1. FatMax 2007. Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 LicenseCreative Commons Attribution-NonCommercial-ShareAlike 2.5 License Modes of Processing

2. FatMax 2007. Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 LicenseCreative Commons Attribution-NonCommercial-ShareAlike 2.5 License Definition - transaction All data processing systems are concerned with transactions – events that need to be recorded Examples could include: Buying a product in a shop Withdrawing cash from an ATM Booking a cinema ticket Navigation control on an aeroplane Using gas/electricity etc.

3. FatMax 2007. Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 LicenseCreative Commons Attribution-NonCommercial-ShareAlike 2.5 License Modes of processing Real-time Transaction Batch Real-time Batch Transaction No delay (i.e. instant) Short delay At a later time Three methods are used to process transactions: The main difference between them is how soon after input data is processed.

4. FatMax 2007. Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 LicenseCreative Commons Attribution-NonCommercial-ShareAlike 2.5 License Batch Processing 1 Batch processing is used when there are a large number of similar transactions to be processed All the data to be processed is collected together BEFORE being processed in a single operation Processing is delayed until a convenient time e.g. at night or weekly or monthly There is a delay in processing which means the master file may not be up-to-date

5. FatMax 2007. Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 LicenseCreative Commons Attribution-NonCommercial-ShareAlike 2.5 License Batch Processing 2 Transactions are batched together in an offline transaction file The transaction file is sorted into the same record order as the master file Records from the transaction file are merged with corresponding records in the master file Updated records are stored in a new master file The cycle is repeated for each record in the transaction file 1 5 4 3 2 The old master file is called the father and the new master file the son. When the son is used to create a new master file it becomes the father and the old father becomes a grandfather. Both the father and grandfather will be stored for backup purposes

6. FatMax 2007. Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 LicenseCreative Commons Attribution-NonCommercial-ShareAlike 2.5 License Batch Processing 3 An example of batch processing is the way that credit card companies process billing. The customer does not receive a bill for each separate credit card purchase but one monthly bill for all of that month’s purchases. The bill is created through batch processing, where all of the data are collected and held until the bill is processed as a batch at the end of the billing cycle.

7. FatMax 2007. Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 LicenseCreative Commons Attribution-NonCommercial-ShareAlike 2.5 License Transaction Processing 1 In transaction processing data is entered and processed “straight away” However, there may be a short delay as the system must COMPLETE each transaction BEFORE starting the next one Sometimes called interactive or pseudo real-time processing i.e. it “looks” like stuff is happening instantly

8. FatMax 2007. Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 LicenseCreative Commons Attribution-NonCommercial-ShareAlike 2.5 License Transaction Processing 2 A common use of interactive processing is for booking systems Remember, each transaction must be completed before the next one begins Why does this make interactive processing the most appropriate method for booking systems?

9. FatMax 2007. Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 LicenseCreative Commons Attribution-NonCommercial-ShareAlike 2.5 License Real-time Processing Real-time processing occurs when the system responds instantly to events Examples include: Controls on an aeroplane Nuclear reactors/power stations Computer games

10. FatMax 2007. Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 LicenseCreative Commons Attribution-NonCommercial-ShareAlike 2.5 License Choosing a processing mode The choice of method will depend on a number of factors: Whether data has to be completely up-to-date at all times Cost – real-time/pseudo real time systems are generally more expensive. Why? Computer usage. Batch processing can take advantage of idle computer time e.g. overnight Many systems applications will use a combination of batch AND interactive processing.

11. FatMax 2007. Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 LicenseCreative Commons Attribution-NonCommercial-ShareAlike 2.5 License Tasks Use your textbook/Internet resources to make notes on “Modes of Processing” Complete the exercise on pages 187 – 188 of Mott & Leeming