processed speedily and accurately that Data Processing becomes indispensable.
GENERAL EVALUATION
What is data processing?
Describe a typical data processing cycle.
Describe what is involved in each stage of data processing.
Why is computer a better tool for data processing?
Discuss why data processing is important in business organization.
READING ASSIGNMENT
Data Processing For Senior Secondary School ByHiit.
WEEKEND ASSIGNMENT
……….is a basic fact that needs to undergo processing.
A. information B. data C. output D. input
The methodology of converting data into information is
A. data and information B. data processing C. decision making D. none of the above
The major reason for data processing is A. decision making B. conflict promotion
C. information generation D. data manipulation
In data processing, input activity involves A. collection B. verification
C. retrieving D. all of the above.
One of these is not data property
A. presentation B. collection C. misuse D. accuracy
THEORY
What is data processing?
Describe and explain a typical data processing cycle.
WEEK TWO
TOPIC: HISTORY OF COMPUTING
EARLY MECHANICAL COUNTING/CALCULATING DEVICES
Abacus
Slide rule
EARLY ELECTRO-MECHANICAL COUNTING DEVICES
John Napier bone
Blaize Pascal machine
Gottfried Leitbnitz machine
Joseph Jacquard Loom
Charles Babbage analytical machine
EARLY ELECTRONIC COUNTING DEVICES:
Herman Hollerith punch card
John Von Neumann machine
Man has put in every effort to have better methods of calculations. As a result of man’s search for fast and accurate calculating devices, the computer was developed. Essentially, there are three kinds of calculating devices: manual, mechanical and automatic.
ABACUS
The first calculating device was probably Abacus. The Chinese invented it. It is still in use in some countries because of its simple operation. It is made up of a frame divided into two parts by a horizontal bar and vertical threads. Each thread contains some beads. It was used to calculate simple addition and subtraction.
NAPIER’S BONE
The need for a better calculating device was felt as time passed. John Napier, a Scottish mathematician, invented a set of eleven rods, with four sides each which was used as a multiplication tool. These rods were made from bones and this was the reason why they were called Napier Bones. The rods had numbers marked in such a way that, by placing them side by side, products and quotients of large numbers can be obtained.
EVALUATION
Explain types of early counting devices.
How does Abacus and Napier’s function.
PASCALINE
The first mechanical calculating machine was invented in 1642, by Blaize Pascal, a French mathematician. Numbers were entered by dialling a series of numbered wheels in this machine. A sequence of wheels transferred the movements to a dial, which showed the result.
Through addition and subtraction were performed the normal way, the device could perform division by repeated subtraction and multiplication by repeated addition.
LEIBNITZ CALCULATING MACHINE
Gottfried Wilhelm Von Leibnitz invented a computer that was built in 1694. It could add and after changing some things around, it could multiply. Leibnitz invented a special stepped gear mechanism for introducing the added digits and this is still being used.
JACQUARD’S LOOM
Jacquard’s loom was one of the first machines that were run by a program. Joseph Jacquard changed the weaving industry by creating a loom that controlled the raising of the thread through punched cards. Jacquard’s loom used lines of holes on a card to represent the weaving pattern.
PUNCHED CARD
During the years1920 and 1930, the punched card system developed steadily. A standard card was divided into 80 columns and 12 rows. Only one character could be represented in the 80 columns, thus providing a maximum of 80 characters per card. Punching one, two or three holes in any one column represented a character. Holes were punched into a blank card by a punch machine whose keyboard resembled that of a typewriter.
CONCLUSION
We have learnt about the various calculating devices and the various ways they perform their operations. We learnt also that Abacus was the first calculating devices.
NUMBER SYSTEM (REVISION)
To effectively use the computer, it is therefore necessary to know how data is represented and communicatedto it. There are different ways of representing data in the number system, namely:
Decimal System
Binary System
Octal System
Hexadecimal Number System.
GENERAL EVALUATION
How does Abacus and Jacquard’s loom function?
What type of operation can Pascaline perform?
Explain the four number system.
List any four early counting devices.
READING ASSIGNMENT
Read Chapter 1, Pg1-3, A Handbook On Computer Studies, By NiyiAdekolegan.
WEEKEND ASSIGNMENT
Napier’s Bones had ……..A. 9 rods B. 11 rods C. 10 rods D. 12 rods
Jacquard’s loom was used in the ……A. mechanical industry B. weaving industry C. food industry D. all of the above
……. was the first calculating device. A. Napier’s Bones B. Punched card C. Abacus D. Slide rule
The octal number system has a radix of ……. A. 7 B. 10 C. 16 D. 8
The Decimal Number is in Base ……A. 2 B. 8 C. 10 D. 16
THEORY
Describe a standard Punch Card.
Explain Decimal Number system.
WEEK THREE
TOPIC: GENERATIONS OF COMPUTERS
FIRST GENERATION
Electronic machine which was distinct from mechanical computers evolved about 1945. UNIVAC is a good example of this generation of computers.
Computers of this generation were characterized by:
They used Vacuum tubes.
They were very large and expensive.
They were very bulky.
They had a low retentive memory.
They generated a lot of heat.
SECOND GENERATION
Second generation computers were the replacement of vacuum tubes. Second generation computers utilized primary discrete TRANSISTORS. They had limited capability but were more advanced than the first generation computers.
FEATURES
They were more reliable than the first generation.
They could perform calculations.
They had a more efficient storage facility.
They generated lesser heat compared with the first generated computers.
THIRD GENERATION
Third generation computers utilized INTEGRATED CIRCUIT [ICs] technology, Small Scale Integration [SSI] with more sophisticated software capability like multi-programming, multi-processing and operating systems as resource managers.
The following can be noted in third generation computers:
Faster input and output.
Increased storage capability
Increased process capability
Ability to display pictures and musical sound
CONCLUSION
We have learnt that the first generation computers used vacuum tubes, second generation computers used TRANSISTORS while the third generation computers used integrated circuits.
EVALUATION
Mention the characteristics of first generation computers.
What did the second generation make use of?
FOURTH GENERATION
Fourth generation computers appeared at about 1975. The technologies that characterized these machines were LARGE SCALE INTEGRATION (LSI) and VERY LARGE SCALE INTEGRATION (VLSI). The computers produced at this period were of a higher capability in terms of speed, storage and of superior performance over their counterparts of the third generation.
FIFTH GENERATION
These generations of computers made use of ARTFICIAL INTELLIGENCE (AL). This category of computer was built around the following objects.
To build super computer i.e computers which could perform operation in the range of 10 billion instructions per seconds.
They were designed to have capacities like sight and hearing as well as capability to stimulate human thoughts e.g robots.
CONCLUSION
We have learnt features of the fourth and fifth generations of computers i.e the fourth generation used Very Large Scale Integrated (VLSI) and ARTIFICIAL INTELLIGENCE (AL)
EVALUATION
What did the fourth generation use?
Fifth generation computers is built on what technology?
GENERAL EVALUATION
The first generation uses …… as its circuitry.
List four features of the second generation computer.
What is the difference between AI and Expert system?
VLSI means ……….
READING ASSIGNMENT
Read Chapter 2, Page 9-10, A Handbook On Computer Studies, By NiyiAdekolegan.
WEEKEND ASSIGNMENT
Fourth generation computers made use of …………A. VLSI B. Transistors C. AI
Fifth generation made use of ……………… A. AI B. Vacuum tubes. C. SSI
……..is an example of computers in the fifth generation A. Robort B. UNIVAC C. AI
How many generations of computers do we have? A. 4 B. 5 C. 6 D. 9
The fourth generation of computers came on board in the year…….A. 1957 B. 1975 C. 1997 D. 1990
THEORY
Give the full meaning of the following acronyms:
IC
VLSI
SSI
LSI
AI
Explain the Fifth generation computers.
WEEK FOUR
TOPIC: HISTORY OF COMPUTERS
Consider the table below:
Generations
Of computers
Year of
development
The
Technology
Used
Characteristics
Software
Instruction
Storage
Capacity
First
1951-1958
Vacuum tube
Very big and slow in operation
Machine language
Small internal storage
Second
1959-1964
Transistor
Less heat generation
High level &
Assembly
Core storage
Third
1965-1975
100-1000
Chips
Introduction of integrated circuit
Multiprogramming
Facilities
Internal
Fourth
1975-1982
1000 above
VLSIC
Introduction of Non-procedural language
Flexible internal & external storage
Fifth
1982 and above
106chips
AI and Expert
system
Introduction of object oriented programming language
Small but powerful network
GENERAL EVALUATION
Differentiate between the first and second generation of computers.
Which of the generation of computer uses microchips?
Which of the generation of computers used VLSIC?
What is non-procedural programming?
READING ASSIGNMENT
Any recommended text.
WEEKEND ASSIGNMENT
AI means………….A. artefact intelligence B. artificial intellect C. artificial intelligence D. attitude intelligence.
Which of the generation of computer was between 1975 and 1982? A. First B. Second C. Fifth D. Fourth
Which of the generation of computer used vacuum tube? A. First B. Second C. Fifth D. Fourth
Which of the generation of computers used VLSIC? A. First B. Second C. Fifth D. Fourth
Which of the generation of computers begins Non Procedural programming? A. First B. Second C. Fifth D. Fourth
THEORY
What is artificial intelligence?
Explain second generation of computers.
WEEK FIVE
TOPIC: CLASSIFICATION OF COMPUTER BY TYPES
Computers can be classified by types into THREE major types. They are:
DIGITAL COMPUTER
ANALOGUE COMPUTER
HYBRID COMPUTER
DIGITAL COMPUTER
This is the most common type of computer today. It measures physical quantities by counting. Examples are calculator,digital wrist watches, digital fuel dispenser etc.
ANALOGUE COMPUTER
This type of computer is used to measure and process continuous data such as speed, temperature, heartbeat etc. Examples are speedometer, thermometer etc.
HYBRID COMPUTER
This type of computer combines the features of digital and analogue computers together. It is a combinations of digital and analogue computers.
EVALUATION
List the classification of computers according to type
Explain the difference between the classifications of computer according to type.
CLASSIFICATION OF COMPUTER BY FUNCTIONALITY
Classification of computer according to purpose can be grouped into two (2), namely:
General purpose computers
Special purpose computers
SPECIAL PURPOSE COMPUTERS
These are computers designed solely to solve a restricted class of problem e.g computer for medical diagnosis, weapon guidance, traffic control, weather study and forecast etc.
GENERAL PURPOSE COMPUTERS
These are computers designed solely to solve a vast variety of problems e.g it can be used for Word processing and at the same time used for graphics, database, spreadsheet etc.
GENERAL EVALUATION
What is the difference between general purpose computers and special purpose computers?
