The Basics:
Knowing how to use a computer is one of the basic skills
needed to succeed in the workplace. In order to use the computer it is
necessary to understand how the computer works.
Hardware:
Computer hardware is made up of the equipment used to make up
you computer unit. These parts include your monitor, central processing unit
(CPU), keyboard, mouse, printer, and modem.
Definition of Computer:
Computer is an electronic device which is capable of
receiving information (data) in a particular form and of performing a sequence
of operations in accordance with a predetermined but variable set of procedural
instructions (program) to produce a result in the form of information or
signals.
The computer is an electronic machine that performs the
following four general operations:
·
Input
·
Storage
·
Processing
·
Output.
Input:
The input hardware allows you to enter data into the computer.
The input hardware allows you to enter data into the computer.
The primary devices used are the keyboard and
mouse.
Keyboard -
The keyboard looks like the typewriter. A numeric keypad is located to the
right of the keyboard. Numeric keys have the same placement as a 10-key
calculator, which allow the operator to enter data rapidly.
Mouse -
The mouse is a device that allows you to control the movement of the insertion
point on the screen. The operator places the palm of the hand over the mouse
and moves it across a mouse pad, which provides traction for the rolling ball
inside the device. Movement of the ball determines the location of the “I” beam
on the computer screen. When the operator clicks the mouse the “I” beam becomes
an insertion point which indicates the area you are working on the screen. You
can also click the mouse and activate icons or drag to move objects and select
text. There are other input
devices, such as touch screen,
joystick, modem, scanner, and voice recognition systems.
Processing:
The central processing unit or (CPU) is the "Brain" of your computer. It contains the electronic circuits that cause the computer to follow instructions from ROM (read only memory) or from a program in RAM (random access memory). By following these instructions information is processed. The CPU contains three parts.
The central processing unit or (CPU) is the "Brain" of your computer. It contains the electronic circuits that cause the computer to follow instructions from ROM (read only memory) or from a program in RAM (random access memory). By following these instructions information is processed. The CPU contains three parts.
1. Arithmetic
Logic Unit - ALU
is where the "intelligence" of the computer is located. It can add
and compare numbers. To multiply 2 x 4 the computer would add 2 + 2 + 2 + 2.
The ALU makes decisions by determining if a number is greater, less, or equal
to the other number. Processing is completed in nanoseconds, which is a
billionth of a second.
2. Memory - Two types of memory contained on a chip are RAM (Random
Access Memory) or ROM (Read Only Memory). ROM memory has been installed on your
computer by the manufacturer and cannot be altered. ROM is the memory that
determines all the basic functions of the operation of your machine, such as
startup, shut down, and placing a character on the screen. RAM is temporary
memory, which displays the information you are working on. RAM remembers what
you see on your screen while you are working. Today's applications required
large amounts of temporary memory, which may require you to upgrade and add
more RAM memory.
3. Control
Unit -
This is the part of the unit, which directs information to the proper places in
your computer, such as calculation of information by the ALU unit or to store
and print material.
Output:
Output devices such as a monitor or printer make information you input available for you to view or use.
Output devices such as a monitor or printer make information you input available for you to view or use.
A monitor's front is called a screen with a
cathode ray tube (CRT) attached to the screen. Portable computers use a (LCD)
liquid crystal display. Today's super video graphics array (SVGA) monitors
display 256 sharp and clear colors.
Printers used with computers fall into two
categories, impact or nonimpact. Impact printers, such as dot matrix print by
contact against a ribbon making imprint on paper. Inkjet printers print images
by not touching the paper. Ink jet printers spray ink onto the page while a
laser printer works like a copying machine. Laser printers print a higher
quality product but cost from N15,000 and above, whereas an ink jet produces
better quality than a dot matrix and can be purchased from N12,000 and above.
The personal computer user most commonly purchases an ink jet printer for home
use.
2. BITS-AND-BITES & SOFTWARES
Bits and Bites
A computer stores data in units called bits and bytes.
Computer chips called integrated circuits have one of two states, off or on.
