ICS101 - Methods of Data Storage - Module 2

Week 3:

Methods of Data Storage

Data storage is the holding of data in an electromagnetic form for access by a computer processor. There are two main kinds of storage:

Primary storage is data that is held in random access memory (RAM) and other memory devices that are built into computers.

Secondary storage is data that is stored on external storage devices such as hard disks, tapes, CD's.

The table below summarizes the main methods of data storage

Method	Description
Hard disks	Often called a disk drive, hard drive or hard disk drive, this method of data storage stores and provides relatively quick access to large amounts of data. The information is stored on electromagnetically charged surfaces called 'platters'.
Floppy disks	A floppy disk is a type of magnetic disk memory which consists of a flexible disk with a magnetic coating. Almost all floppy disks for personal computers now have a capacity of 1.44 megabytes. Floppy disks are readily portable, and are very popular for transferring software from one PC to another. They are, however, very slow compared to hard disks and lack storage capacity. Increasingly, therefore, computer manufacturers are not including floppy disk drives in the products as a built-in storage option.
Tape storage	Tape is used as an external storage medium. It consists of a loop of flexible celluloid-like material that can store data in the form of electromagnetic charges. A tape drive is the device that positions, writes from, and reads to the tape. A tape cartridge is a protectively-encased tape that is portable.
Optical disks	An optical disc is a storage medium that can be written to and read using a low-powered laser beam. A laser reads these dots, and the data is converted to an electrical signal, finally converted into the original data.
CD-R	Compact Disc-Recordable ("CD-R") discs have become a universal data storage medium worldwide. CD-Rs are becoming increasingly popular for music recording and for file storage or transfer between personal computers. CDR discs are write-once media. This means that - once used -they cannot be erased or re-recorded upon. CD-R discs can be played back in any audio CD player or CD-ROM drive, as well as many DVD players and drives.
CD-RW	Compact Disc-Rewritable (CD-RW) disks are rewritable and can be erased and re-recorded upon over and over again. CD-RW discs can only be used on CD players, CD-ROM drives, and DVD players and drives that are CD-RW playback-compatible.
DVD	A DVD (Digital Versatile Disc or Digital Video Disc) is a high density optical disc with large capacity for storage of data, pictures and sound. The capacity capacity is 4.7 GB for single sided, single layer DVD disc - which is approximately 7 times larger than that of a compact disc.

INFORMATION NEEDS AND INFORMATION SEEKING BEHAVIOUR

What is an information need?

According to Wikipedia, information need is an individual or group’s desire to locate and obtain information to satisfy a conscious or unconscious need. The “information” and “need” in “information need” are inseparable. Needs and interest call forth information.

The concept of information needs was coined by an American information scientist, Robert S. Taylor in his article “ The process of asking questions” published in American Documentation now Journal of the American Society of Information Science and Technology.

In his paper, Taylor attempted to describe how an inquirer obtains an answer from an information system, by performing the process consciously or unconsciously. Also he studied the reciprocal influence between the inquirer and a given system.

According to Taylor, Information needs have four levels:

1. Conscious and unconscious need for information not existing in the remembered experience of the investigator. It is the actual but unexpressed need for information.
2. The conscious mental description of an ill-defined area of indecision. In this level, the inquirer might discuss with somebody in a particular field to get an answer.
3. At the researcher’s level, he forms a rational statement of his question. This statement is a rational and unambiguous description of the inquirer’s doubt.
4. The question as presented to the information system.

The need for information in these modern times cannot be overemphasized. To thrive in this modern era, one needs a variety of information, no matter how one is versed in a field or profession. Information plays a significant role in our professional and personal lives. People need information to work properly in their fields. For instance information needs and information seeking behavior of academics have been a popular area of research for the information scientist (Majid and Kassim, 2000). Zhang (1998) stresses that a thorough understanding of users’ information needs and information seeking behavior is fundamental to the provision of successful information service.

INFORMATION SEEKING BEHAVIOUR

Information seeking behavior result from the recognition of a need (s) perceived by the user. It is a conscious attempt on the part of the user in satisfying a particular type of need. The behavior elicited by the user is tailored towards the satisfaction of that particular need. The behavior may take several forms: For example the user may make demands on formal systems that are customarily defined as information systems; such as libraries, On-line services, information centers or upon systems which perform information and non-information functions. On the other hand, the user may seek information from other people rather from systems.

INFORMATION SYSTEMS DEVELOPMENT

An information system is defined as a means of providing information in such a way that it will be most useful to the persons for whom it is intended (Tiamiyu, 2003). In other words, an information system comprises of complementary activities that are performed towards a common objectives of facilitating information flow within a community, department or unit within an organization.

Information systems are usually established to facilitate such activities as the creation, organization, storage, retrieval, transfer, computation and use of data. Such activities require material and human resources with a technology to create and process data into more valuable data and information.

