Secondary storage devices

In document Business Information Systems 2T (Page 29-34)

COMPUTER HARDWARE AND SOFTWARE

2. Secondary storage devices

Secondary storage devices include the following:

• Floppy disk: Consists of a plastic disk, coated with a magnetic covering and enclosed within a rigid plastic case.

• Hard disk: A magnetic medium that stores data upon a number of rigid platters that are rotated at very high speeds.

• Personal video recorder (PVR): A PVR is a sophisticated video recorder that uses a hard disk drive to store programs. The use of a hard disk drive allows a PVR to offer a range of sophisticated features, such as the ability to ‘pause’ live broadcasts.

• Flash drive: A flash drive is a portable storage device that connects to a computer via a standard USB port. Flash drives have no moving parts, so are reliable and robust.

MANCOSA – BCom ITM Year 2 29 Additional Reading:

For further reading on Primary and Secondary storage devices, turn to pp. 95-100 of Bocij et al.

ACTIVITY

Analyse the Case 3.2 Did IT work? How Wall Street is eradicating down time (Bocij et al., p. 106).

Analyse the case and answer the questions.

After answering the questions, refer to the suggested answers at the end of the study unit.

2.5 COMPONENTS OF A COMPUTER SYSTEM

2.5.1 What is a Computer System?

A computer system is a number of interrelated components including hardware and software that work together with the aim of converting data into information. The components of a computer system include hardware and software.

2.5.2 Computer Hardware What is Computer Hardware?

Computer hardware includes the physical components of a computer system: input devices, memory, central processing unit, output devices and storage devices.

• Input devices. Hardware used to enter data, information or instructions into a computer-based information system.

• Central Processing Unit (CPU): The processor found in a computer system that controls all the computer’s main functions and enables users to execute programs or process data.

• Memory: a temporary means of storing data awaiting processing, instructions used to process data or control the computer systems and data or information that has been processed.

• Output devices: translate the results of processing – output into a human readable form.

• Storage devices: a permanent means of storing data and programs until they are required.

MANCOSA – BCom ITM Year 2 30 Figure 2.1

(Source: Bocij et al, 2008:67)

Further reading

Read on Components of a computer system: Turn to pp.66-68 of Bocij et al.

2.6 TYPES OF COMPUTER SYSTEMS

There are several major categories of computer systems with a variety of characteristics and capabilities. Thus, computer systems are typically classified as:

 Mainframe computers: powerful computers used for large-scale data processing

 Minicomputers computers: computers that offer an intermediate stage between the power and mainframe systems and the relatively low cost of microcomputer systems.

 Microcomputers: computers that are considered less powerful than minicomputers and mainframes, but are more flexible and relatively inexpensive to purchase.

These categories are attempts to describe the relative computing power provided by different computing platforms or types of computer. Therefore, they are not precise classifications.

MANCOSA – BCom ITM Year 2 31 Some experts predict the merging or disappearance of several computer categories. They feel that many midrange and mainframe systems have been made obsolete by the power and versatility of client/server networks of microcomputers and servers. Most recently, some industry experts have predicted that the emergence of network computers and information appliances for applications on the Internet and corporate intranets will replace many personal computers, especially in large organisations and in the home computer market.

ACTIVITY

To understand better the paragraph above on obsolete computer systems, attempt Discussion Question 3 p. 116 of Bocij et al.

Computer systems are most commonly categorised according to size, processing speed and storage capacity.

Further reading

Turn to the paragraph Major categories of computers (Bocij et al., p. 68), which gives a short overview of the various types of computers, (Figure 3.3 on p. 68).

Figure 2.2: Different forms of computer system.

(Source: Bocij et al, 2008: 68)

MANCOSA – BCom ITM Year 2 32 2.7 NETWORKED COMPUTER SYSTEMS

Network computer systems are very important in organisations.

The benefits of network computer systems are:

 Networked computer systems allow end users to communicate electronically and share the use of hardware, software, and data resources.

 Networks of small computers have become a major alternative to the use of larger computer systems, as many organisations downsize their computing platforms. For example, a local area network (LAN) of microcomputers can replace the use of groups of end user terminals connected to a minicomputer or mainframe.

The features of networked computer applications include:

 Networked microcomputer systems are used in place of minicomputers and mainframes;

 Are easy to install, use, and maintain; and provide a more efficient, flexible, lower-cost alternative to large computer systems for many applications; and

 Can share computer power, software, and databases required in time-sharing and resource-sharing applications.

 Networked computers also support work group computing (communicate electronically and share data on joint projects); and

 Are used in transaction processing applications.

Additional Reading

Network computer systems form a vital part of today’s information systems. Increasingly, computers are being networked or interconnected by Telecommunications links with other computer systems. Further reading: Turn to p. 74 of Bocij et al. and read through the paragraph Network Computers.

MANCOSA – BCom ITM Year 2 33 ACTIVITY

The mini case study on p. 75 of Bocij et al., relates how Panalpina uses network computers to reduce costs, please study the paragraph and make notes. Then analyse Case 3.1 “When Systems converge but people don’t” and answer the questions on p.81 as well as Essay Question 1 on p. 116. Take note of the use of computer systems.

ACTIVITY

Work through the following exercises on network computing. Refer to Discussion Question 1 on p 115 of Bocij et al.

Do you think that client/server networks make minicomputers and mainframe computers obsolete?

Explain.

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In document Business Information Systems 2T (Page 29-34)

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