Characteristics of Information Systems
3.5.1 Passive and Interactive Information Systems
An information system is a system that provides information according to a user’s requests.
Passive Information Systems
Passive information systems are systems that will answer queries based on the data that is
held within them, but the data is not altered. A simple example would be an electronic
encyclopaedia where queries can be used to search for data and much valuable information
can be learned, but the user is not allowed to alter the data. Another example would be the
student file in a school that can be accessed by members of the teaching staff to find out
where a student is at a particular time of day, or to look up their telephone number in order
to contact the parents. The database of information is a valuable resource but it is not
possible for an ordinary teacher to alter it.
Interactive Information Systems
An interactive system is one that data can be entered for processing which may alter the
contents of the database. An example would be the school secretary updating the
attendance record of a pupil in the pupil file. In commerce, a stock control system in a
supermarket is an interactive information system because it not only gives information like
the price and the description of the goods for the till receipt (passive), but also updates the
number in stock immediately (interactive) so that when the next item is sold the number in
stock has already been altered.
3.5.2 Management Information Systems
A management information system is software that allows the managers within a company
to access and analyse data.
The management within a company, or any other organisation, is usually working on two
levels. These levels may be different levels of management or may be the same people but
with two different tasks. One is the day to day management of the organisation, keeping
track of invoices, ensuring that the business has enough stock, arranging for the workers to
be paid… The other is the strategic management, making decisions about what items of
stock to keep, what new items to stock, what to discontinue…
The first of these management tasks is condition driven. The information system can be
used to trigger decisions that have to be made. A certain item is reported to be low in stock
by the system requiring a decision to be made as to whether to reorder and how many to
The second of these management tasks is to look at the wider picture. To extract
information from the system which can inform wider decisions like should an item be
stocked, which areas of the business are doing well and which are not, which workers are
having to do a lot of overtime which may point to the need to increase staff in that sector.
A good MIS provides managers with appropriate information at the right time. It also
presents information in the right amount of detail according to the level of management.
Shop managers want to know details of sales of all the products in the shop that they
manage. Area managers want details of total sales for each shop in the area for which they
are responsible. Senior managers want details of sales and costs in areas, so that they can
make decisions about, for example, whether or not to open a new shop or close an existing
shop. If a new shop is to be opened, in which area should it be so as to be most profitable?
The MIS needs to organize the data collected over a period of time and to turn the data into
information for the management of the business. Information must be appropriate for the
making of decisions at specified levels of management.
Another example is the information available in a manufacturing business. The manager of
the production line needs to know what orders are outstanding in order to decide the best
order in which to fulfill them. The sales manager needs to know the overall picture of sales
and orders not necessarily details of individual orders. The manager will also need to be
able to answer questions such as
Are sales of some products better than others?
What effect has marketing had on sales?
Has a marketing strategy in one area had a better effect than in another area?
Summarising, a good MIS
provides information that is relevant and accurate for its purpose,
provides information that is sufficiently complete and reliable to instill confidence in the
communicates the information to the right user in time for its purpose and targets its detail
appropriately for the use to which it may be put,
communicates the information to the user in such a way that it is understandable to the
3.5.3 Applications requiring Batch Processing/Rapid Response
This work has been covered in Chapter 1.
A batch processing system is used when the output does not have to be produced
immediately. Other factors are that the application will tend to use a large amount of data,
that processing will tend to be of the same type for each set of data and that human
intervention is not necessary. In module 1 we saw that the perfect example of batch
processing is the payroll system, and nothing has changed because we are in a different
Rapid Response Processing
In module 1 this was referred to as real time processing. Real time processing can be
thought of as being used in process control where the results of the process are used to
inform the next input. A good example would be the control of a robotic machine on the
production line. The other example is in information systems where it becomes necessary to
update the file of information before the next enquiry is dealt with. The classic example is
the airline (or theatre) booking system. If a customer enquires whether there is a seat
available on the flight, and in response to a positive reply decides to buy the ticket, then the
number of tickets now available must be updated before the next person makes an enquiry,
otherwise the second person may be sold the same seat. Similarly, the mail order company
will need to change the number of items in stock before the next query arrives.
In general terms, an examination question will expect the student to be able to decide which
of these two types of processing are most appropriate in a given situation. It is not sensible
to list a number of different applications for each type and to expect students to learn them.
The application in a question may not be on the list and the student would not be
demonstrating an understanding of the concepts even if it was. Far more sensible is to learn
to recognise the characteristics of each of the types of processing in a given application.
3.5.4 Knowledge-based Systems
A knowledge-based system (KBS) a system where all the expert human knowledge
covering a particular topic is brought together and made available to the user through a
computer system which uses the facts in its knowledge base by applying rules that may
sensibly be applied to the knowledge.
