代做ISYS1000 Introduction to Business Information Systems IS Description Framework代写Java编程

ISYS1000 Introduction to Business Information Systems

Information Systems Description Framework (ISDF)

Introduction

The goal of this framework is to provide a structure in which an information system can be described and documented from both an  external viewpoint (independent of the information and  communication technology used to realise it) and from an internal viewpoint (in terms of the information processors, information stores, and communication networks).

Information Systems Concepts

Here is a quick introduction to some of the concepts in information systems description:

•    Information systems description involves investigating an information system to find out more about it and describe and document what you have found using text and diagrams.

•    An information system may process information and may store and retrieve information.

•    An information system has inputs that submit information into the information system.

Inputs and Outputs

o  Inputs may come from people or from external (other) information systems.

o  An information system has outputs that receive information from the information system.

o  Outputs may go to people or to external (other) information systems.

o  An information system has a boundary that defines what is inside and what is outside of the information system.

Information Processors

o  Information processors are the components of an information system that do the information processing (i.e. processing of information).

o  Information processing can be done, for example, by people, machines, and computers running software.

Information Stores

o  Information stores are the components of an information system that store and retrieve information.

o  Information storage can be done, for example, using paper, folders, filing cabinets, computer files, and databases.

Communication Networks

o  Communication (or information) networks are components of an information system that can transfer information from one point to another.

o  Information can be transferred, for example, directly in person, by foot, by post, by computer networks, and by telephone networks.

•    Information systems description can involve a textual description as well as a graphical

representation (i.e. diagrams) of the information system and these complement each other.

•    Information processors (e.g. computers running software or people) are active things in that they do something, i.e. process information, whereas information stores (e.g. databases and filing

cabinets) are passive things in that they don’t do anything on their own. Computers write to and read from databases, just as people write on and read from paper from filing cabinets.

•    Communication (or information) networks in information systems connect information

processors, which may send information across the network to one another. Communication is between two information processors.

•    Information processors can also read and write to information stores, and information flows

across this connection but it is usually not a labelled computer network. We show connections

between information processors and information stores to show which stores they interact with.

•    Inputs flow into information systems from other information systems across networks (of many different types) and information flows out of information systems to other information systems across networks (of many different types). These are called external networks to differentiate them from the internal networks between information processors within the information system.

Information Systems Description Process

To describe information systems, we will follow a simple process (i.e. a sequence of steps) that will break the task down and, hopefully, make it easier for you.

In short, the five (5) steps are:

1.    Provide a general description of the information system

2.    Provide an external description of the information system

3.    Provide an external view of the information system

4.    Provide an internal description of the information system

5.    Provide an internal view of the information system

And now for a more detailed description of the process:

Step 1 - Provide a general description of the information system

•    Provide a general description of the information system by considering and describing: What is the name or title of the information system?

•    Describe the overall information processing and storage function of the information system at a very high level (focusing on its overall purpose or goal)

•    Who (or what other information systems) are the users of the information system? What do these users do with the information system?

•    Give any information about a real-world instance (i.e. example) of this information system.

Step 2 - Provide an external description of the information system

Give a description of the inputs, outputs and boundary of the information system by considering and describing:

•    What inputs does each user provide to the information system (if any)?

•    What outputs does the information system provide to the users (if any)?

•    What is the boundary of the information system? What are the external and internal components of the system boundary?

Step 3 - Provide an external view of the information system

•    Draw a diagram that summarises and represents the information system as described in Step 2. In particular: Use a circle to represent the information system and use arrows going into the system to represent the inputs and arrows coming out of the system to represent the outputs.

•     Label the information system with its name or title.

•    Label the inputs with the name/role of the user (or other information system) that provides them and provide high-level names for the information the users provide.

•    Label the outputs with the name/role of the user or (or other information system) that receives them and provide high-level names for the information the users receive.

Step 4 - Provide an internal description of the information system

Give a description of the information processors, information stores and networks within the information system by considering and describing:

•    What are the information processors inside the information system? What specific information processing does each of these information processors do?

•    What are the information stores inside the information system? What specific information is stored inside each of these information stores?

•    Identify any internal communication networks transferring information within the information system.

•    Identify any external communication networks for input to and output from the information system.

This description should describe the information and communication technologies (both computerised and/ or non-computerised) that can be used to implement (or realise) the information system).

Step 5 - Provide an internal view of the information system

•    Draw a diagram that summarises and represents the information system as described in Step 4.

•    Draw the information processors as cubes or rectangles and label them with descriptive names (e.g. librarian information processor or sales processor).

•    Draw the information stores as cylinders or ellipse and label them with descriptive names (e.g. customer store or product folder).

•    Draw the internal communication networks as lines between the information processors and/or information stores and label them with descriptive names (as needed).

•    Draw the external communication networks as lines between the users and the information processors and label them with descriptive names.

This description should display the information and communication technologies (both computerised and/ or non-computerised that can be used to implement (or realise) the information system).

Style. of Information Systems Description

The textual sections within an information system description are generally not written as paragraphs of text (with the exception of some high-level descriptions). Instead, they are generally written as lists in point form. and the points and sub-points are numbered so they can be easily referred to in other contexts.

The graphical sections within an information system description are generally constructed with a specific notation (i.e. set of symbols like cubes, cylinders, and lines) that have specific meaning. It is important to use the correct graphical notation. These have been briefly explained for the view diagrams above and samples of the symbols are given in the template(s) provided.