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Characteristics of a TPS

"A transaction is an event that generates or modifies data that is eventually stored in an information system. Transaction processing systems meet record keeping and event tracking needs..."

Reference: Board of studies NSW, Stage 6 Information Processes and Technology, Preliminary and HSC Courses (2007, p.44)

Students need to have a clear understanding of both batch processing and real time processing systems and the role and general understanding of data validation. The topics examined are:

Outcomes
General characteristics for any TPS
Elements of batch processing
Elements of real time processing
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Outcomes

This material addresses aspects of the following syllabus outcomes:

A student:

H1.1 applies an understanding of the nature and function of information technologies to a specific practical situation
H1.2 explains and justifies the way in which information systems relate to information processes in a specific context
H2.1 analyses and describes a system in terms of the information processes involved
H2.2 develops solutions for an identified need which address all of the information processes
H3.2 demonstrates ethical practice in the use of information systems, technologies and processes
H4.1 proposes ways in which information systems will meet emerging needs
H5.2 assesses the ethical implications of selecting and using specific resources and tools
H7.1 implements effective management techniques
H7.2 uses methods to thoroughly document the development of individual and/or group projects.

Source: Board of studies NSW, Stage 6 Information Processes and Technology, Preliminary and HSC Courses (2007)

General characteristics for any TPS

The HSC focuses on storing and retrieving but the the other information processes are also important especially those of collecting and analysing. There are four characteristics that all transaction processing systems should have:

Rapid response: Customers should not be made wait a long time. The quicker the response time the happier the customer and the more revenue that can be collected.
Reliability: This information system involves cash. Any mistakes here can have serious consequences for the companies bottom line, customer satisfaction, auditors, the taxation department and the list goes on. I think you get the idea. You really don't want mistakes when it comes to money.
Inflexibility: You don't want people making up their own rules when it comes to money. It must be performed the same way every time. If any step is altered it becomes more likely that a mistake may be made. With computers it must be rigidly adhered to.
Controlled processing: There must be procedures in place to check that everything and everyone is doing the right thing. On the computers end is something called a transaction processing monitor to ensure that everything is right with the TPS but there must also be human controls to ensure that everyone is doing the right thing.

Activity 1

Why does the HSC consider storing and retrieving to be the main processes of a TPS?
In what ways are the processes of collecting and analysing linked to storing and retrieving?
Identify the four main processes (Storing, Retrieving, Collecting Analysing) that any TPS will have and briefly explain why they are important.
Examine individually what would happen if any of these processes were removed.

Elements of batch transaction processing

There are a few simple things to understand with batch transaction processing. Firstly with batch transaction processing all of the transactions are collected to be processed at a later time such as cheques, invoices and bills such as telephone and electricity. There are cost and time saving advantages to batch processing including:

Advantages

Batch transaction processing saves a lot of time and money when organisations have a large number of repetitious data entry tasks to do which can be automated. Banks will process hundreds of thousands of cheques in large bundles which flick through the scanners faster than the eye can see. This is obviously going to save the banks large amounts of money.
These repetitious tasks may actually take an individual a long time to enter all of the data. Automating these tasks also save a large amount of time.

Unfortunately there are several disadvantages as well including:

Disadvantages

All processing will be carried out at a set time. This usually involves a schedule.
There is no way to watch for errors while the processing is taking place but if a problem occurs with the processing of a batch the whole process must be halted and restarted from the beginning of that batch. Because of the difficulties and cost involved if this occurs batches are often divided into many smaller bundles.
The transaction data still needs to be sorted and bundled which can still be expensive.
The data in a batch TPS will never be completely current.
There are time delays between the initial transaction and the actual processing of that transaction.

Activity 2

Briefly describe what a transaction processing system is and give 2 examples?
Explain why a batch transaction system saves time.
In what ways can a batch system sometimes become expensive when problems occur in processing.
Analyse and explain the statement, "The data in a batch TPS will never be completely current."
Do you think the advantages of a batch system outweighs the disadvantages and justify you answer.

Elements of real time transaction processing

Real time transaction processing involves a transaction that is completed immediately. This may involve a payment over the counter or EFTPOS but whatever is used to complete the transaction it is immediately finalised and does not leave processing for a later time. Two examples of real time processing are airline reservations and banking transaction systems.

There are two immediate concerns for a successful real time transaction. They are:

concurrency: This refers to 2 people not being able to change the same data at the same time. Concurrency is important. Imagine you are booking a seat on a plane and more than one person booked the same seat at once. The results would be disastrous. Imagine if an individual were to have $200 in their account and 2 or more institutions were to be withdrawing that same $200 at once. Nobody could ever say with any certainty how much money they had in an account and double bookings would continuously occur.
Atomicity: Atomicity means that all the steps involved in a transaction must be completed successfully. If any one step fails, the entire transaction fails. Atomicity is the cousin of concurrency. In the same way as we spoke of the booking problems if two or more people could book the same seat or same money was being withdrawn by more than one institution atomicity affects things the same way but for different reasons. Imagine if an institution was part way through transferring $500,000 when the power goes off. Was the money withdrawn? Was it deposited? Could the same transaction take place several times? Atomicity means that if the power goes off and transaction was incomplete then nothing happens. The transaction is completely cancelled. Either the entire transaction happens or nothing happens.

As real time transactions occur while the customer is present it is much easier to check the correctness of the data being entered which is called validation and to double check the accuracy of data already stored which is called verification.

Activity 3