Topic 7 - section 3

Topic 7 - section 3

1. Types of processing

   • Batch - at a later time
     • Batch processing is used when there are a large number of similar transactions to be processed
     • All data to be processed is collected together in a single operation before being processed
     • Main features
       • No human intervention during the processing once the data has been entered the processing takes place automatically
       • Processing is delayed until a convenient time
       • There is a delay in processing which mean the master file may not be up-to-date
       • Data is processed in large groups and all at the same time
       • Control, hash and batch totals are used to ensure that all data has been entered correctly
   • Transaction - short delay
     • Transactions are processed when they arise
     • The short delay is because the system must complete each transaction before starting the next one
     • E.g
       • A flight being booked
       • Withdrawing money from an ATM
     • Features
       • It is interactive there is a constant interaction between the user and the computer
       • A transaction is dealt with as soon as it occurs, transactions are completed almost immediately
       • Each transaction is completed before the next one begins
       • They are ideal for booking systems since it will be impossible to book the same seat twice
   • Real time - no delay
     • Is when they system responds instantly to event. There is no delay. The system will responds immediately and alters the exteranl conditions in some way which in turn affects the input
     • The speeds of RTP necessitates a computer devoted just to this type of processing
     • Examples
       • Nuclear power plants where a chemical process is controlled by computer using data from sensors which is constantly changing
       • Flight control with automatic flight control or actual control
       • Games - action games where an immediate response is required
   • Interactive processing

2. Choosing a processing mode

   • Many systems applications will use a combination of batch and transaction processing
     • The choice depends on:
       • Whether the data has to be completely up-to-date all the time
       • Cost
         • Real time is expensive
       • Computer usage
         • Batch processing can take advantage of idle computer time e.g over night