Explain the following: digital, analogue and hybrid computers.
Give any two examples of general purpose computer.
Mention classification of computer by purpose.
READING ASSIGNMENT
Hiit Data Processing For Senior Secondary Education, Pg 13
WEEKEND ASSIGNMENT
How many classifications of computers do we have? A. 2 B. 4 C. 7 D. 3
The generation of computerthat uses AI is A. third B. second C. fifth D. first
……..is the smallest and the most popular class of computers. A. Micro B. Mini C. Super D. Mainframe.
What type of computercombines both features of digital and Analogue computers? A. micro B. hybrid C. digital D. super
Computers designed solely to solve a restricted class of problem is called A. general purpose B. special purpose C. digital D. analogue
THEORY
List the classifications of computers according to type.
Explain the difference between the classifications of computers according to type.
WEEK SIX
TOPIC: CLASSIFICATION OF COMPUTERS BY SIZE
Computers can be generally categorized into four, namely:
Super computers
Mainframe computers
Mini computers
Micro computers
SUPER COMPUTER
These are the largest, fastest and most expensive computers. The cost is several millions of dollars and the speed is between 600 million to 900 million instructions per second (MIP).
Another name for super computer is MONSTER. Scientists in weather forecasting, exploration make use of super computers. It can also be used for complex calculations e.g CRAY, X-MP etc.
MAINFRAME COMPUTERS
A mainframe computer is a large computer in terms of price, size of internal memory and speed. It has a variety of peripheral devices such as printers, plotters etc more than those found with small computers, except small computers with large amount of external storage.
Mainframe computers usually need a specialized environment to operate, with dust, temperature and humidity carefully controlled. They are used in large establishments e.g banks, airports etc. Examples of Mainframe computers are IBM 360/370,NCR-V 8800.
CONCLUSION
We learnt that computers are categorized into four which are: super computer, mainframe computer, minicomputer and microcomputer
EVALUATION
What is another name for super computer?
Mention TWO examples of mainframe computer.
MINI COMPUTERS
Mini computers were developed in the 1970s for specialized tasks (i.e they are special purpose computers). They are smaller and less powerful and less expensive than mainframes.
Mini computers, as they are called, are easier to install and operate e.g PDP II, VAX 750/6000, NCR 9300, DEC, HP 3000 etc.
MICRO COMPUTERS
A microcomputer is a computer whose central processing unit (CPU) is based on a microprocessor.
Micro computers are at present the most popular of computers. They are very small. The capability is generally not as many and not as complex as mini computers or Mainframe computers. They are easy to use. Another name for microcomputer is Personal Computer (PC).
REASONS WHY MICRO COMPUTERS ARE WIDELY USED
They are cheap.
They have small sizes.
They do not require special environment for their operations.
They can be used anywhere.
CONCLUSION
Microcomputers are the most popular and most widely used among the categories of computers. Another name for a microcomputer is Personal Computer (PC).
GENERAL EVALUATION
Mention four classifications of computers by size.
Differentiate between mini and microcomputers.
Give two examples of minicomputer.
Mainframe computers are used for …….
READING ASSIGNMENT
HiiT @ Schools for Senior Secondary Education Data Processing, pg14-15
WEEKEND ASSIGNMENT
The most popularly used categories of computers is ……
A. microcomputer B. minicomputer C. super computer
Another name for microcomputer is……
A. home computer B.personal computer C. analogue computer.
HP 3000 is an example of……..computers. A. super B. mainframe C. mini.
Mini computers were developed in the …….A. 1970s B. 1980s C. 1990s.
Mainframe computers can be used in the …..A. bank B. church C. market D. none
THEORY
a) List any two examples of mini computers.
b) What is another name for microcomputers?
2. List any two reasons why micro computers are widely used.
WEEK SEVEN
TOPIC: DIGITALIZATION OF DATAI
Digitalization is the process of converting information into digital format. This information may represent an object, image, sound, document or a signal (usually an analog signal) organized into discrete set of its points or samples. This is the binary data that computers and many devices with computing capacity (such as digital camera and digital hearing aids) can process.
Digitalization can also be defined as the integration of digital technologies into everyday life. Digital system uses a binary numeric system in which electronic pulses are represented by either 0 for a Low pulse or 1 for a High pulse. Digital can more easily represent symbols such as alphanumeric characters that represent real world data than the analog system.
BENEFITS OF DIGITALIZATION
Long term preservation of documents
Orderly archiving of documents
Easy and customized access to information
Easy information dissemination through images and text, CD-ROM, Internet, Intranet and extranets.
TYPES OF DIGITAL COMPUTER
Micro computers
Mini computers
Mainframe computers
Super computers
TECHNOLOGY OF DIFFERENT INFORMATION AGE
The ages are:
Stone age
Iron age
Middle age
Industrial age
Electronic age
Information age
Tools used
Purpose
Time period
Examples of tools in that age
Stone age
Stone
Sewing, cutting, counting, defence, transaction, storage, pottery exhibitions.
Below 12th century
Basalt, sandstone flint etc.
Iron age
Iron
Defence, Agric
12thcentury
Hoes and cutlass
Middle age
Writing materials
Knowledge transfer, education
12th and 13th century
Pen feather etc
Industrial age
Coals
Power development, faster movement
Late 18th and early 19th century
Cars, Ships etc
Electronic age
Computer
Storage, accuracy, soeed.
Timeliness
Late 19th century and above
Circuit, Processor.
EVALUATION
State the different information ages.
State the tools used in each age.
EARLY COUNTING DEVICES
Fingers and Toes
Stone
Sticks
Pebbles
Cowries
In the early days of man’s existence on earth, counting and simple arithmetic were performed using different parts of the body and some other counting aids. The following are devices used by people of ancient times.
FINGERS AND TOES
In ancient times, calculations were done by the use of fingers and toes. Fingers were usedfor simple addition and toes were used together with fingers in order to count up to twenty. The following problems were faced using fingers and toes to count:
They could not be used conveniently to count numbers more than twenty.
The result obtained from counting with fingers could not be easily remembered.
STONES AND PEBBLES
Stones were introduced for counting because of the limitations of counting with fingers and toes. Counting with stones involves building a pile of stones where each represents a quantity. The following were problems faced using stones as counting devices:
Large numbers of stones were too heavy to carry from one place to other.
It was cumbersome to count if the counting process involved large numbers.
GRAINS
The use of grains was introduced because of the heaviness of stones. Grains can be kernel, beans, rice, corn etc. Grains were used the same way as stones.
STICKS
These are small pieces of wood that are used for counting in place of stones and grains. Children in nursery and primary schools use match sticks for counting.
MARKS ON THE WALL
This involves the use of sharp objects in drawing line on the wall for the purpose of counting.
Continuous marks on walls will make a wall dirty.
DISADVANTAGES OF EARLY COUNTING DEVICES
They are difficult to carry about.
Counting and calculation takes a lot of time.
They are prone to mistakes.
They cannot be used to count or calculate large numbers.
Their results cannot be easily remembered.
They have no storage facilities.
GENERAL EVALUATION
Mention types of computer according to sizes.
Which of the size is used for weather forecast?
Another name for mainframe computer is ……
List any two examples of mini computers.
Mention the four categories of computers.
READING ASSIGNMENT
A Handbook on computer studies for schools, pgs 1-3, by NiyiAdekolegan.
WEEKEND ASSIGNMENT
The ancient man began counting by using ……A. fingers B. slide rule C. abacus D. none
The following are examples of early counting methods except ……A. calculator B. pebbles C. grains D. none
In using fingers and toes, you can only count up to …….A. 20 B. 40 C. 50 D. 100
The following can be used for counting in the ancient times except…..A. fingers B. computer C. stones D. none
The stages of development of the computer machine are known as……..A. computer age B. computer history C. computer generation D. all
THEORY
Mention any THREE early counting devices.
List any TWO disadvantages of early counting devices.
WEEK EIGHT
TOPIC: DIGITALIZATION OF DATA II.
COMPONENTS OF A COMPUTER SYSTEM
A computer system consists of three main parts otherwise called components. They are :
Hardware
Software
People ware
HARDWARE COMPONENT
The computer hardware could be defined as the physical parts of the computer that we see, feel and handle. It consists of device for input, processing, storage, output and communications.
Hardware can be divided into two sections:
System Unit
The peripherals
HARDWARE
Hardware is the physical parts of the computer system that you can see and touch. They are the components that make up the visible computer. It consists of devices for input, processing, storage, output and communications.
The basic parts of computer hardware can be divided into:
System Unit
Peripherals
CPU/SYSTEM UNIT
The CPU is the brain of computer system and it can subdivided into:
Control Unit
Arithmetic and Logic Unit
Memory Unit
CONTROL UNIT
This is the unit of the computer system that fetches instructions from the main storage, interpret them and issue all the necessary signals to the components making up the system.
ARITHMETIC AND LOGIC UNIT
This part of the CPU is where all arithmetic operations are carried out in the computer. This unit is also involved in decision making. Logic functions such as less than (<), equal (=), greater than (>) etc which are operations of comparisons are used for decision making.
MEMORY UNIT
The memory or primary storage unit is the place in the computer where the program and the data are stored. The computer memory is divided into two namely:
Random Access Memory (RAM)
Read Only Memory (ROM)
PERIPHERALS
The peripherals are devices outside the CPU but function under the control of the CPU e.g mouse, keyboard, printer etc.
EVALUATION
What are the components of the computer system?
What are the classes of hardware?
SOFTWARE
Software is the set of instructions that is used to direct the computer hardware to perform its tasks. That is, it is a set of instructions that makes the users to do work and allow the computer to operate. Software is basically programs i.e another name for software is program.Program is the sequence of instructions given to computer to solve a given problems or accomplish a given task. There are two main classes of software which are:
System software
Application software
SYSTEM SOFTWARE
These are programs written by the manufacturer to control the smooth running of the computer.
APPLICATION SOFTWARE
These are programs written by programmers to instruct the computer to perform a particular task.
EVALUATION
What is software?
What is the difference between system and application software?
PEOPLE WARE
These are people who make and use the computer. They range from professional users to operational users. A user could also be anyone who makes use of computer. Without people, the computer cannot work. There two main classes of people ware:
Computer professionals.
Computer users.
EVALUATION
Can the computer system work without people?
Software is subdivided into………...and ………
What are the three components of the system unit?
Explain the function of each component of the CPU.
PERIPHERALS
Peripherals are in three categories:
Input Devices
Output Devices
Auxiliary Storage Devices
EVALUATION
What is the difference between input and output device?
Give four examples of auxiliary device.
MICRO COMPUTER
Sizes of Microcomputer are:laptop, palmtop, handtop, desktop, tower etc.
