System development life cycle

1. Analysis
 Investigation
 Information Sources
 Feasibility
 Requirements
2. System Design / Development
3. Implementation
4. Maintenance and Support
2Information Systems lhei

it determines whether or not there is a need to
establish the system
its most important output is to determine and
document the existing business process using various
information sources, that gives you an idea on how
business processes can be improved

serve as a basis for analysis of the systems
 Interviews – interviewing the personnel working in the
system to know about the problems or difficulties they
encounter, the managers to determine the
requirements of the system, and the supposed users to
determine their membership in the existing system.
 Documentation – for existing systems, it gives
information as to what data people use, how it serves
the organization and how information is manipulated.

 Observation – to determine closely how a system
operates, an analyst should go to the site or the
workplace and observe it for a certain period. The analyst
can use DFD or ERD to aid in the analysis. These
diagrams show the flow of information in the different
subsystems of the organization, which then reveals the
problem areas or sources.
 Questionnaires – these are used to gather information
when an interview is impractical like in dispersed areas of
operations. However, questions should be made in such a
way that reliable information could be gathered from the
respondents. 5Information Systems lhei

determining the feasibility is the analyst’s objective
in studying the systems before implementation.
 Technical feasibility – refers to the availability of the needed
hardware, software and telecommunications equipment.
Inavailability of equipment means additional cost to the
organization
 Economic feasibility – means that the benefits would
outweight the costs in establishing and maintaining the
system
 Operational feasibility – means that the system, at least
theoretically, would work in the organization

these are the essential features and functions that
the system is expected to fulfill
these are what the system should be able to do and
the means by which it will fulfill its stated goals

 its primary purpose is to ascertain the means
to meet the system requirements identified
in the list of requirements
 the design phase entails assessment of the
supposed solutions to a problem and the
identification of the hardware, software and
telecommunications equipment necessary to
bring about these solutions. It has four steps:

1. Logical Design
2. Physical Design
3. Development or Construction
4. Testing

 the user requirements in the analysis phase are
converted into detailed functions of the system.
Designers should determine the following during this
phase:
▪ Input files – the files that will be used to capture the
input data
▪ Procedures – the logical algorithms used to process the
input. The procedures will later be transformed into
code written in a programming language.

 Designers should determine the following during this phase:
▪ User dialog – the manner in which the user will interact with the system:
windows, menu, icons, and/or provisions for query by example. Usually,
there is heavy emphasis on creating an intuitive, easy to use GUI
▪ Interfaces – how the system will interact with other systems. This
includes provisions for input of data and information from the files of
other systems, retrieval of data from other systems and output of data
to other systems.
 Graphical presentations or analysis and design tools are used to
illustrate the logical operations and document the specifications
of the system. These includes: flowcharts, DFDs, data
dictionaries, decision tables, decision trees, process specification
and structured English (pseudocode)

 refers to the process of specifying the hardware and
software necessary to support the system. The project
team may opt for commercial application software (pre-
developed software that are available for purchase) or
customized software (the team will develop their own
software).

 Programming – to develop the software required
by the system that includes five steps which are:
(1) reviewing the program specification, (2)
designing the program, (3) coding the program,
(4) testing the program, and (5) finalizing the
program documentation

 Equipment acquisition – can be done
simultaneously with programming. It is when
final decisions regarding acquisition are done like
additional specifications. The purchase of
equipment should be based on the list specified
by the systems analyst during the analysis phase.
 Documentation can also be done concurrently with the system
development phase. Program documentation refers to the
compilation of transcribed materials or data and diagrams that are
sometimes already stored in the computer like the procedure
manuals.

 to ensure that the program operates together to
accomplish the desired function.
 it is done by feeding similar data to be processed in the
system to evaluate the current system against the
requirements specified in the analysis phase
 this is to make sure that the requirements are met and
the goals are achieved

 after testing the system and errors, if any, are
corrected, it will then be put into operation so
the people will start using the new system. This
phase has two parts
 Training – to teach people how they will use the new
system
 Conversion – the process of switching from the old
system to the new one.

 SDLC does not end with the implementation of the
system
 maintenance is also a part of the responsibility of the IS
professional
 maintenance may involve monitoring the performance
of the system to check performance measures with
those indicated in the system requirements so that
necessary changes may be employed
 error correction is also part of support to users for it
calls for post implementation debugging or correcting
“bugs” in programs which may cause problems to
users.

System development life cycle

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