(The prescribed text, Shelly, Cashman and Rosenblatt, covers this area briefly on pages 12-15.)
What do information systems do? What do they consist of? We can consider these questions generally and specifically. To consider generally it is necessary to study many different information systems. A list was provided in the notes for Week 1.
To consider specifically we need to look at the different types of information systems. We can classify information systems in a number of ways.
One of the purposes of an IS is to support decision-making in an organisation. Management at different levels in a business need to make different types of decisions and hence need different types of information provided. The diagram below shows the different management levels.
Let us have a look at the information needs of the different levels of management.
For example, a retail chain store such as K-Mart.
The Sporting Goods department supervisor requires detailed information on the current situation. How many of each brand and size of tennis racquet do we have on the shelves, how many do we have out the back and how many have we on order? This person operates at the lower management and operational personnel level.
The Bendigo branch manager requires less detailed and more general information. For example, the dollar value of each department's sales. The type of questions which need to be supported at this level include how much stock to allocate to each department and how much floor space. This person operates at the middle management level.
The Victorian Head Office executive requires even less detailed information, for example overall branch performance. Decisions supported include whether or not to close a branch or open a new branch, the continued employment of branch managers and the advisability of new advertising strategies. These are top management decisions.
It is interesting to note that each level of management requires access to the same data but the information is more summarised for higher levels of management.
The information systems which correspond to the three levels of management are described below.
use
Transaction = an event or action that is recorded for later use
TPS/OIS is a system designed to perform the paperwork of the organisation efficiently by:
Examples of transactions include sale of a stock item, receipt of a payment from a customer, purchase of a fixed asset.
Examples of the documentation produced include invoices, receipts and
deviation reports.
Deviation reports show out of the ordinary circumstances which require immediate
attention, for example a list of customers who are late in returning a video.
Some examples of transaction processing systems include a payroll system (jpeg image - 158Kbytes), an accounts receivable system (jpeg images - 132Kbytes) and a stock control system (jpeg image - 108Kbytes).
An extended business OIS would include the following systems and related documents:
use:
These are systems designed to provide timely and effective information to support managerial planning and control. Information requirements are predefined for structured decisions - routine events causing routine actions, and some semi-structured decisions - out of the ordinary events requiring some originality in a solution. For example, when processing a sales order the OIS would record the sale, make a deduction from the inventory and possibly update the customer's account balance. The corresponding MIS would produce reports which showed fast or slow selling items, customers whose balance owing was above a predetermined level and items that needed reordering.
In general an MIS analyses and summarises OIS data and presents of this data to management normally in the form of reports.
Rather than being a selection of pre-defined processing options from a menu, a DSS is a collection of applications. The user needs to be familiar with the capabilities of the applications. The data which is used and the order in which the applications are applied to the data are decisions of the user at a particular time.
DSS answer "what if" questions. A spreadsheet application in MS Excel is a simple example of a DSS.
Other uses of DSS:
These systems store decision-making rules about a particular situation in an attempt to simulate a human expert. Human experts develop experience and judgment over long periods of time and use these facilities to determine the most likely results or outcomes. Medical specialists diagnosing illnesses are a good example.
Scenarios suited to an Expert System include:
are information systems that combine many of the features of management information systems and decision support systems. When they were first developed, their focus was on meeting the strategic information needs of top management. Thus, the first goal of executive information systems was to provide top executives with immediate and easy access to information about a firm's critical success factors (CSFs), that is, key factors that are critical to accomplishing an organization's strategic objectives. For example, the executives of a retail store chain
What type of information system is an ERP (enterprise resource planning) system?
What do all these different type of information systems have in common?
Below are examples of different sizes of information systems.
Small
Medium
Large
A small information system may consist of one computer, some software and one person.Total cost may be $3,000.
Compare this to the Macquarie Bank information system which has:
You may question whether this is one information system or many. Consider that one of the prime aims in IT in the Macquarie Bank is to present one face to the client.
Are there differences between the various sized information systems? Consider purpose, components and procedures.
There is an immediate distinction between a single computer IS and a multiple computer IS. Networking of the hardware is an essential component of a multi-computer IS. In fact it is now possible for computers of all types and sizes to talk to each other. The way in which the computers are networked is another means of categorising information systems. We need to consider the location of the data storage and of the processing. In both cases the locations are central or distributed.
Historically both data and processing occurred centrally. An organisation had a data processing department which handled all data storage and processing. Typically users operated dumb terminals throughout the organisation connected to a large central computer which ran the processes which accessed the data. All power existed with the data processing department.
In a distributed data processing environment, smaller, more specialised, networked computers complete particular tasks more efficiently than a general-purpose, centralised computer. In this situation a lot of the processing occurs in the user's terminal. Users control when the processing occurs rather than having to wait their turn in a queue for the central computer. Faster response times are possible.
The present and the future (client/server)
Consider the latest developments in:
State of the art in IS is a business wide system based on a client/server network.
A typical client/server network is made up of many computers. These computers may be of many different types - mainframes, minis, micros. These computers are either clients or servers although a server can sometimes be a client.
A ’client’ computer (typically a PC) intitiates conversations with ’server’ computers. A conversation normally involves a request for data but may also involve a request to run an application or a specific program. The presentation to the user of the results of a conversation is wholly the responsibility of the client. In a typical data-based conversation the language is SQL. The tools used to present the data will be the typical PC application tools eg. spreadsheets, graphics software.
A ’server’ is typically a database server but can also be a repository of applications or a controller of peripheral hardware. The server responds to the request from a client. To respond appropriately a server may have to become the client of another server. The response is down loaded to the client to be manipulated and presented.
Middleware is the network and the software which drives the network.
Application development tools for client/server networks allow the end users to develop their own systems (e.g. Visual Basic). The systems are based on corporate data, with the client not concerned about the whereabouts of the data.
Advantages
Disadvantages
Appropriate applications
Large data files requiring fast response times and strong security and recovery options.
There may be no clear definition of client/server, but there is a clear understanding of the direction it is headed.
The fundamental aim of client/server processing is to provide end users with a single image of the total information systems service. End users should not have to specify how to find data or where each program should run. Ideally they would see one seamless environment and not have to switch back and forth among systems.
Operational: TPS (or OIS), routine functions, structured
input/output
Middle Management: MIS, short-term planning, supervision of
daily operations, semi-structured
Strategic Management : DSS, long-term planning, incorporates
outside data, unstructured
At this stage it would be appropriate for you to consider the two important questions ...
What do information systems do?
What do information systems consist of?
... and contemplate your conception of an IS
Copyright © 2006 Brian Retallick
This page last updated on Friday 24 July 2009 23rd July 2008 by Chris Cope, La Trobe University, Bendigo