Information systems vary greatly in their objectives, scope and complexity. For instance in an organization, an information system comprises of smaller interconnecting sub-systems that serve the needs of particular departments, units, workgroups or personnel in the organization. An organization provides the forum where human, paper-based (manual), computerized and other information systems overlap and interface with one another across departments and units.

The various departments and units that can make up an organizational information system include the following:

1. Central administration department including strategic planning, finance, personnel and public relations.
2. Production department
3. Sales /marketing, purchasing and inventory department.
4. Research and development department.

Each of these units has overlapping functions whereby the output of one serves as an input to another i.e they interface with one another.

COMPONENTS OF AN INFORMATION SYSTEM

An information system is composed of all the components that collect, manipulate and disseminate data or information. It includes hardware, software, people, communication systems, procedures and data itself. The activities of an information system centre on inputting data, processing of data into information, storage of data and information and the production of output for the end users such as Management report.

The components of an information system are outlined below:

• Human Resources: This constitutes the organizational personnel who act as decision makers, operational level staff, data collectors, computer system operators and managers.
• Socio-organizational framework: It comprises policies, procedures and social networks governing the relationships among personnel; between personnel and the organization; between personnel and their work; between personnel and information; and between personnel and data processing equipment.
• Computer and telecommunication hardware: Computer hardware and telecommunication facilities are needed to facilitate the inputting, processing and storage of data. It could also aid the transfer of data from one source to another.
• Computer software: These are sets of instructions that are used to determine the type of processing to be performed on data and information. For instance there are various applications software which can be utilized for processing data and information.
• Data and information: These are potentially informative symbols recorded as words, numbers or graphs in memos, forms, data sheets, tables, computer files, reports etc.

TYPES OF INFORMATION SYSTEMS

The three major types of information systems are:

• Transaction processing systems
• Management information systems
• Decision support systems

Others are:

• Executive information systems
• Expert system
• Office information system
• Document or record management system

1. Transaction Processing Systems

TPS processes business transaction of the organization. Transaction can be any activity of the organization. Transactions differ from organization to organization. For example, take a railway reservation system. Booking, canceling, etc are all transactions. Any query made to it is a transaction. However, there are some transactions, which are common to almost all organizations. Like employee new employee, maintaining their leave status, maintaining employees accounts, etc.

Transaction processing systems provide speed and accuracy, and can be programmed to follow routines functions of the organization.

The transaction processing system attends to the daily or short term information needs of the organization such as attendance records of the employees. This kind of information is required at the operational level for carrying out the day-to-day operational activities. Due to its capabilities to provide information for processing transaction of the organization, the information system is known as Transaction Processing System or Data Processing System. Some examples of information provided by such systems are processing of orders, posting of entries in bank, evaluating overdue purchaser orders etc.

2. Management Information Systems

Management information system collates, captures data from low level management and summarizes it as a report for management. It produces the output as a report.

These systems assist lower management in problem solving and making decisions. They use the results of transaction processing and some other information also. It is a set of information processing functions. It handles queries as quickly as they arrive. An important element of MIS is database.

A database is a non-redundant collection of interrelated data items that can be processed through application programs and available to many users.

The type of information required by the middle management is known as managerial information. The information required at this level is used for making short term decisions and plans for the organization. Information like sales analysis for the past quarter or yearly production details etc. fall under this category. Management information system (MIS) caters for the information needs of the organization. Due to its capabilities to fulfill the managerial information needs of the organization, Management Information Systems have become a necessity for all big organizations. And due to its vastness, most of the big organizations have separate MIS departments to look into the related issues and proper functioning of the system.

3. Decision Support Systems

These systems assist higher management to make long term decisions. These type of systems handle unstructured or semi structured decisions. A decision is considered unstructured if there are no clear procedures for making the decision and if not all the factors to be considered in the decision can be readily identified in advance.

A computerized decision support system deals with calculations, forecasts, prediction, optimization and simulation in order to support Top Management decisions. It goes beyond providing information to support decision making. A special software is needed to do the analysis.

The information provided by DSS is of strategic value; hence it is used by Management for decision making. For example the trends in revenues earned by the organization are required by the top management for setting the policies of the organization. This information is not required by the lower levels in the organization.

4. EXECUTIVE INFORMATION SYSTEM

This is an information system designed for executives in an organization. They help in strategic decision making. EIS depends on both the MIS and the environment for information. The information can be tit bits not necessarily voluminous. Information of this nature can be about competitors, profitability and other alerting sources.

EIS selectively disseminates information to the top Management of an organization. The information obtained either from within or outside the organization are of strategic importance, and are passed to them real time with no complex analysis. The EIS evaluates the information coming from outside or within the organization to prevent information overload.

5. EXPERT SYSTEM : Evaluating and taking decisions on the part of the executives has led to the development of the expert system. Expert system is designed to make recommendations based on the data that had been fed into it. It simulates a human expert in a particular field in evaluating data and recommending actions to be taken.

