ELECTRONIC DATA PROCESSING MODES

Data processing modes describe the ways in which a computer, under the influence of an operating system, is designed to handle data or transactions during processing.

Types of electronic data processing modes

  1. Batch processing (also referred to asSequentialor Offline processing)
  • Online processing
  • Real-time processing
  • Time-sharing
  • Multi-programming (also referred to as Multi-tasking)
  • Multi-processing.
  • Distributed processing
  • Interactive processing

Review questions

  1. Define the term “Data processing modes”.
  2. Mention five types of electronic data processing modes.

Batch processing

In batch processing, data or transactions are collected & accumulated together over a specified period of time, e.g., daily, weekly, or monthly.  The data is then input & processed at once (or as a single unit) to produce a batch of output.

For example:

In a payroll processing system, details of employees such as number of hours worked, rate of pay, may be collected for a period of 1 month, after which they are used to process the payment for the duration worked.

Data collection is usually done off-line (i.e. away from the CPU) on special machines known as Data entry terminals.  The data is entered & stored on a disk in a batch queue for a while.  It is then input & processed one or more at a time under the control of the Batch operating system, and the result obtained.

Batches of transactions are scheduled for processing by assigning them priorities.  The priorities are assigned in terms of percentage ratio, e.g. 95%, 60%, etc.  The most priority jobs are processed first, while the less priority jobs are processed once the computer resources (i.e., CPU time, Memory & I/O devices) are released by the most priority jobs. 

Once the processing of a given batch starts, there is no interaction between the operator & the CPU.  Therefore, the user cannot intervene to perform amendments to the program. 

A job is not processed until it is fully input.  In addition, a program must wait its turn before processing the data.  This means that, there will be a delay in obtaining results.  For instance, a job may wait in the batch queue for minutes or hours depending on the workload.  Hence, Batch processing cannot be used when the results are needed immediately.

Characteristics/ Features of Batch processing system.

  • The input device does not necessarily need to be connected to the computer.

If the device used for data entry is not connected to the computer, it is said to be Off-Line (away from the computer).

  • The data is not immediately input into the computer, and it is not even immediately recorded in a machine-readable form.
  • The speed of processing is not important. This implies that, processing of the data is done at whatever time is most convenient.

Application areas for Batch processing systems.

Batch processing is commonly applied in:

  1. Payroll systems. 

The attendance data of each employee is collected regularly.  It is then input weekly or monthly as per the demands of the system, processed, & then the pay figures for each employee is obtained.

  • Printing systems (to print documents)

Advantages of Batch processing.

  1. Batch systems are easy to develop.
  2. Processing of data in batches is efficient & economical.
  3. The cost of processing per unit is low.
  4. Batching provides manageable units for control purposes.
  5. Timing of the information (reports) is not a necessity.

Disadvantages of Batch processing.

  1. There are delays in obtaining information.
  2. It leads to overloading of the processing facilities.
  3. Late information is not suitable in situations where instant decisions are required.
  4. It is difficult to provide the scheduling of the desired priority.

Review questions

  1. Briefly explain Batch processing.
  2. Describe the application, advantages and disadvantages of batch processing.

Online processing

In online processing, data or the input transactions are processed immediately they are received to produce the information required.

Online processing occurs when the transactions are processed to update (or make any change in) a computer file immediately after the transactions occur.

In online processing, all the Input/Output facilities, and communication equipments are under direct influence of the central Processor. 

In online processing, the operator communicates directly to the computer’s operating system using commands, which are then interpreted by the supervisor.  This means that, the operator can interact with the system at any point of processing using the Input/Output facilities.

Note.  In online processing, the data input units (terminals) are connected directly to the central computer using communication links. 

In such a configuration, the data (input transactions) are communicated from the workstations to the central computer for processing, & the results communicated back to the workstations through the telecommunication links.

Characteristics of Online processing system.

  • The input device is connected directly to the computer.
  • The input data is processed immediately.  Processing is completed within a short time (usually 1 or 2 minutes), depending on the speed of the system.