Therefore, a system was developed that used only two numbers, 0 and 1. Zero
representing off and 1 representing on. You can think of this as a sort of
light switch. Each switch is called a bit.
Bits are grouped together in sets of eight. Each set of
eight bits is called a byte. Setting different combinations of those eight
"on and off" combinations can be developed to stand for letters
numbers, spaces, and symbols. For practical purposes, think of a byte as one
character. When computers refer to memory or storage they refer to terms using
the following forms of measurement.
8 bits
= 1 byte
1024 bytes = 1 Kilobyte (K)
1024 Kilobytes = 1 Megabyte (MG)
1024 Megabytes = 1 Gigabyte (GB)
1024 bytes = 1 Kilobyte (K)
1024 Kilobytes = 1 Megabyte (MG)
1024 Megabytes = 1 Gigabyte (GB)
Today's hard drives are usually two or more gigabytes of memory and a
floppy disk has 1.44 megabytes of memory.
Software
Computer productivity is determined by
programs which step by step instructions are telling the computer how to
process data. Software can be divided into two groups, system and application.
System software - The operation of your computer is
controlled by system software. As you boot the computer, the system software is
stored in the computer's memory which instructs the computer to load, store,
and execute an application.
Examples of system software are Windows 95 and Windows 98
which use a graphical user interface (GUI) that provides visual clues (icons)
to help the user. DOS, another disk operating system, is text based and not
user friendly.
Professional programmers write a variety of application
software to satisfy needs of the public who wants to perform specific tasks on
their computers. The basic types of application software are word processing,
database, spreadsheet, desktop publishing, and communication.
Word Processing - Word processing is the most
commonly used software in schools, home, and business. A key advantage of word
processing software is that users can make changes such as spelling, margins,
additions, deletions, and movement of text. A beginning computer student should
learn word processing, as it is the basis of most software. Once you have
learned how a word processor functions, you will be able to learn other
software quicker.
Database Software - Database software allows us
to store and manipulate large quantities of data using the computer. For
example, a database can sort the names, addresses, grades and activities for
all of the students in a school. It would be possible to add or delete data and
produce printed reports using the database.
Spreadsheet Software - Spreadsheets store numeric
data that can be used in calculations. A spreadsheet is used to store teacher’s grades and then calculate
student averages. The primary advantage of a computerized spreadsheet is its
ability to redo the calculations should the data it stores be changed.
Calculations can be made automatically as formulas have been preset into the
spreadsheet.
Desktop Publishing - Desktop publishing
applications allow the user to create newspapers, newsletters, brochures, and
similar types of publications. It is similar to word processing except it
allows the user to use text, graphics, pictures, lines, shapes, patterns, and
borders. Desktop publishing requires more skill and computer knowledge of
design and layout.
Presently a user can purchase an integrated program. This
means that a single program performs all applications and allows data to be
transferred from one application to another. Microsoft Office 97, Works, and
ClarisWorks are examples of integrated software. Each application includes a
word processing, data base and spreadsheet section of the software.
There are numerous other applications available. There
are software programs that can be used by musicians to produce musical scores
and play them on a synthesizer, programs that assist an architect in designing
a building, programs that produce the special effects that you see in movies,
and programs that allow e-mail or electronic mail. Every line of work you can
think of has had applications developed, which can ease or enhance its
effectiveness and consistency.
3. COMMUNICATION & SUMMARY OF THE LESSON
Communication
Computers can be connected to
multimedia, such as sound graphics, photographs, and video equipment to
manipulate, input, and generates output, but special software is required.
If a personal computer is within 1,000 feet of another
computer, a cable can directly connect it. If the devices are more than 1,000
feet, the electrical signal weakens. Then a modem is used. A computer is
designed to process data as digital signals, individual electrical pulses
grouped together to represent characters. Telephone equipment was designed to
carry voice, which is made up of a continuous electrical wave called an analog
signal. The purpose of a modem is to send the converted digital signals of a
computer to analog signals to send and then convert the analog signals it
receives to digital to send the message back to the computer. A modem may be a
part of the computer or a stand-alone device that is connected to the computer
and phone line.