PARTS OF MICROCOMPUTER
SYSTEM UNIT
MONITOR (VDU)
KEYBOARD
MOUSE
THE MICROCOMPUTER
A computer is an electronic machine which accepts data as input, processes the data and gives out information under the control of stored programs. The information which the computergives out is called OUTPUT.
There are three keywords to note in the definition:
COMPUTER AS A MACHINE
This is the physical aspect of a computer known as computer hardware. It consists of electronic and electro-mechanical parts working together to process data.
COMPUTER PROCESSES DATA
It accepts data (input).
It processes data (processing).
It supplies information (output).
A COMPUTER IS CONTROLLED BY A STORED PROGRAM
A program is a set of instructions which tells the computer to perform a given task. A computer does not understand English or any of the Nigerian languages. Rather it has its own language called PROGRAM.
MAIN PARTS OF A MICRO COMPUTER
The microcomputer is divided into three main parts namely:
Central Processing Unit (CPU)
Monitor
Keyboard
CONCLUSION
We have learnt the definition of a computer, that is, computer is an electronic machine which accepts data as input, processes the data and gives out information under the control of stored programs. We also learnt that the computer is divided into three main parts which are Central Processing Unit, Monitor and Keyboard.
GENERAL EVALUATION
Mention the three main parts of microcomputer.
List the four types of computers according to size.
What is microcomputer?
State the difference between CPU and system unit.
READING ASSIGNMENT
Hiit @ Schools For Senior Secondary Education, Data Processing, By HiitPlc, Pgs 13-15
WEEKEND ASSIGNMENT
……..is an electronic machine which accepts data as input, processes data and gives out information. A. Television B. Computer C. Photocopier D. None
A computer accepts data as……..A. input B. output C. processing D. store
The microcomputer is divided into ……..parts. A. 3 B. 4 C. 5 D. 9
The information which the computer gives is called …….. A. input B. output C. processing D. None
The language the computer understands is called…….. A. English B. programs C. French D. all languages
THEORY
What is a program?
Mention the main parts of a computer.
WEEK NINE
TOPIC: ICT APPLICATION IN EVERYDAY LIFE
INTRODUCTION
ICT has turned this world to a global village. Apart from communication, that is, reaching people both far and near; it has also made the work easier and better.
Better productivity, salaries, health care and even farming and education.
SECTORS WHERE ICT HAS PLAYED MAJOR ROLE
Education
Banking
Industry
Commerce
EDUCATION
ICT is applied in the education sector in the following ways:
Research for teaching materials, online conference etc.
ICT or computers are used as a reference tools.
ICT or computer is used by the researchers to collect and process data.
Computers are used as administrative tools.
ICT offers interactive learning.
BANKING SECTOR
Banks use computers to control the entire banking system.
On-line transactions by customers are possible 24 hour.
Accessing company account by businessmen On-line.
Supervision of banking activities by bank administrators.
INDUSTRY
Computers are used to facilitate production planning and control system.
Automation in the production of goods.
Researchers use computers to analyse and collect data for future reference.
Computers are used by administrators to oversee the entire operations in the factory.
COMMERCE
ICT makes buying and selling easier.
Computers are used by customers to connect On-line with Suppliers.
Computers are used to keep record of transaction.
ICT is applied as a means of communication between customers and the producers.
IMPACT OF ICT ON THE SOCIETY
Faster communication speed.
Lower communication cost.
Reliable mode of communication.
Effective sharing of information.
Borderless communication.
NEGATIVE EFFECTS OF ICT
Insecurity of data
Fraud
Unemployment
Virus threat
Cost of setting up ICT gadgets
EVALUATION
Define the term ICT.
Mention some ICT gadgets.
GENERAL EVALUATION
Explain the relevance of ICT in the music industry.
What do you understand by saying “ICT has turned the whole world to a Global village”?
List any five negative side of ICT.
Mention areas where ICT has played key role.
READING ASSIGNMENT
HiiT@ schools Data Processing for Senior Secondary Education, pgs 16-18.
WEEKEND ASSIGNMENT
The following are disadvantages of ICT except A. fraud B. virus C. faster communication D. none
ICT has turned the whole world into a ……A. global village B. galaxy C. universe D. none
The production of goods with or without human intervention using computer is known as …….A. automation B. AI C. expert system D. vacuum tube
E-commerce stands for ……..A. electric commerce B. electronic commerce C. electrical commerce. D. none
ATM means ……. A. Automatic Teller Machine B. Automated Teller Machine C. Auto Teller Machine D. None
THEORY
State three uses of ICT.
List three ways ICT has assisted in the social development.
WEEK TEN
TOPIC: DATA AND INFORMATION
DEFINITION OF DATA
Data are raw, unorganized or unprocessed facts that need to be processed. Data can be something simple and seemingly random and useless until it is organised.
TYPES OF DATA
Qualitative data i.e descriptive information
Quantitative data i.e numeric information
SUBDIVISION OF QUANTITATIVE DATA
Continuous data: this can take any value. It is also known as measured data. It can take value within a range e.g 0-99, 10-20 etc.
Discrete data: this type of data is whole in nature. It is not continuous. It takes a whole numbers and also called Counted data.
FORMS OF DATA
Numeric i. e 0-9
Letters i.e a-z or A-Z
Symbols e.g + , _ , * , % , = , <, >, etc
EXAMPLES OF DATA
Numbers, name of thing, place or animal, words, measurements, observations, descriptions of things etc.
SOURCES OF DATA
Data can come from different sources depending on the importance of the data. The following are sources of data: television, internet, articles, government documents and public records, newspaper, textbooks, biographies.
EVALUATION
Define data.
Explain the two types of data.
Mention any five sources of data.
INFORMATION
This refers to data that have been converted into a more meaningful and useful form.
It refers to a processed data that is meaningful to the user.
EXAMPLES OF INFORMATION
Student ID card
Weather reports
Student’s report card
International passport
Utility bills e.g PHCN bills, Water bills
SOURCES OF INFORMATION
Internet, Database, Magazine/ Newspaper, Census board, Documents, Observation etc
CHARACTERISTICS OF GOOD INFORMATION
Relevance: it must be relevant and good enough for its purpose.
Reliability: it must come from a reliable source.
Accuracy: it must be an end product of processed data. That is, it must be error-free.
Availability: it must be available and communicated to the user as at when it is needed.
Suitability: it must be expressed in the form the user of the information can understand it and of suitable for its purpose.
DATA HANDLING
This the process of ensuring that research data is stored, archived or disposed off in a safe and secure manner during and after the conclusion of a research project.
WAYS OF HANDLING DATA
Electronic methods: Data can be handled electronically ensures data integrity. It includes personal digital assistants (PDA), storage media, CD/DVD, MEMORY CARDS etc.
Non-Electronic methods: This method includes paper files, journals and laboratory notebooks. It is basically called manual method in which human energy and effort are used to process data.
GENERAL EVALUATION
Mention any five sources of information.
Differentiate between data and information.
State any three forms of data.
Mention the two types of data
What is the difference between continuous data and discrete data?
READING ASSIGNMENT
Hiit @ schools data processing for Senior Secondary Education, pgs 8-9
WEEKEND ASSIGNMENT
……..are raw facts which have not undergone processing.
A. Information B. Data C. Record D. None
One of the characteristics of good information has to do with the correctness of information. A. reliability B. availability C. accuracy D. none
……..refers to the information that has been processed.
A. Data B. Information C. Database D. None
There are ……… types of data. A. 2 B. 3 C. 4 D. 8
The process of surfing the NET to get information for further research is …….
A. primary source B. on-line C. secondary source D. None
THEORY
Mention and explain the two ways of handling data.
Explain at least four characteristics of good information.
SS2
Data processing
WEEK 2 TOPIC: information processing
CONTENT
Information processing
Information processing is the acquisition, recording, organization, retrieval, display and dissemination of information.
Information processing could also be referred to as the manipulation of digitalized information by computers and other digital electronic equipment, known collectively as Information technology.
A computer information processor processes information to produce understandable results. For example, an information processor works to translate and format the digital information for printed form.
Collation of Information
Collation is the assembly of written information into a standard order. Many systems of collation are based on numerical order or alphabetical order, or extensions and combinations thereof. Collation is a fundamental element of most office filing systems, library catalogs, and reference books.
The main advantage of collation is that it makes it fast and easy for a user to find an element in the list, or to confirm that it is absent from the list. In automatic systems this can be done using a binary search algorithm or interpolation search; manual searching may be performed using a roughly similar procedure, though this will often be done unconsciously. Other advantages are that one can easily find the first or last elements on the list (most likely to be useful in the case of numerically sorted data), or elements in a given range (useful again in the case of numerical data, and also with alphabetically ordered data when one may be sure of only the first few letters of the sought item or items).
Information organization
Information organization (IO) is defined in this literature review as the process of ordering, surrogation, or description information and information objects. These three tasks have been identified by the author as broad tasks that both identify tangible elements of IO and have implications across areas of information research including retrieval, interaction, and personal information management.
Analysis of Information
Information analysis is the science of evaluating information content, and refining information to build portfolios. Information analysis works both for managers who use a non-quantitative process and for those who use a quantitative investment process. The only requirement is that there is a process./
Information is a fuzzy concept. Information analysis begins by transforming information into something concrete: investment portfolios. Then it analyzes the performance of those portfolios to determine the value of the information.
Information analysis can work with something as simple as an analyst’s buy and sell recommendations. Or it can work with alpha forecasts for a broad universe of stocks. Information analysis is not concerned with the intuition or process used to generate stock recommendation only with the recommendations themselves.
Information Interpretation
Information interpretation is the process through which organizations make sense of new information that they have acquired and disseminated.
Items
Our employees, as individuals, are prepared to rethink decisions when presented with new and relevant information. (0.65)
Our employees seek to deeply understand issues and concepts. (0.46)
Our employees do not hesitate to question things they do not understand. (0.65)
Our employees, as individuals, are interested in knowing not only what to do but also why we do things. (0.78)
WEEK 3-4
TOPIC: Process of information transmission
CONTENT
Chart
A chart, also called a graph, is a graphical representation of data, in which "the data is represented by symbols, such as bars in a bar chart, lines in a line chart, or slices in a pie chart".[1] A chart can represent tabular numeric data, functions or some kinds of qualitative structure and provides different info.
The term "chart" as a graphical representation of data has multiple meanings:
A data chart is a type of diagram or graph, that organizes and represents a set of numerical or qualitative data.
Maps that are adorned with extra information (map surround) for a specific purpose are often known as charts, such as a nautical chart or aeronautical chart, typically spread over several map sheets.
Other domain specific constructs are sometimes called charts, such as the chord chart in music notation or a record chart for album popularity.
