Information Technology Reference
In-Depth Information
Figure 13.12
Old system
New system
Start-Up Approaches
Direct conversion
Old system
New system
Phase-in approach
Old system
Pilot 1
Pilot 2
Pilot 3
Pilot start-up
Old system
New system
Parallel start-up
application on a smaller scale before making the medical records application available to
people around the world.
Parallel start-up
involves running both the old and new systems for a period of time.
The output of the new system is compared closely with the output of the old system, and
any differences are reconciled. When users are comfortable that the new system is working
correctly, the old system is eliminated.
parallel start-up
Running both the old and new
systems for a period of time and
comparing the output of the new
system closely with the output of the
old system; any differences are
reconciled. When users are
comfortable that the new system is
working correctly, the old system is
eliminated.
User Acceptance
Most mainframe computer manufacturers use a formal
user acceptance document
—a formal
agreement the user signs stating that a phase of the installation or the complete system is
approved. This is a legal document that usually removes or reduces the IS vendor's liability
for problems that occur after the user acceptance document has been signed. Because this
document is so important, many companies get legal assistance before they sign the accep-
tance document. Stakeholders can also be involved in acceptance testing to make sure that
the benefits to them are indeed realized.
user acceptance document
A formal agreement signed by the
user that states that a phase of the
installation or the complete system
is approved.
Systems operation
involves all aspects of using the new or modified system in all kinds of
operating conditions. Getting the most out of a new or modified system during its operation
is the most important aspect of systems operations for many organizations. Throughout this
book, we have seen many examples of information systems operating in a variety of settings
and industries. Thus, we will not cover the operation of an information system in detail in
systems operation
Use of a new or modified system.