Modems can transmit data at rates from 1,200 to 56,200
bits per second (bps) for the personal user.
Summary
Computers are rapidly changing and
changing the world we live in. We used to talk about the changes made in one
generation. Now we see changes from year to year. However, all computers have
several parts in common:
·
input
devices which allow data and commands to be entered into the computer
·
a
means of storing commands and data
·
a
central processing unit which controls the processing
·
a
means of returning the processed information in the form of output
In general, a computer is a machine
which accepts information, processes it and returns new information as output.
As you become familiar with software and hardware you
will have a better understanding of technology for business ad for your home.
Technology is the vast field and learning it will be a lifelong process.
5. DATA PROCESSING CONCEPT
1. Introduction
Each organization, regardless of its size or purpose,
generates data to keep a record of events and transactions that take place
within the business. Generating and organizing this data in a useful way is
called data processing. In this lesson, we shall discuss about various terms
such as data, information, data processing and data processing system.
2. Objectives
After going through this lesson, you will be in a
position to
- define the concepts of data, information and data
processing
- explain various data processing activities
- utilize data processing cycle
- explain data elements, records, files and databases.
3. Data
The word "data" is the plural of datum, which
means fact, observation, assumption or occurrence. More precisely, data are
representations of facts pertaining to people, things, ideas and events. Data
are represented by symbols such as letters of the alphabets, numerals or other
special symbols.
4. Data Processing
Data processing is the act of handling or manipulating
data in some fashion. Regardless of the activities involved in it, processing
tries to assign meaning to data. Thus, the ultimate goal of processing is to
transform data into information.
Data processing is the process through which facts and
figures are collected, assigned meaning, communicated to others and retained
for future use. Hence we can define data processing as a series of actions or
operations that converts data into useful information. We use the term 'data
processing system' to include the resources that are used to accomplish the
processing of data.
5. Information
Information thus can be defined as “data that has been
transformed into a meaningful and useful form for specific purposes”. In some
cases data may not require any processing before constituting information.
However, generally, data is not useful unless it is subjected to a process
through which it is manipulated and organized, its contents analyzed and
evaluated. Only then data becomes information.
There is no hard and fast rule for determining when data
becomes information. A set of letters and numbers may be meaningful to one
person, but may have no meaning to another. Information is identified and
defined by its users. For example, when you purchase something in a departmental
store, a number of data items are put together, such as your name, address
articles you bought, the number of items purchased, the price, the tax and the
amount you paid. Separately, these are all data items but if you put these
items together, they represent information about a business transaction.
6. Data Processing
Activities
As discussed above, data processing consists of those
activities which are necessary to transform data into information. Man has in
course of time devised certain tools to help him in processing data. These
include manual tools such as pencil and paper, mechanical tools such as filing
cabinets, electromechanical tools such as adding machines and typewriters, and
electronic tools such as
Calculators |& computers. Many people immediately
associate data processing with computers. As stated above, a computer is not
the only tool used for data processing; it can be done without computers also.
However, computers have outperformed people for certain tasks. There are some
other tasks for which computer are a poor substitute for human skill and
intelligence.
Regardless to the type of equipment used, various
functions and activities which need to be performed for data processing can be
grouped under five basic categories as shown in Fig. 2.1
(a) Collection
Data originates in the form of events transaction or some observations. This data is then recorded in some usable form. Data may be initially recorded on paper source documents 2.2 and then converted into a machine usable form for processing. Alternatively, they may be recorded
by a direct input device in a paperless, machine-readable form. Data collection is also termed as data capture.
(b) Conversion
Once the data is collected, it is converted from its source documents to a form that is more suitable for processing. The data is first codified by assigning identification codes. A code comprises of numbers, letters, special characters, or a combination of these. For example, an employee
may be allotted a code as 52-53-162, his category as A class, etc. It is useful to codify data, when data requires classification. To classify means to categorize, i.e., data with similar characteristics are placed in similar categories or groups. For example, one may like to arrange accounts data
according to account number or date. Hence a balance sheet can easily be prepared.