Charts are often used to ease understanding of large quantities of data and the relationships between parts of the data. Charts can usually be read more quickly than the raw data that they are produced from. They are used in a wide variety of fields, and can be created by hand (often on graph paper) or by computer using a charting application. Certain types of charts are more useful for presenting a given data set than others. For example, data that presents percentages in different groups (such as "satisfied, not satisfied, unsure") are often displayed in a pie chart, but may be more easily understood when presented in a horizontal bar chart.[2] On the other hand, data that represents numbers that change over a period of time (such as "annual revenue from 1990 to 2000") might be best shown as a line chart.
Mobile Phone
Definition - What does Mobile Phone mean?
A mobile phone is a wireless handheld device that allows users to make calls and send text messages, among other features. The earliest generation of mobile phones could only make and receive calls. Today’s mobile phones, however, are packed with many additional features, such as Web browsers, games, cameras, video players and even navigational systems.
A mobile phone may also be known as a cellular phone or simply cellphone.
Mobile Phone
When the first mobile phones were introduced, their only function was to make calls, and they were so bulky it was impossible to carry them in a pocket.
Later, mobile phones belonging to the Global System for Mobile Communications (GSM) network were capable of sending and receiving text messages. As these devices evolved, they became smaller and more features were added, such as multimedia messaging service (MMS), which allowed users to send and receive images.
Most of these MMS-capable devices were naturally equipped with cameras, which allowed users to capture photos with the built-in camera, add captions, and send them to friends and relatives who also had MMS-capable phones.
A mobile phone with highly advanced features is called a smartphone, while a regular mobile phone is known as a feature phone.
A mobile phone typically operates on a cellular network, which is composed of cell sites scattered throughout cities, countrysides, and even mountainous regions. If a user happens to be located in an area where there is no signal from any cell site belonging to the cellular network provider he or she is subscribed to, calls cannot be placed or received in that location.
NEWSPAPER
a publication issued at regular and usually close intervals, especially daily or weekly, and commonly containing news, comment, features, and advertising.
Radio
The Alexandra Palace, here: mast of the broadcasting station
Classic radio receiver dial
Radio is the radiation (wireless transmission) of electromagnetic energy through space.[n 1] The biggest use of radio waves is to carry information, such as sound, by systematically changing (modulating) some property of the radiated waves, such as their amplitude, frequency, phase, or pulse width. When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form.
Radio systems need a transmitter to modulate (change) some property of the energy produced to impress a signal on it, for example using amplitude modulation or angle modulation (which can be frequency modulation or phase modulation). Radio systems also need an antenna to convert electric currents into radio waves, and vice versa. An antenna can be used for both transmitting and receiving. The electrical resonance of tuned circuits in radios allow individual stations to be selected. The electromagnetic wave is intercepted by a tuned receiving antenna. A radio receiver receives its input from an antenna and converts it into a form usable for the consumer, such as sound, pictures, digital data, measurement values, navigational positions, etc.[2] Radio frequencies occupy the range from a 3 kHz to 300 GHz, although commercially important uses of radio use only a small part of this spectrum.[3]
A radio communication system sends signals by radio.[4] The radio equipment involved in communication systems includes a transmitter and a receiver, each having an antenna and appropriate terminal equipment such as a microphone at the transmitter and a loudspeaker at the receiver in the case of a voice-communication system.[5]
Telephone
A rotary dial telephone, c.1940s
Modern telephones use push buttons
A telephone, or phone, is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals suitable for transmission via cables or other transmission media over long distances, and replays such signals simultaneously in audible form to its user.
In 1876, Scottish emigrant Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice. This instrument was further developed by many others. The telephone was the first device in history that enabled people to talk directly with each other across large distances. Telephones rapidly became indispensable to businesses, government, and households, and are today some of the most widely used small appliances.
The essential elements of a telephone are a microphone (transmitter) to speak into and an earphone (receiver) which reproduces the voice in a distant location. In addition, most telephones contain a ringer which produces a sound to announce an incoming telephone call, and a dial or keypad used to enter a telephone number when initiating a call to another telephone. Until approximately the 1970s most telephones used a rotary dial, which was superseded by the modern DTMF push-button dial, first introduced to the public by AT&T in 1963.[1] The receiver and transmitter are usually built into a handset which is held up to the ear and mouth during conversation. The dial may be located either on the handset, or on a base unit to which the handset is connected. The transmitter converts the sound waves to electrical signals which are sent through the telephone network to the receiving phone. The receiving telephone converts the signals into audible sound in the receiver, or sometimes a loudspeaker. Telephones permit duplex communication, meaning they allow the people on both ends to talk simultaneously.
Television
Flat-screen televisions for sale at a consumer electronics store
A television, commonly referred to as TV, telly or the tube, is a telecommunication medium used for transmitting sound with moving images in monochrome (black-and-white), or in colour, and in two or three dimensions. It can refer to a television set, a television program, or the medium of television transmission. Television is a mass medium, for entertainment, education, news and advertising.
Television signals were initially distributed only as terrestrial television using high-powered radio-frequency transmitters to broadcast the signal to individual television receivers. Alternatively television signals are distributed by co-axial cable or optical fibre, satellite systems and via the Internet.
Types of information transmission
Wireless
A handheld On-board communication station of the maritime mobile service
Wireless communication is the transfer of information between two or more points that are not connected by an electrical conductor.
The most common wireless technologies use radio. With radio waves distances can be short, such as a few meters for television or as far as thousands or even millions of kilometers for deep-space radio communications. It encompasses various types of fixed, mobile, and portable applications, including two-way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other examples of applications of radio wireless technology include GPS units, garage door openers, wireless computer mice, keyboards and headsets, headphones, radio receivers, satellite television, broadcast television and cordless telephones.
Somewhat less common methods of achieving wireless communications include the use of other electromagnetic wireless technologies, such as light, magnetic, or electric fields or the use of sound.
Communications satellite
An Advanced Extremely High Frequency communications satellite relays secure communications for the United States and other allied countries.
A communications satellite is an artificial satellite that relays and amplifies radio telecommunications signals via a transponder; it creates a communication channel between a source transmitter and a receiver(s) at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. There are over 2,000 communications satellites in Earth’s orbit, used by both private and government organizations.[1]
Wireless communication uses electromagnetic waves to carry signals. These waves require line-of-sight, and are thus obstructed by the curvature of the Earth. The purpose of communications satellites is to relay the signal around the curve of the Earth allowing communication between widely separated points.[2] The electromagnetic signals that communication satellites work with, have a large spectrum of wavelengths and frequencies.
CABLE
Cable communicaTION rerfer to the transmission of data over a wired-based communication technilogy . Examples include telepoine network,cable television or internet accesss and fibre – optic communication.
RECEIVER
The receiver in information theory is the receiving end of a communication channel. It receives messages / information from a sender, who first encoded them. Sometimes the receiver is modeled so as to include the decoder.
WEEK 5
TOPIC: Means of transmitting information
CONTENT
MEANS OF TRANSMITTING INFORMATION
Electronic transmission
"Electronic transmission" means any process of communication that does not directly involve the physical transfer of paper and that is suitable for the retention, retrieval and reproduction of information by the recipient.it is also referred to as the use of electronic media for transmitting information e.g. Radio waves
Non electronic transmission
Information has been sent via non-electronic means since the advent of communication eg. Optical, acoustic, and mechanical.
These include newspaper, and charts
WEEK 6
TOPIC: Computer Ethics
CONTENT
Computer Lab Rules and Ethics – Concept Outline
I. You will do much in the labs during your years at Challenger. In order that that those years be productive
You will learn the rules of conduct expected for the lab.
You will know what the consequences of misbehavior are.
You will learn about the ethics of software usage.
You will learn to use the Internet safely.
II. Put all books and personal items on the shelves by the door when you come in the lab.
There’s not enough room at the computers for any personal material except your paper and pencil.
III. You must be working on your project at all times. You are not allowed to be in here to “play” on the computers, there is work to be done.
Students may not
Change the desktop in any way.
Change the screensaver.
Delete, move, or rename any files.
Install any software downloaded from the Internet or any other source.
Open personal e-mail accounts.
Install or open chat programs such as Instant Messenger.
Use computer games such as Solitaire, Minesweeper, etc. without permission from the teacher.
While it is possible to have fun, if you are caught not working on the the assignment, it will be considered computer misuse.
IV. There is no food, drink, or candy allowed in the lab please enter the lab with clean hands.
Treat the computer with respect:
Hands off the monitor
Gentle use of the keyboard and mouse (Leave it on the pad, please)
Take care when handling media.
V. Use good posture while sitting at the computer (eyes level with the monitor, shoulders down, arms relaxed, feet flat on the floor, back supported).
VI. Obey all regular classroom rules. Policies & Procedures of your regular classroom teacher are in effect here just like the classroom. Do your own work; don’t disturb your neighbors.
VII. What happens when the rules are broken?
1st offense:
Student is removed from computer for the remainder of class period and will write an explanation of misconduct or misuse. Student will be responsible for repair or replacement.
2nd offense:
Student is sent to In-House Suspension for remainder of class period. It is up to the classroom teacher’s discretion if the student can make up missed work. Student will be responsible for repair or replacement.
3rd offense:
Student has no more computer lab privileges. Student will be responsible for repair or replacement.
VIII. Etiquette means manners: be polite, have respect for other’s property just like they should have for yours. Be honest--do your own work.
IX. Copyright Laws
Fair use clause for education.
Difference between classroom use and published work.
Copying software.
Citing electronic sources.
X. Hacking: unauthorized use of school computer hardware or software.
Huntsville City Schools Discipline Policy –
Class 2 Offense: without causing damage
Class 3 Offense: causing damage
XI. Internet Safety
Never reveal personal information (name, address, age, phone number)
Never give anyone your Social Security number, credit card numbers, your parents’ name(s)
Never arrange to meet someone face-to-face you have met on-line
Don’t share photos of yourself with someone you only know on-line
Don’t share passwords with anyone except your parents and teachers
WEEK 7
TOPIC: Computer safety measures
CONTENT
Computer Safety Measures
• Anti-virus software is your computer's best defense against malware (e.g., viruses, Trojan horses, worms, spyware) – install and update anti-virus software on your computer and regularly scan your computer to make sure it is free from malware
• Download the latest system and application updates for your computer, which may include important security patches
• Make sure that the security tools on your computer are up to date, and select the automatic update option if possible
• Do not access the Internet without first enabling an updated firewall, especially when using DSL or a cable modem
• If your security software has identified malware on your computer, you need to remove it and then change your Online Banking password
• Avoid clicking attachments or links in unsolicited email messages, doing so could lead to the0020installation of malware on to your computer
• For your security, always type the Internet address (e.g., www.key.com) directly into your browser
• Always sign out and close your browser after using a secure website
• When your computer is not in use, consider shutting it down or disconnecting it from the Internet
WEEK 8
TOPIC: Operating System
CONTENT
Operating system
Operating systems
Common features
Process management
Interrupts
Memory management
File system
Device drivers
Networking
Security
I / O
An operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. The operating system is a component of the system software in a computer system. Application programs usually require an operating system to function.
Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources.
For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware,[1][2] although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer—from cellular phones and video game consoles to web servers and supercomputers.
Examples of modern operating systems include Apple OS X, Linux and its variants, and Microsoft Windows.
Types of operating systems
Single- and multi-tasking
A single-tasking system can only run one program at a time, while a multi-tasking operating system allows more than one program to be running in concurrency. This is achieved by time-sharing, dividing the available processor time between multiple processes which are each interrupted repeatedly in time-slices by a task scheduling subsystem of the operating system. Multi-tasking may be characterized in preemptive and co-operative types. In preemptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, e.g., Solaris, Linux, as well as AmigaOS support preemptive multitasking. Cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking. 32-bit versions of both Windows NT and Win9x, used preemptive multi-tasking.
Single- and multi-user
Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem.[3] A multi-user operating system extends the basic concept of multi-tasking with facilities that identify processes and resources, such as disk space, belonging to multiple users, and the system permits multiple users to interact with the system at the same time. Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources to multiple users.
Distributed
A distributed operating system manages a group of distinct computers and makes them appear to be a single computer. The development of networked computers that could be linked and communicate with each other gave rise to distributed computing. Distributed computations are carried out on more than one machine. When computers in a group work in cooperation, they form a distributed system.[4]
Templated
In an OS, distributed and cloud computing context, templating refers to creating a single virtual machine image as a guest operating system, then saving it as a tool for multiple running virtual machines. The technique is used both in virtualization and cloud computing management, and is common in large server warehouses.[5]
Embedded
Embedded operating systems are designed to be used in embedded computer systems. They are designed to operate on small machines like PDAs with less autonomy. They are able to operate with a limited number of resources. They are very compact and extremely efficient by design. Windows CE and Minix 3 are some examples of embedded operating systems.
Real-time
A real-time operating system is an operating system that guarantees to process events or data within a certain short amount of time. A real-time operating system may be single- or multi-tasking, but when multitasking, it uses specialized scheduling algorithms so that a deterministic nature of behavior is achieved. An event-driven system switches between tasks based on their priorities or external events while time-sharing operating systems switch tasks based on clock interrupts.[citation needed]
Library
A library operating system is one in which the services that a typical operating system provides, such as networking, are provided in the form of libraries. These libraries are composed with the application and configuration code to construct unikernels — which are specialised, single address space, machine images that can be deployed to cloud or embedded environments.
WEEK 9
TOPIC: Examples of Operating System
CONTENT
Definition: An operating system is a collection of programs that control the application software that users run and provides a link between the hardware and software currently running on the computer. The operating system is also responsible for the management and control of all resources (memory, hard drives, monitor, etc.) that are shared amongst the different application programs that may be running simultaneously.
Examples of common personal computer operating systems:
Windows 7
Windows Vista
Windows Server 2003
Linux
Mac OS X
SunOS
Alternate Spellings: OS, O/S, kernel
Examples: Google announced that they are developing a new operating system that users will be able to use to run on their PCs.
WEEK 10
TOPIC: Functions of Operating System
CONTENT
Basic functions of an operating system
Definition
An operating system is a group of computer programs that coordinates all the activities among computer hardware devices. It is the first program loaded into the computer by a boot program and remains in memory at all times.
Functions of an operating system
The basic functions of an operating system are:
Booting the computer
Performs basic computer tasks eg managing the various peripheral devices eg mouse, keyboard
Provides a user interface, e.g. command line, graphical user interface (GUI)
Handles system resources such as computer's memory and sharing of the central processing unit (CPU) time by various applications or peripheral devices
Provides file management which refers to the way that the operating system manipulates, stores, retrieves and saves data.
Booting the computer
The process of starting or restarting the computer is known as booting. A cold boot is when you turn on a computer that has been turned off completely. A warm boot is the process of using the operating system to restart the computer.
Performs basic computer tasks
The operating system performs basic computer tasks, such as managing the various peripheral devices such as the mouse, keyboard and printers. For example, most operating systems now are plug and play which means a device such as a printer will automatically be detected and configured without any user intervention.
Provides a user interface
A user interacts with software through the user interface. The two main types of user interfaces are: command line and a graphical user interface (GUI). With a command line interface, the user interacts with the operating system by typing commands to perform specific tasks. An example of a command line interface is DOS (disk operating system). With a graphical user interface, the user interacts with the operating system by using a mouse to access windows, icons, and menus. An example of a graphical user interface is Windows Vista or Windows 7.
The operating system is responsible for providing a consistent application program interface (API) which is important as it allows a software developer to write an application on one computer and know that it will run on another computer of the same type even if the amount of memory or amount of storage is different on the two machines.
Handles system resources
The operating system also handles system resources such as the computer's memory and sharing of the central processing unit (CPU) time by various applications or peripheral devices. Programs and input methods are constantly competing for the attention of the CPU and demand memory, storage and input/output bandwidth. The operating system ensures that each application gets the necessary resources it needs in order to maximise the functionality of the overall system.
Provides file management
The operating system also handles the organisation and tracking of files and directories (folders) saved or retrieved from a computer disk. The file management system allows the user to perform such tasks as creating files and directories, renaming files, coping and moving files, and deleting files. The operating system keeps track of where files are located on the hard drive through the type of file system. The type two main types of file system are File Allocation table (FAT) or New Technology File system (NTFS).
Types of file system
File Allocation table (FAT)
New Technology file system (NTFS)
File Allocation table (FAT) uses the file allocation table which records, which clusters are used and unused and where files are located within the clusters.
NTFS is a file system introduced by Microsoft and it has a number of advantages over the previous file system, named FAT32 (File Allocation Table).
One major advantage of NTFS is that it includes features to improve reliablity. For example, the new technology file system includes fault tolerance, which automatically repairs hard drive errors without displaying error messages. It also keeps detailed transaction logs, which tracks hard drive errors. This can help prevent hard disk failures and makes it possible to recover files if the hard drive does fail.
NTFS also allows permissions (such as read, write, and execute) to be set for individual directories and files.
SS 3
FIRST TERM E-LEARNING NOTE
SUBJECT: DATA PROCESSING CLASS: SS3
SCHEME OF WORK
WEEK TOPIC
REVISION
INDEXES:- Definition, Clustered versus Unclustered indexes
INDEXES:- Dense versus Sparse, Primary and Secondary Indexes, Indexes using Composite Search Keys
MAINTENANCE OF COMPUTER:- Computer Hardware, Process Of Maintaining Hardware
MAINTENANCE OF COMPUTER:- Procedure for Software Maintenance, Software for Hardware and Software Maintenance
DATABASE SECURITY:- Definition and Explanation, Access Control and Encryption
DATABASE SECURITY:- Importance, Integrity and Availability, the Role of a Database Administrator
CRASH RECOVERY:- Introduction to ARIES, other Recovery Related Data Structure.
CRASH RECOVERY:- Definition and Explanation of Check Pointing, Explain Media Recovery
REVISION
EXAMINATION
REFERENCE TEXTBOOK: UNDERSTANDING DATA PROCESSING for SENIOR SECONDARY SCHOOLS BY: DINEHIN VICTORIA
WEEK ONE
REVISION
DEFINITION OF DATA MODEL
Is the process of structuring and organizing data.
TYPES OF DATA MODELS
(1) Flat (2) Hierarchical (3) Network (4) Relational (5) Object-Relational and (6)Star Schema
SIGNIFICANCE OF DATA MODEL
(1) A well-developed data model can foster improved understanding of the organization
(2) Data model helps in structuring and organizing of data
(3) It imposes constraints or limitations on the data placed within the structure
STANDARD DATA MODEL
A standard data model or industry standard data model is a data model that is widely applied in some industry and shared amongst competitors to some degree. Examples are: ISO 10303, ISO 15926, IDEAS GROUP
NORMALIZATION
Is the process of efficiently organizing data in a database by reducing duplication or redundancy and design flaws.
NORMAL FORM
Provide criteria for determining a table’s degree of vulnerability to logical inconsistencies and anomalies.
CLASSES OF NORMAL FORM
1st, 2nd, 3rd, BNC, 4th and 5th normal forms
DETERMINANT OF NORMAL FORM
(1) The minimal number of attributes necessary to support the data requirements of the enterprise
(2) Attributes with a close logical relationship are found in the same relation
(3) Minimal redundancy with each attribute represented only once with the important exception of attributes that form all or part of foreign keys.
EVALUATION
1. Define data model
2. State types of data model
CONCEPT OF KEYS
PRIMARY KEY
Is the attribute used to identify a record uniquely in a table or database
COMPOSITE PRIMARY KEY
Two or more keys used as a primary key
FOREIGN KEY
Is the field or attribute of a table that matches the primary key of another table.
ENTITY RELATIONSHIP DIAGRAM (ERD)
Is the diagram that illustrates the logical structure of a database.
Components of Entity-Relationship (1) Entities (2) Attributes (3) Relationships
ENTITY
Is anything for which data can be written about in a business.
ATTRIBUTES
Are data elements that have the smallest units of data that can be described in a meaningful manner.
RELATIONSHIP
Is an association among the instances of one or more entity types
CARDINALITY
Defines the relationships between the entities in terms of numbers.
TYPES OF RELATIONSHIP
One-to-One, One-to-Many, Many-to-Many
GENERAL EVALUATION
(a) Define data model?
(b) State types of data model
(c) Use the following data to draw a hierarchical data model: Fruit; Orange, Pear, Berry; Lime, Grape,Avocado, Sour Sop, Raspberry, Cranberry [Hints: Lime and Grape are children of Orange, Avocado, and SoarSopare children of Pear while Raspberry and Cranberry are children of Berry]
(a) State five (5) classes of normal forms
(b) Bring the table below to Second Normal Form
TABLE_PURCHASE
CustomerID
StoreID
Purchase Location
1
1
Lagos
1
3
Kano
2
1
Lagos
3
2
Abuja
4
3
Kano
Hint: This table has a composite primary key [CustomerID, StoreID]
WEEKEND ASSIGNMENT
Data models describe ……… data for storage in data management systems (a) structured (b) unstructured (c) integer (d) alphabetic
Which of this is not an example of standard data model (a) ISO 10303 (b) ISO 15926 (c) IDEAS GROUP d) Good shepherd
……….. key is a field in a relational table that matches a primary key of another table (a) foreign (b) surrogate (c) primary (d) candidate
……………. is graphical representation of entities and their relationships to each other (a) Entity-Relationship Diagram (b) Entity-Relationship Picture (c) Entity-Relationship Data (d) Entity-Relationship Symbol
A roof covers a building describes …………relationship (a) one-to-one (b) one-to-many (c) many-to-many(d) none of the above
THEORY
(a) Define the following terms (i) Entity (ii) Attribute (iii) Relationship
(b) What is cardinality?
