IS 341
Business Systems Analysis
Chapter 10 - Notes
Systems Implementation and Operation
I. Systems Implementation and Operation the
most expensive and time-consuming phase of the SDLC expensive because so many
people are involved, time-consuming because of the work that must be completed
throughout the lifetime of the system;
the seven major activities of this phase fall into three groups:
1. Activities that lead to the system going into
operation
1. Coding turning physical design specifications
into working computer code
2. Testing must be planned early in the
process to decide what needs to be tested and to gather test data
3. Installation actually replacing the old
system with the new one; 4 methodologies:
2. Activities necessary for successful system
operation
4. Documentation for both developers and users
5. Training users need training in the use and
operation of a system;
6. Support where to go for help: online (automated) or to a real person (help
desk)
3. Ongoing activities to keep the system working
and up-to-date
7. Maintenance from the moment it is implemented,
a system will need maintenance for errors, modifications (changing business
needs and changing business environment), and requests for enhancements (new
capabilities)
A.
The Process of Coding, Testing, and Installation (see above)
B.
Deliverables and Outcomes from Coding, Testing, and Installation
1. Coding Code and program
documentation
2. Testing Test plan and test data, Results of
testing
3. Installation User guides, User training
plan, Installation and conversion plan
C.
The Process of Documenting the System, Training Users, and Supporting
Users two groups of people will use the documentation: systems personnel who maintain the system and
users who work with the system; documentation is important to both groups
D.
Deliverables and Outcomes from Documenting the System, Training Users,
and Supporting Users
1. Documentation System documentation and user
documentation
2. Training Classes and tutorials
E.
The Process of Maintaining Information Systems four major activities:
1. Obtaining maintenance requests should be a
formal process , done in writing with signatures on documents
2. Transforming (translating) request into
changes understand (sometimes decipher) what the user actually wants (not
necessarily what he actually asked for)
3. Designing changes a mirror (sort of
) of
the SDLC, planning just what is to be done
4. Implementing changes put the changes into
effect, training, and documentation
F.
Deliverables and Outcomes from Maintaining Information Systems
development of new versions of specific parts of the system, along with new
documentation, training, etc.
II. Software Application Testing testing starts
early in the SDLC process and continues throughout the SDLC; some firms have
special groups whose responsibility is Testing
A.
Seven Different Types of Testing (see Table 10-3, p. 369)
1. Manual
a. Inspections physically looking at the code
for errors, usually subtle errors not picked up by automated checks
b. Walkthroughs formal review of the code by
one or more persons along with the coder
c. Desk Checking executing the program code
one step at a time (manually ) by a reviewer
2. Automated
a. tests for specific errors in code grammar
b. Unit (Module) Testing test the modules
individually for errors
c. Integration Testing bring the modules
together for testing as a whole
d. System Testing bring together the entre set
of programs to see if they work together as a whole
B.
The Testing Process testing is not haphazard or a last-minute thought
before cutover; it must be planned and executed carefully to be effective
C.
Acceptance Testing by Users users test a completed system and give
their acceptance of it
1. Alpha Testing testing a system with
simulated data
2. Beta Testing testing a system with real
data in the real world
a. Recovery Testing for the system to fail to
verify that recovery operates properly
b. Security Testing verify that protection
mechanisms work properly
c. Stress Testing try to break the system;
what happens when the unexpected occurs?
d. Performance Testing determine how the
system operates across a range of environments or conditions; often looking for
response times or other performance measurements
III. Installation the process of changing over
form the current system to the new one;
***SEE TABLE 10-4, p. 375***
1. Direct Cutover completely remove old system
and install entire new system at one time; fast, inexpensive (if done well),
but the most dangerous method
2. Phased (Modular) Cutover install the new
system one part (module) at a time, test it with the users, and when they are
happy install the next component; longest method (time consuming), but works
well with the users (they approve each module, one at a time)
3. Pilot Cutover install the new system for a
select group of users, and when they are satisfied, install the system for
everyone; this works well IF you choose the select group carefully
4. Parallel Cutover run both old and new
systems in parallel for a time to be sure the new systems outputs are correct,
and the old system is still there if its needed; this is the safest method,
but the most expensive (need two full sets of resources to run both systems all
the time)
Planning Installation installations
need to be planned, not just done in the course of the SDLC;
***** 5Ps: Prior Planning Prevents Poor Performance *****
IV. Documenting the System
A.