After classification of data, it is verified or checked to ensure the accuracy before processing starts. After verification, the data is transcribed from one data medium to another. For example, in case data processing is done using a computer, the data may be transformed from source documents to machine sensible form using magnetic tape or a disk.
(c) Manipulation
Once data is collected and converted, it is ready for the manipulation function which converts data into information. Manipulation consists of following activities:
i. Sorting
It involves the arrangement of data items in a desired sequence. Usually, it is easier to work with data if it is arranged in a logical sequence. Most often, the data are arranged in alphabetical sequence. Sometimes sorting itself will transform data into information. For example, a simple act of sorting the names in alphabetical order gives meaning to a telephone directory. The directory will be practically worthless without sorting.
Business data processing extensively utilizes sorting technique. Virtually all the records in business files are maintained in some logical sequence. Numeric sorting is common in computer-based processing systems because it is usually faster than alphabetical sorting.
ii. Calculating
Arithmetic manipulation of data is called calculating. Items of recorded data can be added to one another, subtracted, divided or multiplied to create new data as shown in fig. 2.2(a). Calculation is an integral part of data processing. For example, in calculating an employee's pay, the hours
worked multiplied by the hourly wage rate gives the gross pay. Based on total earning, income-tax deductions are computed and subtracted from gross-pay to arrive at net pay.
Data originates in the form of events transaction or some observations. This data is then recorded in some usable form. Data may be initially recorded on paper source documents 2.2 and then converted into a machine usable form for processing. Alternatively, they may be recorded
by a direct input device in a paperless, machine-readable form. Data collection is also termed as data capture.
(b) Conversion
Once the data is collected, it is converted from its source documents to a form that is more suitable for processing. The data is first codified by assigning identification codes. A code comprises of numbers, letters, special characters, or a combination of these. For example, an employee
may be allotted a code as 52-53-162, his category as A class, etc. It is useful to codify data, when data requires classification. To classify means to categorize, i.e., data with similar characteristics are placed in similar categories or groups. For example, one may like to arrange accounts data
according to account number or date. Hence a balance sheet can easily be prepared.
After classification of data, it is verified or checked to ensure the accuracy before processing starts. After verification, the data is transcribed from one data medium to another. For example, in case data processing is done using a computer, the data may be transformed from source documents to machine sensible form using magnetic tape or a disk.
(c) Manipulation
Once data is collected and converted, it is ready for the manipulation function which converts data into information. Manipulation consists of following activities:
i. Sorting
It involves the arrangement of data items in a desired sequence. Usually, it is easier to work with data if it is arranged in a logical sequence. Most often, the data are arranged in alphabetical sequence. Sometimes sorting itself will transform data into information. For example, a simple act of sorting the names in alphabetical order gives meaning to a telephone directory. The directory will be practically worthless without sorting.
Business data processing extensively utilizes sorting technique. Virtually all the records in business files are maintained in some logical sequence. Numeric sorting is common in computer-based processing systems because it is usually faster than alphabetical sorting.
ii. Calculating
Arithmetic manipulation of data is called calculating. Items of recorded data can be added to one another, subtracted, divided or multiplied to create new data as shown in fig. 2.2(a). Calculation is an integral part of data processing. For example, in calculating an employee's pay, the hours
worked multiplied by the hourly wage rate gives the gross pay. Based on total earning, income-tax deductions are computed and subtracted from gross-pay to arrive at net pay.
6. DATA PROCESSING CONCEPT- CONTINUATION
iii. Summarizing:
To summarize is to condense or reduce masses of data to a more usable and concise form as shown in fig. 2.2(b). For example, you may summarize a lecture attended in a class by writing small notes in one or two pages.
When the data involved is numbers, you summarize by counting or accumulating the totals of the data in a classification or by selecting strategic data from the mass of data being processed. For example, the summarizing activity may provide a general manager with sales-totals by
major product line, the sales manager with sales totals by individual salesman as well as by the product line and a salesman with sales data by customer as well as by product line.
To summarize is to condense or reduce masses of data to a more usable and concise form as shown in fig. 2.2(b). For example, you may summarize a lecture attended in a class by writing small notes in one or two pages.