(c) Mention and explain three types of relationship in ERD with one example each
(a) Define the following (i) Primary key (ii) Foreign key (iii) Composite primary key
(b) Explain the term Normal Form.
(c) Design a database of your choice indicating the primary key and the foreign key
WEEK TWO
INDEXES
DEFINITION
An Index is a copy of database table that has been reduced to certain fields and the copy is always in sorted form. The index also contains a pointer to the corresponding record of the actual table so that the fields not contained in the index can also be read. Index contains a value and a pointer to first record that contains data value.
A Database Index is a data structure that speeds up certain operation on a file. The Operation involves a search key which is the set of record files( in most cases a single field). The elements of an index are called data entries. Data entries can be actual data record. A given file of data records can have several indexes, each with different search keys as showed in the table below.
Customer ID
Name
Address
City
State
Zip
001
Mr Daniel
10,Bale str.
Maryland
Lagos
1011
002
Mrs Okon
5, Oju-ile
Ota
Ogun
1021
003
Mr David
26, Dalemo str.
Ikeja
Lagos
1023
The search engine searches for a value in table or file in two ways. The table scan which is sequential and index which is random.
Indexes are special lookup tables that the database engine uses to speed up data retrieval. An index in a database is similar to an index in the back of a book.
An index table or file consists of records called index entries. It is of the form
Search- key
Pointer
The search key field is used to sort the rows (in the index column) and the pointer field (in index column) indicates where the actual data in the table will be retrieved. When a table has an index it simply means the records in that table has been sorted in one way or the other.
Indexes are automatically created when primary key and unique constraints are defined on table columns.
EVALUATION
1. What is an index?
2. What are data entries?
INDEX CLASSIFICATION
Index can be classified as either clustered or unclustered.
CLUSTERED
Clustered index is an index whose sorting order determines the order of how the rows/records in a table are stored. There could be only one clustered index in a table because there could always be one way of arranging the records in a table at a given time. For example, if you are asked to arrange some tables in a room, you could arrange them in a round form, row form or packed them close together, only one way at a time. Clustered index also means that related values in a table are stored close to each other according to the order of the index.
CLUSTERED INDEX
A Clustered index is when a file is organized so that the ordering of data records is the same as or closes to the ordering of data entries. A clustered index can take place only if the data records are sorted on the search key field. For example, suppose that students records are sorted by age; an index on age that stores data entries in sorted order by age is a clustered index.
Indexes that maintain data entries in sorted order by search key use a collection of index entries, organized into a tree structure to guide searches for data entries. Thus, clustered indexes are relatively expensive to maintain when the file is updated, when data entries are to be moved across pages, and if records are identified by a combination of page id and slot as is often the case, all places in the database that point to a moved record must also be updated to point to the new location.These additional updates can be time consuming.
The table below illustrate a clustered index file:
Student ID
Name
Age
00231364OJ
Olu Jacob
12
00241265AF
Agu Faith
13
00251057AJ
Abiola Joseph
13
00211362MS
Mathew Stephen
14
00251302TB
TjomasBintu
15
UNCLUSTERED INDEX
This an index whose sorting order does not determine the order of how the rows/records in a table are stored. This means that the search keys in the index column is sorted in one order while the actual records or rows are sorted in another order or are not sorted at all.
This is an index that is not clustered. A data file can contain several unclustered index. For example, supposing that students records are sorted by age; and if additional index on gpa field is included, it is called unclustered index.
GENERAL EVALUATION
(1)Explain a database index
(2) Explain clustered index versus unclustered index.
READING ASSIGNMENT
Understanding Data Processing for Senior Secondary Schools by Dinehin Victoria, Page 254.
WEEKEND ASSIGNMENT
………. is a database table that has been reduced to certain fields.a) Table b) An index c) Table model d) Network model
The copy of an index is always in …… form. a) duplicate b) field c) sorted d) domain
The …………index can take place only if the data records are sorted on the search key field. a)unclustered b)insert c) update d) clustered
A …………….. can contain several unclusterd indexes a) data file b) primary c) check d) index
Index contain a value and ……. a)pointer b) sign c) update d) model
THEORY
Differentiate between clustered index and unclustered index.
State two reasons why clustered index is expensive to maintain.
What is an index?
WEEK THREE
INDEXES
DENSE VERSUS SPARSE INDEXES
DENSE INDEX
This is said to be dense if it contains (at least) one data entry for every search key value that appears in a record in the indexed file.
In a dense index, index record appears for every search key value in the file or table. That is every search key in the index column has a particular record it will point to in the table or file.
For example,
10101
12121
15151
22222
32343
10101
OJO
Maths
90000
12121
ANYAOGU
DP
75000
15151
ROBERT
ICT
65000
22222
ADEREMU
Computer
60000
32343
TUNDE
Music
50000
From the figure above, we can see that each search key in the index has a particular record that it point to in the base table
SPARSE INDEX
In a sparse index, each search key does not have a corresponding record it point to but may point to a group of records in the base table. For example:
10101
22222
32343
10101
OJO
Maths
90000
12121
ANYAOGU
DP
75000
15151
ROBERT
ICT
65000
22222
ADEREMU
Computer
60000
32343
TUNDE
Music
50000
From the figure above, search keys such as 12121, 15151 do not have corresponding records in the index but you can search for them through 10101 key to retrieve their records in the base table.
A Sparse Index contains one entry for each page of records in the data file. The index record contains the search key and a pointer to the first data record with that search key value. A Sparse index must be clustered and it is smaller than a dense index.
PRIMARY AND SECONDARY INDEX
PRIMARY INDEX
Primary index is an index defined on a primary key column(s) of a relation with unique constraint which guarantee that the field will not contain duplicate values and determine the order of how the records are physically stored on the disk. Note that this is also called clustered index.
This is an index on a set of fields that includes the primary key. Primary index contains records that are usually clustered. A primary index is created for the primary key of a table.
SECONDARY INDEX
Secondary index is an index defined on a non-key field which may contain duplicate values and as such does not determine the order of how the records are physically stored on a disk. It is also called non-clustered index.
For example, in student database, student ID is used to look up for a student as the key, however, one might want to look up for a student using LastName by creating secondary index on that column.
Secondary index is an index that is not a primary index i.e. it does not include primary key. Secondary index can be created on non- key attribute. It contains duplicate data entries.
A Unique index is an index in which the search key contains some candidate key.
EVALUATION
Distinguish between dense index and sparse index
Explain primary and secondary index
INDEXES USING COMPOSITE SEARCH KEYS
Composite search keys or concatenated keys are when the search key for an index contain several fields. For example, considering a collection of employee records with field name, age and salary stored in sorted order by name. if the search key is composite, an equality query is one in which each field in the search key is bound to a constant. For example, we can ask to retrieve all data entries with age = 20 and sal = 10, the hashed file organization supports only equality queries since a hash function identifies the bucket containing desired records only if a value is specified for each field in the search key.
The search key for an index can contain several fields, such keys are called Composite Search Keysor Concatenated Keys.
Range Queryis the one in which not all fields in the search key are bound to constants. For example, we can ask to retrieve all data entries with age = 20; this query implies that any value is acceptable for the sal _eld. Another example of a range query is when ask to retrieve all data entries with age < 30 and sal> 40
GENERAL EVALUATION
Differentiate between a unique index and a range query.
What is the difference between primary and secondary indexes?.
READING ASSIGNMENT
Understanding Data Processing for Senior Secondary Schools by Dinehin Victoria, Page 254.
WEEKEND ASSIGNMENT
………. is an index in which the search key contains some candidate key. a) Unique index b) An index c) composite d) sparse index
…… can be created on a non- key attribute. a) primary index b) dense index c) secondary index d) sparse index
A sparse index contains one entry for each ……of records in the data file. a) page b) table c) row d) column
4. ………is the one in which not all fields in the Search key are bound to constant. a) dense index b) composite search key c) secondary index d) range query
5. ……. is when the search key for an index contain several fields. a) primary index b) composite search key c) secondary index d) unique index
THEORY
1. Create a student table with the following fields: name, age, and scores of 5 records. Create an index using a composite keys name and age. (show the table and SQL statements)
2. Discuss the different types of indexing.
3. Differentiate between a unique index and a range query.
4. What is composite search key?
WEEK FOUR
MAINTENANCE OF COMPUTER HARDWARE I
Maintenance of computer hardware is a way of taking care, repairing and replacing broken and failing computer hardware.
Maintenance is necessary on computer to avoid hardware failure or loosing valuable information and most times, hardware breaks without notice. Excess heat accelerates the deterioration of the delicate circuits in the system. Dust and dirt are the most common cause of overheating. Thus, cleaning a case is done to prevent components from overheating.
Computer hardware components attract dust, dirt, lint, carpet fibres, pet hair and smoke particles. The air from the computer cooling fan contains grime which settles on the components and causes overheating which eventually results in permanent hardware failure.
As a result of this, complete cleaning should be done at least once a year and if the computer is used in hot, dusty moist environment, cleaning must be performed more frequently.
PROCESS OF MAINTAINING COMPUTER HARDWARE
GENERAL COMPUTER CLEANING
Step 1: Always shut down, power off the system before carrying out any computer maintenance.
Step 2: Never sprays any liquid onto any computer component. Spray or pour the liquid on a lint – free cloth and wipe the PC with the cloth. Avoid product with certain cellulose which will leave streaks on your computer equipment. The use of paper towels or an old rag to clean delicate surfaces of a computer should be discouraged because paper products contain cellulose which can scratch delicate surfaces of your hardware.
Step 3: Use vacuum cleaner to remove dirt, dust, food and hair from keyboards.it is advisable to wear an anti – static wrist strip to reduce the transfer of static electricity from the body to the computer.
Step 4: Do not apply cleaning solution including water directly to computer components.
Step 5: Do not use your breath to blow the dust off the components because your breath contains moisture and the components are not built to be rust- proof.
Step 6: Sometimes, it is necessary to replace fans or physically wipe some computer components.
Step 7: Do not use anything wet or damp inside the computer case.
Step 8: Do not let any component or circuit board inside the computer case get wet or damp.