User Documentation users need to have an explanation on hand to learn
and understand how to use the system
1. System Documentation specifications about
the system
2. Internal Documentation system documentation
that is part of the source code
3. External Documentation includes the outcome
of all the structured diagramming for the system
4. User Documentation written or visual
information specifically prepared for users
B.
Preparing User Documentation
V. Training and Supporting Users
A.
Training Information System Users users need to be trained in the
workings and use of a new system
B.
Supporting Information System Users users will need ongoing education
an problem-solving assistance
1. Automating Support - online
2. Providing Support through a Help Desk a
contact point with a real person
C.
Support issues for the Analyst to Consider recover and backup,
disaster recovery, PC maintenance
VI. Why Implementation Sometimes Fails
sometimes a system just does not work (or work well), and sometimes user do not
like the system in spite of the fact that it works (low user satisfaction)
Stuff Happens! Thats life, get used to
it!
A.
Risk User Involvement
can lower risk, but it adds to time and costs
B.
Commitment to the project the problem should be well understood and
the solution should be approved at high levels in the firm Top Management Commitment!
C.
Commitment to change are persons involved willing and able to change
behaviors, procedures, etc?
Organizational (Cultural) change can ONLY start at the top and must be
personally supported at that level
D.
Extensive project definition and planning the more planning that is
done, the less likely failure
E.
Realistic user expectations Users must be managed! The more realistic their expectations early
in the project, the more satisfaction they will have at the end
VII. Project Closedown project review, team
member reviews, close the contract (customer must sign off), a system audit
(maybe)
VIII. Conducting Systems Maintenance fixes and
enhancements to the system
A.
Types of Maintenance
1. Corrective Maintenance fix mistakes
2. Adaptive Maintenance change functionality
or evolve to changing business needs (environment)
3. Perfective Maintenance add new features or
improve performance
4. Preventive Maintenance avoid future
problems (prepare for Y2K)
B.
The Cost of Maintenance VERY Significant Cost!!!! Up from 50% 9years
ago) to 80% in some organizations (aging systems, too expensive to replace,
cost cuts); Environmental Changes more and faster; get used to it!
1.
Latent defects unknown errors in the system; most maintenance costs
are here (corrective maintenance)
2.
Number of customers for a system the more users, the more maintenance
and training
3.
Quality of system documentation good documentation makes maintenance
easier
4.
Maintenance Personnel maintenance is more difficult than development
(and not as much fun)
5.
Tools CASE tools that can generate code, documentation, etc. can save
a lot of time and costs
6.
Well-structured programs well-designed programs are easier to
understand, fix, and enhance
C.
Measuring Maintenance Effectiveness
1. Number of failures
2. Time between failures
3. Type of failure
D.
Controlling Maintenance Requests which requests are met and which are
declined? Which are critical and which
are wishful thinking?
Errors MUST be fixed! Some are more critical than others
E.
Configuration Management the process of assuring that only authorized
changes are made to the system
1. Baseline Modules software modules that have
been tested and approved to be included in the most recent version of the
system
2. System Librarian person responsible for
checking out and checking in baseline modules (to approved persons for
modification, and from persons who made approved changes; also making sure the
code has been tested and passed the tests before check-in)
3. Build Routines guidelines for constructing
the system
F.
Role of CASE and Automated Development Tools in Maintenance in a
nutshell: to speed development, reduce
errors, and reduce costs
G.
Web Site Maintenance
IX. Maintaining an Information Systems at Pine
Valley Furnitures
X. Electronic Commerce Application: Systems Implementation and Operation
Systems Implementation and Operation
for Pine Valley Furnitures WebStore
1. Developing Test Cases for the WebStore
2. Bug Tracking and System Evolution
3. Alpha and Beta Testing the WebStore