When the data involved is numbers, you summarize by counting or accumulating the totals of the data in a classification or by selecting strategic data from the mass of data being processed. For example, the summarizing activity may provide a general manager with sales-totals by
major product line, the sales manager with sales totals by individual salesman as well as by the product line and a salesman with sales data by customer as well as by product line.
iv. Comparing:
To compare data is to perform an evaluation in relation to some known measure. For example, business managers compare data to discover how well their companies are doing. They many compare current sales figures with those for last year to analyze the performance of the company in
the current month.
(d) Managing the Output Results:
Once data has been captured and manipulated following activities may be carried out:
i. Storing:
To store is to hold data for continued or later use. Storage is essential for any organized method of processing and re-using data. The storage mechanisms for data processing systems are file cabinets in a manual system, and electronic devices such as magnetic disks/magnetic tapes in case of computer based system. The storing activity involves storing data and information in organized manner in order to facilitate the retrieval activity. Of course, data should be stored only if the value of having them in future exceeds the storage cost.
ii. Retrieving:
To retrieve means to recover or find again the stored data or information. Retrieval techniques use data storage devices. Thus data, whether in file cabinets or in computers can be recalled for further processing. Retrieval and comparison of old data gives meaning to current information.
(e) Communication:
Communication is the process of sharing information. Unless the information is made available to the users who need it, it is worthless. Thus, communication involves the transfer of data and information produced by the data processing system to the prospective users of such information or to another data processing system. As a result, reports and documents are prepared and delivered to the users. In electronic data processing, results are communicated through display units or terminals.
(f) Reproduction:
To reproduce is to copy or duplicate data or information. This reproduction activity may be done by hand or by machine.
To compare data is to perform an evaluation in relation to some known measure. For example, business managers compare data to discover how well their companies are doing. They many compare current sales figures with those for last year to analyze the performance of the company in
the current month.
(d) Managing the Output Results:
Once data has been captured and manipulated following activities may be carried out:
i. Storing:
To store is to hold data for continued or later use. Storage is essential for any organized method of processing and re-using data. The storage mechanisms for data processing systems are file cabinets in a manual system, and electronic devices such as magnetic disks/magnetic tapes in case of computer based system. The storing activity involves storing data and information in organized manner in order to facilitate the retrieval activity. Of course, data should be stored only if the value of having them in future exceeds the storage cost.
ii. Retrieving:
To retrieve means to recover or find again the stored data or information. Retrieval techniques use data storage devices. Thus data, whether in file cabinets or in computers can be recalled for further processing. Retrieval and comparison of old data gives meaning to current information.
(e) Communication:
Communication is the process of sharing information. Unless the information is made available to the users who need it, it is worthless. Thus, communication involves the transfer of data and information produced by the data processing system to the prospective users of such information or to another data processing system. As a result, reports and documents are prepared and delivered to the users. In electronic data processing, results are communicated through display units or terminals.
(f) Reproduction:
To reproduce is to copy or duplicate data or information. This reproduction activity may be done by hand or by machine.
7. THE DATA PROCESSING CYCLE:
The data processing activities described in our previous lessons are common to all data processing systems from manual to electronic systems. These activities can be grouped in four functional categories, viz., data input, data processing, data output and storage, constituting what is known as a data processing cycle.
(i) Input:
The term input refers to the activities required to record data and to make it available for processing. The input can also include the steps necessary to check, verify and validate data contents.
The data processing activities described in our previous lessons are common to all data processing systems from manual to electronic systems. These activities can be grouped in four functional categories, viz., data input, data processing, data output and storage, constituting what is known as a data processing cycle.
(i) Input:
The term input refers to the activities required to record data and to make it available for processing. The input can also include the steps necessary to check, verify and validate data contents.
(ii) Processing:
The term processing denotes the actual data manipulation techniques such as classifying, sorting, calculating, summarizing, comparing, etc. that convert data into information.
(iii) Output:
It is a communication function which transmits the information, generated after processing of data, to persons who need the information. Sometimes output also includes decoding activity which converts the electronically generated information into human-readable form.
