Information System (IS) life cycle.pptx

By: Asst. Lec. Afrah Salman Dawood

 System life cycle and the waterfall model.
 The issues that indicate the need for a new
system.
 Overview of main stages.
 Methods of conversion.
 Post-implementation review.
 System maintenance.

 Information System (IS) is a collection of
components that work together to provide
information to help in the operations and
management of an organization.
 Information Technology (IT) is the integration
of computers, communications equipment, and
other technology used in information systems.

 System life cycle (SLC) is an
organizational process of
developing and maintaining
systems. It helps in establishing a
system project plan, because it
gives overall list of processes and
sub-processes required for
developing a system.
 Software development life cycle
(SDLC) models show the ways to
navigate through the complex and
demanding process of software
building. A project’s quality,
timeframes, budget, and ability to
meet the stakeholders’
expectations largely depend on the
chosen model.

 Through all development stages, the process
moves in a cascade mode. Each stage has concrete
deliverables and is strictly documented. The next
stage cannot start before the previous one is fully
completed.

 Requirements are very well known.
 Product definition is stable.
 Technology is understood.
 New version of an existing product.
 Suitable for small size projects.
 Constant testing of the design is needed.
 Helps to find errors earlier.
 Easy to understand, easy to use.
 Testing is done at every stage.

 Time consuming documentation workflow.
 Poor integration.
 Monitoring and alerts for medical coding.
 Poor mobile access and communication.
 The discovery of the need for a new system or
enhancement to an existing system.

 Stage 1: Analysis
Activities/processes that are carried out in this stage are:
o Problem statement - A report that highlights any potential issues that
could occur during the analysis and design of the systems.
o Interview with the users - The interviews are held with the users to
determine whether they are willing to use the systems, are they
experienced enough or would they need training etc.
o Feasibility study - The people conducting the analysis look at the
possibility of the project that they are working on. For example, checking
the resources that are available to them (is the budget big enough?, do they
have enough staff/time?)
 Stage 2: Design
o Process description - Accurate and detailed explanations of every process
that is going to be occurring in the new system. For example, database
software that will be used for keeping records.
o Data flow diagrams - These provide a visual representation of the data
flow travelling through a system. This allows a user to get a much better
understanding on the processes that occur in a system.
o Data dictionary - Is a set of information that describes the content,
functions and structure of a system.

 Stage 3: Implementation
o Program coding - In this stage, the actual installation of the system begins.
The actual coding of programs/applications will take place, using assets
that have already been produced (data dictionary, data flow diagrams etc.)
o Migration of data - Means to transfer all the information from the original
system over to the one that is being put in place.
o Training the users - Once this has all been done, the users would need
sufficient training in how to use these systems, based on the interviews that
were held earlier on the amount of time needed to train them may vary
depending on how inexperienced the users are with these systems.
 Stage 4: Testing
o Data testing - Refers to the testing of the information stored on the system
(for example, programs that have been installed onto the system, do they
work? Is it suitable for the user to use? Has all the data been transferred to
the new system? Etc.)
o Compatibility checks - Are done to make sure that all the
information/programs/applications that have been installed onto the
system can work properly on said system. As well as tests to make sure that
the user is able to work with the system (is it user friendly? Are there any
bugs in the system preventing them from being able to use it? Etc.)
o Verification - The system has to be verified that is 100% functional, is safe
for users to begin using, can support all the desired information etc.

 Stage 5: Evaluation
o Reviews - Once the system has been fully set up and
declared available for use, a review/reviews need to be
conducted in order to reflect on how the design and
analysis of the system went. Was the budget big enough to
support the project? Were there enough resources? Did we
meet all the goals for the project? How closely were the
steps of the development life cycle followed?
o Performance monitoring - The performance of the system
will then be monitored for a period of time after the user
has began to work with it. This is to make sure that they
have received sufficient training in the use of the system,
as well as to check if any issues/errors crop up after the
initial setup has taken place.
o Amendments - If there are any problems detected in the
performance monitoring, amendments will need to be
done in order to make sure that these issues are fixed and
are unlikely to occur again. Think of it as regular updates
being applied to the system.

 System Conversion is the
process of changing from the
old system to the new one.
 There are four methods of
handling a systems
conversion:
 Parallel conversion
 Direct conversion (also called
“Big Bang”)
 Pilot system (also called
“Single-location installation”)
 Phased conversion

 Parallel conversion
 Under this approach, users continue to operate the old
system in the accustomed manner but they also begin to
use the new system.
 This method is the safest conversion method since it
guarantees that, should problems such as errors in
processing or inability to handle certain types of
transactions arise in using the new system, the
organization can still fall back to the old system without
loss of time or loss of service.
 Direct Conversion
 The direct changeover method converts from the old
system to the new system abruptly, sometimes over a
weekend or even overnight.
 The old system is used until a planned conversion day,
when it is replaced by the new system - there are no
parallel activities.

 Pilot system
 When new systems involve new techniques or drastic
changes, the pilot approach is often preferred.
 In this method, a working version of the system is
implemented in one part of the organization, such as a
single work area or single department.
 The users in this area know that they are piloting a new
system and that changes can still be made to improve the
system.
 Phased conversion
The phased method of conversion introduces the new system
gradually.
 It can be used when it is not possible to install a new
system throughout an organization all at once.
 This may be due to incomplete training of users, late
arrival of equipment or limited funding meaning that the
costs involved in the introduction of the new system need
to be spread over a period of time, ranging from weeks to
months.

 post-implementation review is a process to
evaluate whether the objectives of the project
were met. You can also use it to see how effective
the project was managed. This helps to avoid
making similar mistakes with future projects and
learning how to run the project better.
 It is the last step in your project cycle and usually
involves an independent party, which can act more
objectively in making their determinations about
how the project was run. This provides the
stakeholders of the project the confidence to know
that the objectives of the project were met
successfully.

 The results obtained from the evaluation process
help the organization to determine whether
its information systems are effective and efficient
or otherwise. The process of monitoring,
evaluating, and modifying of existing information
systems to make required or desirable
improvements may be termed as System
Maintenance.
 Four types of maintenance task can be identified
1. Corrective maintenance
2. Adaptive maintenance
3. Perfective maintenance
4. Preventative maintenance

1. Corrective Maintenance: This type of maintenance implies
removing errors in a program, which might have crept in the
system due to faulty design or wrong assumptions. Thus, in
corrective maintenance, processing or performance failures are
repaired.
2. Adaptive Maintenance: In adaptive maintenance, program
functions are changed to enable the information system to
satisfy the information needs of the user. This type of
maintenance may become necessary because of organizational
changes.
3. Perfective Maintenance: Perfective maintenance means adding
new programs or modifying the existing programs to enhance
the performance of the information system. This type of
maintenance undertaken to respond to user’s additional needs
which may be due to the changes within or outside of the
organization. Outside changes are primarily environmental
changes, which may in the absence of system maintenance,
render the information system ineffective and inefficient.
4. Preventive Maintenance: Requires analysis of areas where
trouble is likely to occur, IT department normally initiates
preventative maintenance , often results in increased user
satisfaction, decreased downtime.

Information System (IS) life cycle.pptx

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