Ch 26

1. Ch 26

2. Objectives • You should understand the differences between batch processing, online processing and real-time processing, including: • Billing systems • Booking systems • Payment systems • Real-time systems

3. Types of processing • There are three basic types of processing: • Batch processing • Online processing • This is sometimes known as transaction processing • Real time process control

4. Batch processing With Batch Processing, a number of jobs are collected together over a period of time They are loaded onto a computer system (in a job queue) And then processed all at once (in a batch)

5. Once the batch processing starts, there is no need for any human intervention at all • It can only be done where there are no timing constraints (ie no response is needed from the computer right away)

6. Batch Processing Examples of batch processing are: the processing of bank cheques payroll non-automatic stock control systems utility billing

7. Batch Processing : Advantages • Can be performed at night when the computer system is not so busy • People do not need to be involved

8. Batch Processing : Disadvantages • Data is only up to date only when the batch processing has finished • Cannot produce adhoc reports

9. Online processing Data is entered by the user, and the computer processes the data straight away. Processing done as quickly as possible; booking of airline ticket or cinema ticket (these need to be marked as “sold” or “unavailable” immediately the booking is confirmed). • Sometimes called interactive processing • File is updated as each transaction is processed eg ATM, flight booking etc

10. Online Processing : advantages and disadvantages

11. Examples of Online processing • Flight bookings • Cinema bookings • Theatre bookings • ATM withdrawals

12. How an online booking system works Online booking systems rely on the ability to update files immediately, in order to prevent double-booking of seats etc There are a number of steps involved: the order of these is important

13. Online booking: steps 1 • Customer logs on to theatre website and clicks on required performance • Enter date & time + number of seats • Seating display: choose seats • If seats are available, seat numbers and price are displayed • Customer clicks ‘confirm’ • Seats are now set temporarily in the theatre database as ‘unavailable’

14. Online booking: steps 2 • Customer enters personal details (eg username & password • Select payment method & make payment • EFTPOS system contacts customer’s bank and enquires if funds are available • Payment is confirmed • Reference number onscreen/email • Database updated with the transaction

15. Real time Process Control The computer responds instantly to events occurring. E.g. Flight simulator Usually involves sensors and feedback loops Real time mode is used in computers that have to react very quickly to inputs requiring immediate outputs (e.g. aircraft ‘fly-by-wire’ controls).

16. Real time Process Control (advantages and disadvantages)

17. Real Time Processing Examples of real-time processing are any control system which uses sensors requiring immediate response e.g. Rockets fired onto space Robots Computer controlled air conditioning / Central heating / burglar alarm Computer controlled greenhouses etc.

18. Examples of processing types

19. Criteria for choosing processing methods Things to consider when choosing a processing method: Whether information needs to be up to date at all times Scale of the operation: Batch systems suited to processing of huge amounts of data Cost: Real time system more expensive; more complex backup and recovery procedures required Computer usage: Adv of batch, can process overnight on mainframe computers