Human knowledge encompasses such a massive area of data that it is not reasonable to try
to distill all human knowledge into one computer database. Because of this problem of
volume, knowledge-based systems are restricted to a narrow area of knowledge. It may be
geological patterns in the oil exploration industry, medical diagnosis in the doctor’s waiting
room or personnel information in a company, all are well delineated areas of expertise
where there are no grey areas of whether the data should be included or not. The access to
this knowledge can be very haphazard unless the system follows certain rules. That is why
all expert, or knowledge-based, systems include rule bases which determine how the data
within the system relate to each other. There must be an algorithm, or set of algorithms, for
determining how the rules in the rule base should be applied to the knowledge in the
knowledge base. These algorithms are known as the inference engine which gives a method
for searching and querying the knowledge and rule base. Finally there must be a user
interface which allows the user to interrogate the knowledge base. The user interface will
pass requests on to the inference engine which, in turn, interrogates the knowledge base.
The user interface will prompt the user, often by producing a series of questions each of
which will have a small number of possible answers, and each of which will have the effect
of accessing smaller and smaller areas of the knowledge base. The user interface will also
allow the user to ask for explanations of the reasoning behind the advice that has been
given and the results will give conclusions with the probabilities of those conclusions being
3.5.5 Types of Knowledge-based Systems
Students should be able to discern three different types of knowledge-based system.
The user interface gives a series of questions, each of which has a limited number of
possible answers, each one of which leads to another question. Gradually, the amount of
data in the knowledge base is reduced until there is only a small amount of relevant data
which must provide the answer to the query. A good example is a medical diagnostic
machine. This contains an enormous amount of knowledge about medical conditions. To
read all of it would be a Herculean task. If the user interface asks whether the patient has a
high temperature there are two possible answers which immediately divide the knowledge
base into two parts. A series of similar questions will result in only a small amount of the
knowledge base being relevant. The result may well be more than one possible diagnosis.
In this case, probabilities will be assigned to each diagnosis and a doctor has to finally reach
An advice giving system is one that follows some process being done and then offers advice
on how to proceed if something needs to be done or goes wrong. An example would be a
stock control system which has knowledge of the stock levels of all the items and can offer
advice as to whether further stock should be ordered, when to order, who to order from.
A decision making knowledge-based system is precisely that, a system which understands
what is happening in a system and has been given enough rules to be able to make and
carry out decisions without further intervention. A good example is the stock exchange
share systems used by stock brokers. The computer system keeps a check on the values of
shares constantly. The system has been given certain rules about what to do when share
prices change. For example, the system may have been told to sell the shares owned by a
customer if they fall below a certain value. The reason for this is that, if the shares are
falling sharply, the instruction to sell when a particular value is reached can save the
investor a lot of money. This has become necessary because shares are now traded 24
hours a day in stock markets all over the world, not just in the hours that, for instance, the
London stock exchange is open. This means that if shares fell suddenly in the early hours of
the morning an investor may be bankrupted before the stock market opens again. This has
led to the automated buying and selling of shares by knowledge-based systems. There are
dangers in such an approach. In the 1990s there was a big plunge in the stock markets all
over the world caused by just such an automated approach. Some stock fell triggering some
systems to automatically sell. This put more stock on the market which, in turn, brought the
price down again, which triggered more machines to sell. It was very nearly a disaster
caused by the fact that the knowledge bases were not big enough to see a wide enough
picture. Because the detail was so narrow, the systems had no way of realising that they
were causing the problem and had no rules for dealing with the situation even if they had.
New rules have been written into the knowledge base to make such an occurrence far less
likely to happen again in the future.
3.5.6 Business MIS and Knowledge-based Systems
A management information system is a tool that can be used by a human being in order to
make sense of and glean information from data in a database. A knowledge-based system
is one that can do some of the reasoning that would otherwise have to be done by the
human being, by following the rules in its rule base.
1. Explain the difference between a passive information system and an interactive
information system, giving an example of each. (4)
A. -A passive system is one where the database is not changed
-e.g. This book when it is installed on a network
-An interactive system is one where it is normal for data that is either offered to it or which
it produces will also have the effect of altering the data stored.
-e.g. A system that controls the progress of a computer controlled robot vehicle around a
Notes: The amount of material that is covered in this section is so small that there are very
few questions that can be asked, in fact this just about covers all that can be expected of a
2. A company payroll system uses a personnel file among others.
a) Explain the difference between batch processing and rapid response processing. (2)
b) Explain how batch processing and rapid response processing can both be sensibly used
in the context of the personnel file being used to calculate the payroll. (4)
A. a) -Batch processing is the processing of data by collecting the data and then processing
it in a single batch.
-Rapid response processing is processing where the result of the processing is needed
b) -Payroll needs to be run once per week and..
-requires no human intervention, consequently perfect for batch processing.
-Enquiries by employees need to be handled on a one off basis..
-with the result of the enquiry being made available to the employee immediately.
Notes: The use of different operating systems at different times to perform tasks within the
same application area provides a very popular question.
3. Describe what is meant by
(i) a Management Information System
(ii) a knowledge-based system. (4)
A.(i) -An MIS is software that allows a manager to access..
-and analyse data.
(ii) -A knowledge-based system is one that has all human knowledge on a restricted topic
in the knowledge base..
-together with a number of rules for applying that knowledge..
-and an inference engine used to search the knowledge base.
Notes: A very definition based question. The only other type of question that would be
asked is one that asks for advantages and disadvantages of use of one of these systems in
comparison with some other method of determining information.