Section 1.4
Introduction To Computing
1.4 Business Information Systems
There are three basic levels in business:
The Strategic Level
This group includes the founders and/or the directors of the organisation. They
are responsible for long term planning and policy.
The Tactical Level
These are people who are middle management. They are responsible for operations
within a particular department.
The Operational Level
These are the people responsible for the very basic needs of the company. They
produce the final output.
Each level requires a different type of information system (Although some people
in the operational level do not require an information system).
These information systems can be classified as:
- Operational Systems
- Management Information Systems
- Decision Support Systems
- Expert Systems
Operational Systems
Such systems process data generated by day-to-day business transactions.
Examples:
- Accounting Systems
- Invoicing Systems
- Stock Control Systems
- Order Entry Systems
Management Information Systems
These systems often summarise information generated at the operational level to
generate management information.
Example:
Decision Support Systems
These systems are used by senior management in the strategic level.
A decision support system is designed to help someone reach a decision by
summarising all the avaliable relevant information.
The information may come from:
- Internal company records
- Government statistics
- The stock market
Decision support systems usually include:
- Query languages
- Spreadsheet models
- Graphics
Expert Systems
An expert system combines the knowledge of human experts on a given subject
to copy human reasoning. The software follows a set of rules to draw it's
inferences.
Uses of Expert Systems:
- Complex fault diagnosis
- Geological prospecting
- Social security claims
- Medical diagnosis
1.4.2 Processing Techniques
All computers perform tasks in terms of input, output and process. We can break
this understanding further into three categories:
- Real-time processing
- On-line processing
- Batch processing
Real-time Processing
The computer must keep pace with the external operation and produce
almost instantaneous results.
Real-time systems are usually used in:
-
Process Control
This is the control of an industrial process or machinery by
computer.
Examples:
- Nuclear power station
- Chemical engineering
- Life support systems
-
Interactive Processing
Data is processed upon entry and output is produced almost
immediately.
If the user enters all of the data for one transaction and
then it is processed this is known as transaction processing.
Examples:
- Airline reservation system.
- Stock control systems where an invoice is printed
straight away.
On-line Processing
An on-line system is one where the input device is connected to the computer.
The hardware and software must exist so that the information can be accessed and
possibly changed.
Batch Processing
Batch processing involves several steps:
- Source documents (usually handwritten) are received at the centralised
data processing department.
- The source documents are grouped into batches.
- The source documents are keyed in as a batch and held in a transaction
file.
- The transaction file is processed when the computer is not busy with
other processing.
1.4.3 Combined Interactive And Batch Processing
Some banking applications may use a combination of interactive and batch processing.
Example (Using an ATM):
- The customer inserts their card and types in their PIN number and the
amount of cash that they want.
- The ATM computer retrieves the customers record from the banks central
customer file.
- If the customer has enough money then the ATM computer sends the new
balence to the screen and issues the correct amount of cash.
- The new balence is written to the customer file.
- The ATM program then adds the record to the ATM transaction file which
contains a record for every transaction made that day.
- At 2:00am the ATM is closed for a short while whilst its transaction
file is processed, producing a summary of ATM transactions.
1.4.4 Centralised And Distributed Processing
Centralised Processing
In the 1960's when business systems were introduced it was common to have a centralised
data processing department.
The data processing department had:
- A mainframe
- System Analysts
- Programmers
- and operators
All data to be processed would be sent to the data processing department.
Distributed Processing
With the introduction of minicomputers and later, microcomputers, the trend has
been for each department or individual to do their own processing.