6. OFFICE INFORMATION SYSTEM: This comprises of seamless integration of computing and telecommunication office technologies in the office environment within an organization. The OIS is designed to reduce the need for paperwork in an organization, reducing the need for multiple capture of data and making the office environment more pleasurable for office workers. These technologies facilitate speedy and efficient storage, retrieval, delivery and processing of data, documents and messages in the office.

7. DOCUMENT OR RECORDS INFORMATION SYSTEM: This type of system is designed to manage the corporate records of an organization. The computer can be used to manage the records. There are various ways of managing organizational records. These include:

• Extracting information from a document and keyed it into a computer data file for storage.
• Scan the document and later stored on a data file.
• The document or record can be stored on a CD-ROM due to its durability and longevity.

Figure

1.2 - Relation of information systems to levels of organization

INFORMATION SYSTEMS METHODOLOGIES

According to Avison and Fitzgerald (1995) an information system development methodology is defined as a system of procedures, techniques, tools and documentation which help system developers to implement a new system.

There is no standard methodology to be adopted for every problem situation in system development. The main problem for most system analyst is which methodology or which combination of methodologies to adopt in solving a particular problem.

The structured approach to systems development or the traditional approach is an orderly step- by step approach to performing a sequence of activities in the process of developing any type of information. Another name for it is the System Design Life Cycle (SDLC).

The sequence of system development as identified by Jeffery and Lawrence, 1984) are mentioned below: This can be applied from manual to computerized system.

1. PROBLEM DEFINITION AND REQUIREMENT SPECIFICATION: This is the stage during which problems or deficiencies associated with an existing information system are articulated. The problem of the old system will determine the requirement to be met by the proposed system.
2. SYSTEM ANALYSIS AND FEASIBILITY STUDY: The focus is on Analyzing the existing system in detailed and proposing alternative system that could meet the requirement of the new system. The alternatives systems are analyzed to such a depth as to determining which of the alternatives are feasible and cost effective.
3. SYSTEM DESIGN: The detailed physical and logical design of the proposed new system is performed at this stage. The logical design focuses on what the new system will be doing with data, complete description of data and data flows in terms of input, processing and output data. The physical design provides a complete description of all input and output format, data files, databases, forms, data processing equipment, personnel, software specification, system security, control and operational requirement.
4. PROGRAMMING: The software specifications are coded by programmers into a computer program using a particular programming language. The program is comprehensively tested to remove errors. Complete documentation of the computer program and user manual are produced. In the alternative, a ready made software can be purchased that would meet the data processing requirement of the proposed system.
5. IMPLEMENTATION: The objective of this stage is to provide a working system for the organization by developing an organizational environment in which the system will operate. The task performed at this stage involves installing and testing the complete system within the environment of the organization, site preparation, purchase and installation of equipment and software, training of operators and users of the system, conversion of the existing data into formats that can be used by the system. The old system is run concurrently with the new system before final change over to the new system.
6. POST IMPLEMENTATION EVALUATION This is done prior to and after complete change over from the old to the new system. The purpose of this review is to ascertain whether the new system is meeting the requirement as originally set. This evaluation will provide a feedback to the system designer as to the correctness of their analysis and design, and might instigate a new system development.

INFORMATION SYSTEMS CAREERS

Information systems have various career prospects. The careers allows for multi- specialty. A detailed description of each of the careers is listed below:

1. SYSTEM ANALYST: A system Analyst is a person who selects and configures computer information systems for an Organization or business. The system Analyst job begins with determining the understanding the general objectives of the Organization, the system and user requirements. Once the system Analyst has determined the general and specific needs of the system, he can choose an appropriate system that will accomplish the goals of the business.
2. SYSTEM DESIGNER: A system designer is a person who designs, develops and implements the clearly defined information requirement of the new system. This entails planning, designing information systems that integrate hardware, software and communication technologies. Systems designer are usually central to the development and installation of new IT system, which are run in parallel with the old system until all the bugs in the new system are found and resolved.

3. SYSTEM PROGRAMMER: In an IT Organization, a system programmer plays a central role. He installs, customizes and maintains the operating system. He installs or upgrades products that run on the system. Other tasks performed by the system programmer include the following: Planning hardware and software system upgrades and changes in configuration, Training system operators, Performing installation specific customization task, Debugging problems with system software and System wide performance tuning to meet required levels of service.

4. DATABASE SYSTEM ADMINISTRATOR (DBA) The DBA maintains the system software environment for business purposes. He does the day-to-day maintenance of the system to keep them running smoothly. The DBA also ensures the integrity of, and efficient access to data that is stored in the database. Other tasks performed by the DBA include: installing software, adding and deleting users and maintaining user profiles, managing storage devices and printers, managing networks, connectivity and system performance.

5. INFORMATION TECHNOLOGIST: Information technologists operate, maintain and control information systems and equipment. In some organizations they are referred to as information support personnel or communication support specialist.

6. INFORMATION MANAGERS: Information Managers plan, develop coordinate and control information systems, human and material resources needed for the systems and processing. The main role of an information Manager is to coordinate activities, sub systems and services under him. They are also called Director of information services.