Types of System Implementation AND Maintenance PDF

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TYPES OF SYSTEM IMPLEMENTATION AND MAINTENANCE What is Systems Implementation? Systems implementation is the construction of the new system and the delivery of that system into production (that is, the day-to-day business or organization operation). There are a new of ways of implementing a new system. i.

Direct Changeover

ii.

Parallel Running

iii.

Phased Implementation

iv.

Pilot Running

i.

Direct Changeover

ii.

Direct changeover is also referred to as abrupt cut-over installation. Direct installation is whereby the old system is turned off and the new system as shown below. The old system is terminated and the new system will take over. This approach is a high risk approach because there may still be major problems that won’t be uncovered until the system has been in operation. An errors resulting from the new system will have a direct impact on the users and how they do their jobs is depends on the new system. If the system fails to be used on that specific date, delay may occur until the errors are solved.. Although it’s known as risky approach, but it may reduce the cost of installation.

Current System Install New System New System

Time

Direct Installation

Figure 12-2: Direct Changeover

Advantages. 

Takes the minimal time and effort.



The new system is up and running immediately.

Disadvantages  iii.

If the new system fails, there is no back-up system, data can be lost

Parallel Running Parallel installation is when both system; old and new system are operating at the same time until the management decide that the old system can be turned off .This approach is known as riskless approach because all major problems have been solved before the old system is turned off. This approach is an opposite approach with direct installation. Although it’s riskless, but it required high costs since the organization needs to run two systems at the same time. Running two similar systems at one time can be very expensive not only in paying the employee salaries, but also in terms of maintenance. Sometimes, users are also confused since they must deal with two systems

Advantages. 

If anything goes wrong with the new system, the old system will act as a back-up.



The outputs from the old and new systems can be compared to check that the new system is running correctly

Disadvantages. 

iv.

Entering data into two systems, and running two systems together, takes a lot of extra time and effort.

Phased Implementation

The new system is introduced in phases (stages, or steps), gradually replacing parts of the old system until eventually, the new system is fully implemented

/ Advantages... 

Allows users to gradually get used to the new system



Staff training can be done in stages

Disadvantages...  v.

If a part of the new system fails, there is no back-up system, so data can be lost

Pilot Running

The new system is first of all piloted (trialled) in one part of the business / organisation (e.g. in just one office, or in just one department). If the pilot system runs successfully, the new system is introduced to the entire system business / organization.

Advantages. 

All features of the new system can be fully tested.



If something goes wrong with the new system, only a small part of the organisation is affected



The staff that were part of the pilot scheme can help train other staff.

Disadvantages... 

For the office / department doing the pilot, there is no back-up system if things go wrong

REASONS FOR MAINTAINING INFORMATION SYSTEMS What is Maintenance? Maintenance refers to changes made to a system to fix or enhance its functionality. Maintenance is the longest phase in the SDLC. It has Four major activities:  Obtaining maintenance requests  Transforming requests into changes  Designing changes  Implementing changes Many organizations allocate eighty percent of information systems budget to maintenance Maintenance work is often viewed negatively by IS personnel. Organizations have historically have rewarded people involved in new development better than maintenance personnel. Organizations often rotate personnel in and out of maintenance roles in order to lessen negative feelings about maintenance

Types of Maintenance

Corrective maintenance - refers to changes made to a system to repair flaws in its design, coding, or implementation. Most corrective maintenance problems surface soon after installation.When corrective maintenance problems surface, they are typically urgent and need to be resolved to continue normal business activities. Corrective maintenance adds little or no value to an organization; it simply focuses on removing defects from an existing system without adding new functionality. But, of all types of maintenance, corrective maintenance accounts for as much as 75% of total maintenance activity.

Adaptive maintenance refers to the changes made to a system to evolve its functionality to changing business needs or technologies.

Adaptive

maintenance adds enhancements to an operational system, such as new features, increased capability, or changes that improve efficiency or maintainability. An adaptive maintenance project is like a mini-SDLC project, and that adaptive maintenance can be even more difficult than new systems development because the enhancements must work within the constraints of

an existing system.

Adaptive maintenance is usually less urgent than

corrective maintenance because business and technical changes typically occur over some period of time.Adaptive maintenance is generally a small part of an organization’s maintenance effort, but does add Value to the organization.

Perfective maintenance refers to changes made to a system to add new features or to improve performance. The objective of perfective maintenance is

to

improve

response

time,

system

efficiency,

reliability,

or

maintainability.During system operation, changes in user activity or data pattern can cause a decline in efficiency, and perfective maintenance might be needed to restore performance. Usually, the perfective maintenance work is initiated by the IT department, while the corrective and adaptive maintenance

work

is

normally

requestedbyusers.

Preventive maintenance refers to changes made to a system to avoid possible future problems. An example of preventive maintenance might be to increase the number of records that a system can process far beyond what is currently needed or to generalize how a system sends report information to a printer so that so that the system can adapt to changes in printer technology.Preventive maintenance is less likely to occur as compared to corrective maintenance.Finally note that over the life of a system, corrective maintenance is most likely to occur after system installation or after major system changes.

This means that adaptive, perfective, and preventive

maintenance activities can lead to corrective maintenance activities if not carefully designed and implemented.

The cost of Maintenance Information systems maintenance costs are a significant expenditure.

For

some organizations, as much as 80% of their information systems budget is allocated to maintenance activities.

Maintenance expenses are usually high when a system is implemented because problems must be detected, investigated, and corrected. Afterward, costs usually remain low and involve

minor adaptive

maintenance.

Eventually, adaptive, perfective, and preventive maintenance activities increase in a dynamic business environment. Near the end of a system’s useful life, maintenance expenses increase rapidly due to adaptive maintenance and a higher level of corrective maintenance....