Parallel running

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Parallel running is one of the ways to change from an existing system to a new one.[1] This conversion takes place as the technology of the old system is outdated so a new system is needed to be installed to replace the old one. The phrase parallel running can refer to the process of changing a fragment of business information technology operation to a new system or to the technique applied by the human resources departments in which the existing staff stay on board during the transition to a new staff.It is one of the strategies for system implementation [2] in which both the old and new systems are running side by side until the users are certain that the new system has no problems.After a period of time, when the system is proved to be working correctly, the old system will be removed completely and users will depend solely on the new system.

The old and new systems are doing the same processing and operating side by side


Parallel running is a process that is usually adopted when new method is applied to the system. During this process, while the newly applied system works, the old system remains to be worked at the same time. All the data that has applied to the old system should be applied to the new system as well.

During this time, it will proceed a confirmation process to check the function and operation of the new system.[3] Once the new system is proven to be operated well, the old system will be withdrawn.[4]

In addition, it can also be referred to two different applications running at the same time to reach certain output, which usually adopted in supercomputer system.[5]


In business environment, when a new system is applied to the organization, it is hard to predict how the new system will perform with regard to the previous system that already exists. If the new system is carried out without having the old system running simultaneously, there is a possibility that it obstruct the business process once the new system has an error.

However, if both systems are implied, old systems can act as a ‘back up'.[6] By using parallel running process where old system and new system run together, business owners are allowed to have an opportunity to acknowledge how the new method will function without hindering existing business procedure.[7]

Furthermore, the new system can be compared with old system during this period. Therefore, the parallel run period enables the leaders to confirm that the new system is set up rightly and it functions better than the old one, so that it is ready to be carried out.


Despite the benefits of the parallel running, few flaws of the system have been suggested.

As two systems (old and new) are processed together at the same time, it may demand additional works to be done, require more complicated procedure, and more cost.[8] It may also discourage workers as it demands to repeat the same works twice.[9]

In addition, it is hard to run both systems proportionally and users may find the system confusing as it is two different systems running together.[10] Furthermore, it may cause an error followed by an increase in too much input of data. Once an error occurs in one of the systems, it is no longer be able to run parallel, and it may result in waste of time and human efforts to investigate to track down where the error started to fix issue.

Parallel Running system in Generators[edit]

Parallel running system can also be used in Generators, which can be described as one of the systems that supplies electric power. When a certain level of output in the power system is required, each generator may not be able to provide the exact amount of output that corresponds to the required output. (Some may produce more output than the required amount, and some may produce less.) [11] In this case, parallel running system can solve the complication. Also, when the lower output is demanded, it can reach the requirement easily by having one or some generators stop working.

Most preferred way of using parallel running system in generators is to find generators that are capable of produce the same or similar amount of output.[12] Another way is to have two or more generators that have different level of output. Either way, they should be linked in parallel by using switchgear when they are performing to reach the demanded output. The transient quality of power system enable the two different generators to work together for attain the same goal.[13]

Reference List[edit]

  1. ^ Wainwright, Stewart (2009). IGCSE and O level Computer Studies and Information Technology. Cambridge. p. 29. 
  2. ^ Leadbetter, Chris; Blackford, Roger; Piper, Tony (2012). Cambridge International AS and A Level Computing Coursebook. United Kingdom: Cambridge University Press. p. 63. ISBN 978-0-521-18662-9. 
  3. ^ [1], Spence, S. Project Trinity – Parallel Running[online].UK:Project Trinity, no date. [Accessed25October2014].
  4. ^ [2], University of Cambridge, Implementing the New System[online]. UK:IGCSE ICT, no date. [Affessed25October2014].
  5. ^ [3], Nazir, M. Cost-Effective Resource Management for Distributed Computing [online]. UK:University College London, 2011.
  6. ^ [4],, (2014). IGCSE ICT - Implementing the New System. [online].[Accessed 27 Oct. 2014].
  7. ^ [5], wiseGEEK, (2014). What Is Parallel Running?. [online][Accessed 27 Oct. 2014].
  8. ^ [6],, (2014). Developing an Information System - Implementation. [online]. [Accessed 27 Oct. 2014].
  9. ^ [7],, (2014). BBC - GCSE Bitesize: Implementation. [online]. [Accessed 27 Oct. 2014].
  10. ^ [8],, (2014). Advantages and disadvantages of Parallel systems . [online].[Accessed 27 Oct. 2014].
  11. ^ [9],, (2014). Parallel Operation of Generator Sets | Diesel Service. [online]. [Accessed 27 Oct. 2014].
  12. ^ [10], Nitta, T. and Okada, T. (1989). Transient characteristics of parallel running of the 20 kVA superconducting synchronous generator and a conventional one. IEEE Transactions on Magnetics, [online] 25(2), pp.1775-1778.[Accessed 27 Oct. 2014].
  13. ^ [11], AKSApowergeneration, (2014), Parallel Generators and Synchronization, Generator Power, System Design. [online].[Accessed27 Oct. 2014].