(iv) Storage:
It involves the filing of data and information for future use.
The above mentioned four basic functions are performed in a logical sequence
as shown in Fig. 2.3 in all data processing systems.
8. COMPUTER PROCESSING OPERATIONS:
A
computer can perform only the following four operations which enable computers
to carry out the various data processing activities we have just discussed.
(a) Input/output operations:
A computer can accept data (input) from and supply processed data (output) to a wide range of input/output devices. These devices such as keyboards, display screens, and printers make human-machine communication possible.
(b) Calculation and text manipulation Operations:
Computer circuits perform calculations on numbers. They are also capable of manipulating numerics and other symbols used in text with equal efficiency.
(c) Logic/Comparison Operations:
A computer also possesses the ability to perform logic operations. For example, if we compare two items represented by the symbols A and B, there are only three possible outcomes. A is less than B (A<B); A is equal to B (A=B): or A is greater than B (A>B). A computer can perform such comparisons and the, depending on the result, follow a predetermined path to complete its work. This ability to compare is an important property of computers.
(d) Storage and Retrieval Operations:
Both data and program instructions are stored internally in a computer.
Once they are stored in the internal memory, they can be called up quickly
or retrieved, for further use.
(a) Input/output operations:
A computer can accept data (input) from and supply processed data (output) to a wide range of input/output devices. These devices such as keyboards, display screens, and printers make human-machine communication possible.
(b) Calculation and text manipulation Operations:
Computer circuits perform calculations on numbers. They are also capable of manipulating numerics and other symbols used in text with equal efficiency.
(c) Logic/Comparison Operations:
A computer also possesses the ability to perform logic operations. For example, if we compare two items represented by the symbols A and B, there are only three possible outcomes. A is less than B (A<B); A is equal to B (A=B): or A is greater than B (A>B). A computer can perform such comparisons and the, depending on the result, follow a predetermined path to complete its work. This ability to compare is an important property of computers.
(d) Storage and Retrieval Operations:
Both data and program instructions are stored internally in a computer.
Once they are stored in the internal memory, they can be called up quickly
or retrieved, for further use.
9. DATA PROCESSING SYSTEM:
The activity of data processing can be viewed as a
"system". According to James O'brien a system can be defined as
"a group of interrelated components that seeks the attainment of a common
goal by accepting inputs and producing outputs in an organized process".
For example, a production system accepts raw material as input and produces
finished goods as output.
Similarly, a data processing system can be viewed as a
system that uses data as input and processes this data to produce information
as output.
There are many kinds of data processing systems. A manual
data processing system is one that utilizes tools like pens, and filing
cabinets. A mechanical data processing system uses devices such as typewriters,
calculating machines and book-keeping machines. Finally, electronic data
processing uses computers to automatically process data.
10. DATA ORGANIZATION:
Having discussed the Data Processing Cycle (also called
Information Processing Cycle) and the components of a computer, we will now describe
how data is organized before processing on a computer. Data can be arranged in
a variety of ways, but a hierarchical approach to organization is generally
recommended.
i. Data Item:
A data item is the smallest unit of information stored in
computer file. It is a single element used to represent a fact such as an
employee's name, item price, etc. In a payroll application, the employee
number 170 is a data item. PANKAJ the name is a data item.
ii. Field:
Data items are physically arranged as fields in a
computer file. Their length may be fixed or variable. Since all individuals
have 3 digit employee numbers, a 3-digit field is required to store the
particular data. Hence, it is a fixed field. In contrast, since customer's name
varies considerably from one customer to another, a variable amount of space
must be available to store this element. This can be called as variable field.
iii. Record:
A record is a collection of related data items or fields.