Application areas for online processing systems.

  1. Banking:

A bank customer can make an inquiry using an online terminal.  The system would then respond immediately by accessing the relevant file, and inform the customer on the status of his/her account.

  • Stock exchanges:

Terminals located in major stock exchanges throughout the country enables quick processing of shares dealings.

  • Stock control:

Terminals located in warehouses enable stock records to be re-ordered automatically, make reservations, follow-up of outstanding orders, & print picking lists.

  • Manufacturing plants: – to control the progress of work.
  • Inventory status: – i.e., ordering & reporting of geographically dispersed distributors.

Advantages of online processing.

  1. Files are held online; therefore the information generated can be used to update the master files directly.
  2. The Information is readily available for immediate decision-making.
  3. File enquiries are possible at any given time through the terminals (workstations).

Disadvantages of online processing.

  1. Online systems are complex to develop.
  2. They are costly in terms of hardware, software, storage media, operating system, communication facilities, etc.

Review questions

  1. (a). Discuss Online processing. 

(b). Mention and explain the Application, Advantages and disadvantages of Online

processing mode.

Real-time systems.

A Real-time system is capable of processing data so quickly such that the results (output) produced are able to influence, control, or affect the outcome of the activity or process currently taking place.

In a Real-time data processing system, the computer receives & processes the incoming data as soon as it occurs, updates the transaction file, and gives an immediate response that would affect the events as they happen.

The input-originating workstations may be connected directly to the central processor by appropriate communication equipments.  In this case, a transaction is processed & completed immediately or at the same time it occurs.  It also ensures quick update to the affected files (records).

The main purpose of a real-time processing is to provide accurate, up-to-date information, hence; better services based on a real situation.

Requirements of a real-time processing system.

  1. There must be a direct connection between Input/Output devices & the central Processor.
  2. The Response time should be fairly fast, to allow a 2-way communication (interaction) between the user & central processor.

Characteristics/ features of real-time data processing.

  • Provides immediate response on receipt of a message, e.g., enquiries may be answered immediately.
    • The system can respond very quickly to a change of circumstances and initiate a feedback. 
    • They have complex & expensive Operating systems, and usually involve Multi-processing (use of 2 or more processors) to share the workload.                         
    • Real-time systems must be fast and reliable.
    • Real-time systems are dedicated to one type of application.

Application areas for real-time systems.

Real-time systems can be used in applications that require:

  • Quick response.
  • A much short time cycle before the information is available to effect the functioning of its environment.

Examples:

  1. Airline reservation systems:

An individual cannot be booked before enquiring whether the airline seat is available.  The customer may request for an airline booking information through a remote terminal and the requested information will be given out immediately by the reservation system.  If a booking is made, the system immediately updates the reservations file to avoid double-booking, and sends the response back to the customer immediately.

This implies that, before the next transaction can be processed, the files must have been updated by the previous transactions.

  • Theatre (cinema) booking.
  • Hotel reservations.
  • Banking systems for making enquiries about customers’ accounts.
  • Police enquiry systems.
  • Chemical processing plants:

If the temperature is to be regulated, then a rise in temperature requires immediate reaction for correction to restore it to an equilibrium state.

  • In Missile control systems
  • In Hospitals – to monitor the progress of a patient.

Advantages of real time systems.

  1. The information is readily available for instant decision-making.
  2. Provides better services to users or customers.
  3. It is a fast & reliable mode of data processing.
  4. Validation of data can be done instantly.
  5. Reduces circulation of hardcopies.
  6. Provides up-to-date information.

Disadvantages of real-time systems.

  1. Real-time systems are very expensive & require complex Operating systems.
  2. The systems are not easy to develop.
  3. They require large communication equipments, e.g., they require a Front End Processor (FEP), which is used to relieve the central computer by handling some of the limited processing activities, and also link the terminals to the central computer.
  • Real-time systems use 2 or more computer processors sharing up the workloads, which are expensive.

Review questions

  1. (a). Name two industries that extensively use Real-time processing.

(b). Name 3 advantages of a Real-time system.