2.5 Manipulation and/or Processing

In this section you must be able to:

• Describe the different modes of operation: batch, interactive, transaction and real-time, identifying appropriate contexts for use.

• Describe the characteristics of processing data in the form of text, pictures, numbers and sound.

Processing Data• As a home user of ICT you don’t have a great

amount of processing to do

• A large organisation, however, may have millions of transactions a day that need processing

• A transaction is an event in the organisation that needs to be recorded to keep track of its goods and services. Examples include:– Ticket sales – they need to be recorded so they are

not over-sold

– Hire companies, libraries, etc. will need to track their property by recording the loans

– Banking – paying in or withdrawing money

– Recording attendance – e.g. clocking in at factories or taking the register in classrooms

Transaction Processing• These transactions are used to update the

state of the business, or the records of people or items within the business

• For example, if you pay £1000 into the bank, you would hope that your balance would increase by £1000

• Some transactions need to be processed immediately, some can wait until the end of the day, and some can even wait months

• There are different modes of processing that can be used to process transactions

Master Files and Transaction Files• The state of an organisation, or of the customers,

goods or services within an organisation are stored in master files

• Events occurring within the organisation are recorded in transaction files

• Many of these transactions will require the master file to be updated. For example, in a bank, the following transactions will require the customer’s record to be updated:– A change in the customer details – e.g. if they move house

– A customer closing an account

– Someone cashing a cheque written by the customer

– The customer making a deposit

– The customer withdrawing money through an ATM

Modes of ProcessingModes of processing include:

• Batch processing

• Real-time processing

• Pseudo real-time processing

You might also hear the terms:

• On-line processing

• Interactive processing

• Transaction processing

Although these are not clearly defined!

MasterTransaction

UpdatedMaster

Process

Batch Processing• Some transactions don’t require an immediate

response - all the transactions can be collected and processed together; this is called batch processing

• Payroll systems, for example, only need to pay people monthly, and all the processing can be done at once at the end of month.

• Financial institutions might only update balances at the end of the business day

• Utility companies only need to process meter readings every month or every quarter to produce the bills

• Batch processing is usually done on a regular basis, e.g. daily, weekly, monthly, etc.

Stages in Batch Processing• Transactions are gathered together in batches

– they may be keyed in from paper records, or collected electronically from input devices

• Manually entered data will be keyed in off-line, verified and validated, and stored in a transaction file

• Transactions may be sorted into the same order as records in the master file to facilitate processing

• Processing begins – possibly at a pre-determined time, e.g. overnight

• There is no user intervention

• The master file is updated

Interactive Processing• Not all systems or changes will require a

transaction file to be created

• For example, if you phone up your insurance company and tell them that you’ve got a new car, they can update your record while you’re on the phone

• Systems in which data are entered and processed straight away are called interactive

• Interactive systems have a dialogue with the user – e.g. they respond to input and produce an output

• Some systems use a mixture of modes – e.g. you can ask for your balance from a cash machine (an interactive process), but if you make a withdrawal your balance gets updated overnight (a batch process)

Real-time Processing

• With real-time processing, the system responds instantly to inputs or events as they occur

• An example might be a car engine management system – when you press the accelerator the engine reacts instantly; it doesn’t store the information and update the engine speed overnight!

• Business systems tend to react more slowly – if you’re booking a plane ticket on-line then a delay of a few seconds is acceptable; this is know as pseudo real-time processing

Choosing a Processing Mode• How do you decide on whether your system

should use batch or real-time processing?

• You need to consider:– Whether the information from the system needs to

be up-to-date at all times, or whether it’s enough to be updated at regular intervals

– The scale of the operation – batch processing is usually used with high volumes of data

– Cost – real-time systems will require faster communication links and more elaborate backups and procedures to deal with errors and breakdowns

– Patterns of computer usage – batch processing often uses spare computer capacity, e.g. by doing the processing overnight or at weekends when the computer would otherwise be idle