Each record normally corresponds to a specific unit of information. For
example, various fields in the record, illustrated in Fig. 2.4 are employee
number, employee's name, basic salary and house rent allowance. This is the
data used to produce the payroll register report. The first record contains all
the data concerning the employee PANKAJ. The second record contains all the
data concerning the employee REKHA. Each subsequent record contains all the
data for a given employee. It can be seen how each related item is grouped
together to form a record.
iv. File:
The collection of records is called a file. A file
contains all the related records for an application. Therefore, the payroll
file shown in Fig. 2.5 contains all records required to produce the payroll
register report. Files are stored on some medium, such as floppy disk, magnetic
tape or magnetic disk.
v. Database:
The collection of related files is called a database. A
database contains all the related files for a particular application.
11. VARIABLE AND FIXED LENGTH RECORDS
Records
can be of fixed or variable length as depicted in Fig. 2.5
i. Fixed Length Records
In this case, all the records in a file have the same number of bytes. Such a file is called a flat file. If all the records are expected to contain essentially the same quantity of data, then fixed length records are used.
ii. Variable Length Records
In this case, records vary in length. Use of variable length records conserves storage space when the quantity of information, of various records in a file, differs significantly.
12. LOGICAL VERSUS PHYSICAL RECORD
A logical record contains all the data related to a
single entity. It may be a payroll record for an employee or a record of marks
secured by a student in a particular examination. A physical record refers to a
record whose data fields are stored physically next to one another. It is also
the amount of data that is treated as a single unit by the input-output device.
Portions of the same logical record may be located in different physical
records or several logical records may be located in one physical record. For
example, in case of magnetic tape, number of logical records are stored in the
form of a block to increase the data transfer speed and this block is referred
to as a physical record as shown in Fig. 2.6
13. MORE ABOUT DATA PROCESSING
Data
processing refers to the process of performing specific operations on a set of
data or a database. A database is an organized collection of facts and
information, such as records on employees, inventory, customers, and potential
customers. As these examples suggest, numerous forms of data processing exist
and serve diverse applications in the business setting.
Data
processing primarily is performed on information systems, a broad concept that
encompasses computer systems and related devices. At its core, an information
system consists of input, processing, and output. In addition, an information
system provides for feedback from output to input. The input mechanism (such as
a keyboard, scanner, microphone, or camera) gathers and captures raw data and
can be either manual or automated. Processing, which also can be accomplished
manually or automatically, involves transforming the data into useful outputs.
This can involve making comparisons, taking alternative actions, and storing
data for future use. Output typically takes the form of reports and documents
that are used by managers. Feedback is utilized to make necessary adjustments
to the input and processing stages of the information system.
The
processing stage is where management typically exerts the greatest control over
data. It also is the point at which management can derive the most value from
data, assuming that powerful processing tools are available to obtain the intended
results. The most frequent processing procedures available to management are
basic activities such as segregating numbers into relevant groups, aggregating
them, taking ratios, plotting, and making tables. The goal of these processing
activities is to turn a vast collection of facts into meaningful nuggets of
information that can then be used for informed decision making, corporate
strategy, and other managerial functions.
14. DATA AND INFORMATION & CHARACTERISTICS OF VALUABLE INFORMATION
DATA AND INFORMATION:
Data
consist of raw facts, such as customer names and addresses. Information is a
collection of facts organized in such a way that it has more value beyond the
facts themselves. For example, a database of customer names and purchases might
provide information on a company's market demographics, sales trends, and
customer loyalty/turnover.
Turning
data into information is a process or a set of logically related tasks
performed to achieve a defined outcome. This process of defining relationships
between various data requires knowledge. Knowledge is the body or rules,
guidelines, and procedures used to select, organize, and manipulate data to
make it suitable for specific tasks. Consequently, information can be
considered data made more useful through the application of knowledge. The
collection of data, rules, procedures, and relationships that must be followed
are contained in the knowledge base.
CHARACTERISTICS OF VALUABLE
INFORMATION:
In
order for information to be valuable it must have the following characteristics,
as adapted from Ralph M. Stair's book, Principles of Information
Systems:
1. Accurate. Accurate information is
free from error.
2. Complete. Complete information
contains all of the important facts.
3. Economical. Information should be
relatively inexpensive to produce.
4. Flexible. Flexible information can
be used for a variety of purposes, not just one.
5. Reliable. Reliable information is
dependable information.
6. Relevant. Relevant information is
important to the decision-maker.