Step 9: Do not attempt to clean the motherboard with a cloth as it may damage the electrical components. Use a slightly moist cloth to wipe off dust and grime inside the computer case.
Step 10: Do not allow any drink around the machinery.
Step 11: Avoid vibrations and shocks.
TOOLS FOR CLEANING COMPUTER HARDWARE
Aclean non-abrasive cloth such as microfiber, cotton, T-shirt, cotton handkerchief should be used and avoid using paper towels, dish towels, facial tissue, old rag.
Portable vacuum.
Appropriate cleaning solution.
Cotton swabs.
Foam swabs.
DVD or CD-ROM cleaner.
EVALUATION
State the steps involve in maintaining a computer hardware
Mention six tools used in cleaning computer hardware
HOW TO CLEAN YOUR MOUSE
Step 1: Disconnect the mouse cable from the back of the computer case.
Step 2: Lightly dampen a cleaning cloth with isopropyl alcohol and wipe down the outside of the
computer mouse an mouse pad.
Step 3: Remove the bottom cover of the mouse. To this, turn it over and note the directional arrows that indicate the direction of rotation, or how to slide it off. Press with your fingers in the direction of the arrows and then turn the mouse right side up, letting the cover and mouse ball drop into your hand.
Step 4: Wipe the computer mouse ball with a lint-free cloth dampened with isopropyl alcohol. Put it aside.
Step 5: Dampen a swab with isopropyl alcohol and clean between, around and on top the keys. Change swabs as they become dirty. You may need several swabs.
Step 6: Replace the mouse ball and cover.
Step 7: Wipe the mouse cord. Lightly dampen a cleaning cloth with mild soap solution and gently pull the cord through the cloth.
Step 8: Plug the mouse back into the computer.
HOW TO CLEAN YOUR MONITOR
Step 1: Unplug the power supply cord and cable from the back of the monitor and allow it to cool for at least 20 minutes.
Step 2: Vacuum the outside of the monitor, particularly the cooling grooves, holes or slots in the top surface where heavy dust or other debris may have collected. Blow compressed air in short puffs at an angle to the monitor surface. The goal is to remove dust and dirt without letting anything fall into the ventilation holes.
Step 3: Lightly dampen a cloth with a mild soap solution and wipe down the outside plastic portions of the monitor.
Step 4: Clean the monitor cables and power cord while they are disconnected. Lightly dampen a cloth with mild soap solution and gently pull the cables and cords through the cloth.
Step 5: Check the documentation or call the manufacturer to find out if your monitor screen has anti-glare, or other delicate coatings. If so, ask the manufacturer or cleaning instructions. If it does not have these special coatings you may spray a window cleaner unto a lint-free cloth and wipe it clean. Do not spray directly onto the screen. Chemicals may drip inside the monitor and damage it.
Step 6: For dusty or dirty manufacturing environments use a computer dust cover to protect the monitor
HOW TO CLEAN A KEYBOARD
Step 1: Remove the cable from the back of the computer case.
Step 2: Use a vacuum cleaner to remove debris between the key. If no vacuum is available, turn the keyboard upside down and gently tap on the back side dislodge debris.
Step 3: Aim between the keys and compressed air to remove remaining dust and debris. Use short puffs of air applied at about a 30-45 degree angle to the keyboard surface. Alternate between blowing the keys and tapping the keyboard upside down to dislodge particles until it is clean.
Step 4: Lightly dampen a cloth with a mild soap solution and wipe down the outside of the keyboard. Do not spray soap solution directly onto the keyboard.
Step 5: Dampen a swab with isopropyl alcohol and clean between, around and on top of the keys. Change swabs as they become dirty. You may need several swabs.
Step 6: Wipe the keyboard cord. Lightly dampen a cleaning cloth with mild soap solution and gently pull the cord through the cloth. Dry the cord with a dry cloth.
Step 7: For dusty or dirty manufacturing environments a good keyboard cover is recommended.
BATTERY CHARGING AND REPLACEMENT
This can be divided into two types which are:
Battery charging and replacement for laptop
Battery charging and replacement for PC that used UPS.
HOW TO CHARGE A LAPTOP BATTERY
Plug your laptop into the socket and you can leave it there whenever possible.
You can recharge your laptop’s battery whether the battery is fully drained or not.
There is no need to fully drain your laptop’s lithium-ion battery every time you use it.
Lithium-ion battery have a rapid-charging option. This option is available either on a custom tab inside the Power Option dialog box or from special battery software that came with your laptop.
Do not over charge the battery, charge the battery when is getting low between 20%- 10% and do not dry the battery.
FOR PC THAT ARE USING UPS
The battery needed to be fully charge before use at least for 4 to 6 hours.
Ensure that the UPS is kept in contact o the its electrical ground at all times. Do not over load
Do not let the UPS shut down by itself because it can damage battery.
HOW TO CLEAN A DVD DRIVE
1. Purchase DVD laser cleaning kit. The kit is comprised of a single disc that is design to spin in your drive and remove all dust from the lens.
2. Place the CD/DVD laser lens cleaning disc inside your DVD drive’s tray. Close the tray and allow the CD spin in the drive. As it spins, it will clear your lens of most, if not all, of the dust that is on it.
3. Purchase a can of spray air. As an extra precaution, open your drive’s disc tray and gently spray a can of spray air into it. This will remove any of the big pieces of dust that may be lurking inside the tray.
GENERAL EVALUATION
1. Explain steps for cleaning the following (i) Keyboard (ii) Monitor
2. List steps to clean DVD drive lens.
READING ASSIGNMENT
Understanding Data Processing for Senior Secondary Schools by Dinehin Victoria Pages 245 - 250
WEEKEND ASSIGNMENT
1. Maintenance is necessary on computer to avoid ……….
a) hardware failure b) stealing c) invasion d) crime
2. Excess heat accelerates the deterioration of the delicate ……… in the system. a) vacuum b) transistors c) circuits d) particles
3. Dust and dirt are the most common cause of ……… a) leakage b) overheating c) breakage d) spooling.
4. ……….. is used to remove dust, dirt and hair from the keyboard. a) Vacuum cleaner b) Brush c) Old rag d) Paper towels
5. It is advisable to wear an ………… to reduce transferring static electricity from your body to the computer. a) hand glove b) anti – static wrist strip c) coat d) dust cover
THEORY
Explain the steps in cleaning the following: i) Mouse ii) Keyboard iii Monitor iv) DVD drive lens
State six tools used in cleaning computer hardware.
WEEK FIVE
MAINTENANCE OF COMPUTER II
Maintenance is highly essential in order to prolong its contributing functionality.
SOFTWARE MAINTENANCE
The maintenance of programs inside the computer system such as virus, a spyware removal, back up software and a registry removal, cleaner. Every PC should be installed with an anti virus, a spyware removal application back up and a registry cleanser.
Some helpful Tips
Always scan your system once a week.
The hardware should also be defragmented at least once a month.
Delete all temporary files and cookies at regular interval.
TYPES OF SOFTWARE MAINTENANCE
Corrective Maintenance
Perfective Maintenance
Adaptive Maintenance
Preventive maintenance
CORRECTIVE MAINTENANCE
This type of maintenance involves developing and deploying solution to problems that occur during usage of a software program. For instance, when an error message comes up on the screen or program is hanging or freezing or crashing, this implies that corrective software maintenance is needed. A computer programmer is employed to work on a more permanent solution to the problems.
PERFECTIVE MAINTENANCE
This is a measure taken by computer programmer to upgrade the way a software programs function or how fast it processes, requests, develop software menu layouts and command interface so as to ensure that the program has zero tolerance for flaws.
ADAPTIVE MAINTENANCE
It takes care of the changes that occur in software development. For instance, if there is a change in processors speed, thus change will invariably affect how the software performs on a single computer software interfaces with other software programs. So changes in one program necessitates changes in other programs.
PREVENTIVE MAINTENANCE
This is a situation whereby computer programmers try to prevent problems with software programs before they occur. They seek to prevent corrective maintenance as well as anticipating adaptive maintenance needs before users encounter problems. This is done by test running their programs to ensure that the software can handle high data loads and other stressful opearatiobn without difficulties. Computer programmers also ensure compatibility by testing the software with other programs users that are likely to use their software.
PREVENTIVE MAINTENANCE ACTIVITIES INCLUDE THE FOLLOWING:
Installing anti virus protection software and update
Install firewall on your computer
Keep computer registry up to date.
Make sure your operating system is up to date
Delete cookies
EVALUATION
Discuss the four types of software maintenance.
State five benefits of software maintenance.
BENEFITS OF SOFTWARE MAINTENANCE
It promotes fully functional and highly reliable computer.
If preventive maintenance operations are carried out regularly, a PC will never run slowly or have programs that changes or freezes the computer.
When programs like CC cleaners or disk cleanser is used to clean up your hard drive , and also run Defraggler CD disk. Defragment process pack your files that are scattered across your hard drive into configures cluster ( Disk Defragmenter), allowing the file system to locate them easily.
When a PC is protected and maintained by S/W clean up programs, the hrd drive will not be slow and fragmentation will hardly occur.
Registry cleaning.
Problems due to lack of maintenance are reduced.
ROUTINE COMPUTER MAINTENANCE
Routine Computer Maintenance consists of tasks performed on computer daily, weekly or monthly in order to keep the computer running efficiently for a long time.
Disk cleaning should be done weekly to get rid of “trash”.
Defragmentation- Run defrag which is located in terms tools to pull those fragments into one location.
Always update your system
Back up with external hard drive and back-up software.
Physical maintenance, i.e., regular physical cleaning of the hardware components should be observed.
Internet Security: Always run full updated antivirus program when using the internet and also perform full system scan with your anti virusprogram.It is ideal to run a firewall to block potential threats.
Patches and updates: They are regularly released by software companies to tackle security problems found in the programs. System administrators and network technicians should regularly download and apply these updates to ensure that their computersand their networks are protected from hackers, viruses and network intrusions.
Apply repair functions.
COMPUTER MAINTENANCE TIPS
Never turn your computer off with the power switch on until window has shut down.
Get a UPS ( Uninterrupted Power Supply) for your computer.
Back up your data to external hard drives, DVD/ CD Roms, USB/ drives, memory card etc.
Run scan disk and defragment at least once in a month.
Never unplug peripheral from the computer when it is on.
Ensure that you have 300 mbs or 500-600 mbs of free space on your C Drive for window XP, Vista, or Window 7.
Do not allow a lot of programs to load up when you start your computer.
Use anti-virus checker regularly.
Use a firewall program for a high speed internet connection.
Keep track of the software disk you receive with your computer and new peripheral.
Make sure window update is set.
GENERAL EVALUATION
State five routine computer maintenance.