7. Simple. Information should be simple
to find and understand.
8. Timely. Timely information is
readily available when needed.
9. Verifiable. Verifiable information
can be checked to make sure it is accurate.
15. DATA MANAGEMENT
Data
are organized in a hierarchy that begins with the smallest piece of
data used by a computer—for purposes of this discussion, a single character
such as a letter or number. Characters form fields such as names, telephone
numbers, addresses, and purchases. A collection of fields makes up a record. A
collection of records is referred to as a file. Integrated and related files
make up a database.
An
entity is a class of people, objects, or places for which data are stored or
collected. Examples include employees and customers. Consequently, data are
stored as entities, such as an employee database and a customer database. An
attribute is a characteristic of an entity. For example, the name of a customer
is an attribute of a customer. A specific value of an attribute is referred to
as a data item. That is, data items are found in fields.
The
traditional approach to data management consists of maintaining separate data
files for each application. For example, an employee file would be maintained
for payroll purposes, while an additional employee file might be maintained for
newsletter purposes. One or more data files are created for each application.
However, duplicated files results in data redundancy. The problem
with data redundancy is the possibility that updates are accomplished in one
file but not in another, resulting in a lack of data integrity. Likewise,
maintaining separate files is generally inefficient because the work of
updating and managing the files is duplicated for each separate file that
exists. To overcome potential problems with traditional data management, the
database approach was developed.
The
database approach is such that multiple business applications access the same
database. Consequently, file updates are not required of multiple files.
Updates can be accomplished in the common database, thus improving data
integrity and eliminating redundancy. The database approach provides the
opportunity to share data, as well as information sources. Additional software
is required to implement the database approach to data management. A database
management system (DBMS) is needed. A DBMS consists of a group of programs that
are used in an interface between a database and the user, or between the
database and the application program.
16. DATABASE MODELS
The structure of the relationships in
most databases follows one of three logical database models:
hierarchical, network, and relational.
A
hierarchical database model is one in which the data are organized in a
top-down or inverted tree-like structure. This type of model is best suited for
situations where the logical relationships between data can be properly
represented with the one-parent-many-children approach.
A
network model is an extension of the hierarchical database model. The network
model has an owner-member relationship in which a member may have many owners,
in contrast to a one-to-many-relationship.
A
relational model describes data using a standard tabular format. All data
elements are placed in two-dimensional tables called relations, which are the
equivalent of files. Data inquiries and manipulations can be made via columns
or rows given specific criteria.
Network
database models tend to offer more flexibility than hierarchical models.
However, they are more difficult to develop and use because of relationship
complexity. The relational database model offers the most
flexibility, and was very popular during the early 2000s.
17. DATABASE MANAGEMENT SYSTEMS
As
indicated previously, a database management system (DBMS) is a group of
programs used as an interface between a database and an applications program.
DBMSs are classified by the type of database model they support. A relational
DBMS would follow the relational model, for example. The functions of a DBMS
include data storage and retrieval, database modifications, data manipulation,
and report generation.
A
data definition language (DDL) is a collection of instructions and commands
used to define and describe data and data relationships in a particular
database. File descriptions, area descriptions, record descriptions, and set
descriptions are terms the DDL defines and uses.
A
data dictionary also is important to database management. This is a detailed
description of the structure and intended content in the database. For example,
a data dictionary might specify the maximum number of characters allowed in
each type of field and whether the field content can include numbers, letters,
or specially formatted content such as dates or currencies.
Data dictionaries are used to provide a standard definition of terms
and data elements, assist programmers in designing and writing programs,
simplify database modifications, reduce data redundancy, increase data
reliability, and decrease program development time.
The
choice of a particular DBMS typically is a function of several considerations.
Economic cost considerations include software acquisition costs, maintenance
costs, hardware acquisition costs, database creation and conversion costs,
personnel costs, training costs, and operating costs.
Most
DBMS vendors are combining their products with text editors and browsers,
report generators, listing utilities, communication software, data entry and
display features, and graphical design tools. Consequently, those looking for a
total design system have many choices.
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