State six computer maintenance tips.
READING ASSIGNMENT
Understanding Data Processing for Senior Secondary Schools by Dinehin Victoria Pages293 - 297.
WEEKEND ASSIGNMENT
1. Which of the following is not a software maintenance? a) Virus b) Spyware c) Hard disk d) Registry removal
2. The software maintenance that involves developing and deploying solutions to problems is .……… a) corrective b) adaptive c) preventive d) perfective
3. The software maintenance that takes care of the changes that occur in software maintenance is called ……... a) adaptive b) corrective c) perfective d) preventive
4. Disk cleaning should be done ……….. a) hourly b) daily c) weekly d) yearly
5. Patches and update are regularly released by software companies to tackle security problems found in …………. a) programs b) hardware c) people ware d) peripheral
THEORY
List and explain the four software maintenance.
State four benefits of software maintenance
State three routine computer maintenance
WEEK SIX AND SEVEN
DATABASE SECURITY
DEFINITION OF DATA SECURITY
Data security is the practice of keeping data protected from corruption and unauthorized access. The focus behind data security is to ensure privacy while protecting personal or corporate data.
It is a means of putting in place the different form of information security controls to protect database against compromise of their confidentiality, integrity and availability.
RISK ASSESSMENT
This will enable you to identify the risks you are faced with and what could happen if valuable data is lost through theft, malware infection or a system crash.
SECURING DATA
Since data can be compromised in many ways, the best security against misuse or theft involves a combination of technical measures, physical security and a well-educated staff. You should implement clearly defined polices into your infrastructure and effectively present them to the staff.
TYPES OF SECURITY CONTROL ON THE DATA
Access Control
Is the selective restriction of access to a place or other resource. The act of accessing may mean consuming, entering, or using. Permission to access a resource is called authorization.
Auditing
Database auditing involves observing a database so as to be aware of the actions of database users. Database administrators and consultants often set up auditing for security purposes, for example, to ensure that those without the permission to access information do not access it.
Authentication
Is the validation control that allows you to log into a system, email or blog account etc. Once logged in, you have various privileges until logging out. Some systems will cancel a session if your machine has been idle for a certain amount of time, requiring that you prove authentication once again to re-enter.You can log in using multiple factors such as a password, a smart card or even a fingerprint.
Encryption
This security mechanism uses mathematical scheme and algorithms to scramble data into unreadable text. It can only be decoded or decrypted by the party that possesses the associated key.
Back Up
This is the process of making copy and archiving of computer data in the event of data losswhich is used to restore the original data.
Password
This is sequence of secret characters used to enable access to afile, program, computer system and other resources.
EVALUATION
1. Explain data security.
2. Explain types of security control on data that you know
IMPORTANCE OF DATA SECURITY
Data security is critical for most business and even home computer users. Client information, payment information, personal files, bank account details- all this information can be hard to replace and potentially dangerous if it falls into the wrong hands. Data lost due to disaster such as a flood of fire is crushing, but losing it to hackers or a malware infection can have much greater consequences.
MAJOR THREATS TO DATA SECURITY
Accident can happen due to human error or software/ hardware error.
Hackers could steal vital information and fraud can easily be perpetrated.
Loss of data integrity.
Improper data access to personal or confidential data.
Loss of data availability through sabotage , a virus , or a worm.
INTEGRITY CONTROLS
BACKUPS
Is the process of copying and archiving of computer data so it may be used to restore the original after a data loss event.
Backupshave two distinct purposes. The primary purpose is to recover data after its loss, be it by data deletion or corruption. The secondary purpose of backups is to recover data from an earlier time, according to a user-defined data retention policy, typically configured within a backup application for how long copies of data are required. Backup is just one of the disaster recovery plans.
APPLICATION SECURITY
Application security is the use of software, hardware and procedural methods to protect application from external threats.
THE ROLE OF DATABASE ADMINISTRATOR IN DATA SECURITY
A database administrator (DB) is a person responsible for the installation, configuration, upgrade, administration, monitoring and maintenance of databases in an organization. The role includes the development and design of database strategies, system monitoring and improving database performance and capacity, and planning for future expansion requirements. They may also plan, co-ordinate an implement security measures to safeguard the database.
A database administrator’s responsibilities can include the following tasks:
Installing and upgrading the database server and application tools.
Allocating system storage and planning future storage requirements for the database system
Modifying the database structure, as necessary, from information given by application developers.
Enrolling users and maintaining system security.
Ensuring compliance with database vendor license agreement.
Controlling and monitoring user access to the database.
Monitoring and optimizing the performance of the database.
Planning for backup and recovery of database information.
Maintaining archive data.
Backing and restoring databases.
Contacting database vendor for technical support.
Generating various reports by querying database as per need.
GENERAL EVALUATION
Define the roles of a database administrator in data security
Define backup and list its importance in data security
READING ASSIGNMENT
Understanding Data Processing for Senior Secondary Schools by Dinehin Victoria Pages 255 - 260
WEEKEND ASSIGNMENT
…………….is the practice of keeping data protected from corruption and unauthorized access. (a) Data measurement (b) Data security (c) Data protection (d) Data control
Which of these is not a type of security control ……?(a) access control (b) auditing (c) encryption(d) storage
.………….. security mechanism uses mathematical schemes and algorithm to scramble data into unreadable text. (a) Encryption (b) Auditing (c) Authentication (d) Auditing
.…………. is the process of copying and archiving data so it may be used to restore original after a data loss (a) Backup (b) Restore (c) Control (d) Saving
…..……… is the computer professional responsible for the configuration, administration and maintenance of a database (a) Programmer (b) System administrator (c) Database administrator (d) System analyst
THEORY
Explain two types of data security control.
Mention five (5) duties of a database administrator.
WEEK EIGHT AND NINE
CRASH RECOVERY
DEFINITION
Crash recovery is the process by which the database is moved back to a consistent and usable state. This is done by rolling back incomplete transactions and completing committed transactions that were still in memory when the crash occurred. When the database is in a consistent and usable state, it has attained what is known as a point of consistency. Following a transaction failure, the database must be recovered.
CONDITIONS THAT CAN RESULT IN TRANSACTION FAILURE INCLUDE:
1. A power failure on the machine causing the database manager and the database partitions on it to go down.
2. A hardware failure such as memory corruption, or disk, CPU, or network failure.
3. A serious operating system error that causes the DB to go down
INTRODUCTION TO ARIES (ALGORITHMS FOR RECOVERY AND ISOLATION EXPLOITING SEMANTICS
ARIES
This is a recovery algorithm designed to work with no-force, steal database approach. It is used by IBM DB2, MS SQL Server and many other database systems.
The three main principles that lie behind ARIES recovery algorithm
Write Ahead Logging: Any change to an object is first recorded in the log, and then the log must be written to a stable storage before changes to the object are written to a disk.
Repeating History during Redo: On restart, after a crash, ARIES retraces the actions of a database before the crash and brings the system back to the exact state that it was in before the crash. The n it undoes the transaction still active at crash time.
Logging Changes during Undo: Change made to the database while undoing transactions are logged to ensure such an action isn’t repeated in the event of repeated restarts.
RECOVERY PROCEDURE AFTER CRASH
The recovery works in three phases
Analysis Phase: The first phase, analysis, computes all the necessary information from the log file.
REDO Phase: The Redo phase restores the database to the exact state at the crash, including all the changes of uncommitted transactions that were running at that point time.
UNDO Phase: The undo phase then undoes all uncommitted changes, leaving the database in a consistent state. After the redo phase the database reflects the exact state at the crash. However, the changes of uncommitted transactions have to be undone to restore the database to a consistent state.
EVALUATION
Define crash recovery.
Explain the term ARIES.
OTHER RECOVERY RELATED TO DATA STRUCTURE
THE WRITE-AHEAD LOG PROTOCOL
Write Ahead Logging (WAL) is family of techniques for providing atomicity and durability (two of the ACID properties) in database systems. In a system using WAL, all modifications are written to a log before they are applied. Usually both redo and undo information is stored in the log. WAL allows updates of a database to be done in one place.
ATOMICITY
This is the property of transaction processing whereby either all the operations of transactions are executed or none of them are executed (all-or-nothing)
DURABILITY
This is the ACID property which guarantees that transactions that have committed will survive permanently.
LOG
A transaction log (also transaction journal, database log, binary log or audit trail) is a history of actions executed by a database management system to guarantee ACID properties over crashes or hardware failure. Physically, a log is a file of updates done to the database, stored in stable storage.
CHECK POINTING
Check pointing is basically consists of storing a snapshot of the current application state, and later on, use it for restarting the execution in case of failure. A check point record is written into the log periodically at that point when the system writes out to the database on disk all DBMS buffers that have been modified. This is a periodic operation that can reduce the time for recovery from a crash.
Check points are used to make recovery more efficient and to control the reuse of primary and secondary log files. In the case of crash, backup files will be used to recover the database to the point of crash.
MEDIA RECOVERY
Media recovery deals with failure of the storage media holding the permanent database, in particular disk failures. The traditional database approach for media recovery uses archive copies (dumps) of the database as well as archive logs. Archive copies represent snapshots of the database and are periodically taken.
The archive log contains the log records for all committed changes which are not yet reflected in the archive copy. In the event of a media failure, the current database can be reconstructed by using the latest archive copy and redoing all changes in chronological order from the archive log.
A faster recovery from disk failures is supported by disk organizations like RAID (redundant arrays of independent disks) which store data redundantly on several disks. However, they do not eliminate the need for archive based media recovery since they cannot completely rule out the possibility of data loss, e.g when multiple disk fail.
GENERAL EVALUATION
Explain crash recovery.
Explain the following terms in crash recovery (i) Media recovery (ii) Check point (iii) The Write - Ahead log protocol
Discuss the concepts of ARIES in crash recovery.
READING ASSIGNMENT
Understanding Data Processing for Senior Secondary Schools by Dinehin Victoria Pages 261 – 267
WEEKEND ASSIGNMENT
The process by which a database is moved back to a consistent and usable state is called………. (a) cash recovery (b) crash recovery (c) past recovery (d) undo recovery
The recovery algorithm that uses no-force and steals approach is …………..
(a) ARIAS (b) ARIES (c) ARREARS (d) ARIS
ARIES works in ……………. Phases (a) 3 (b) 2 (c) 1 (d) 4
Which of these is not a crash recovery type …………
(a) ARIES (b) Media recovery (c) Check pointing (d) UNDO
………. Crash recovery uses backup files (a) Check point (b) ARIES (c) Media recovery
(d) Atomicity
THEORY
Discuss the concept of ARIES in crash recovery.
Explain the difference between media recovery and check point.
Explain the difference between a system crash and a media failure.