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9.4 Legacy system management 253

High Business Value High Business Value
Low Quality
High Quality
9
10 8
6 7
Business Value Low Business Value Low Business Value

High Quality
Low Quality

1 2 3 4 5

Figure 9.13 An
example of a legacy
system assessment System Quality

Naturally, these options are not exclusive. When a system is composed of several
programs, different options may be applied to each program.
When you are assessing a legacy system, you have to look at it from a business
perspective and a technical perspective (Warren, 1998). From a business perspective,
you have to decide whether or not the business really needs the system. From a tech-
nical perspective, you have to assess the quality of the application software and the
system’s support software and hardware. You then use a combination of the business
value and the system quality to inform your decision on what to do with the legacy
system.
For example, assume that an organization has 10 legacy systems. You should
assess the quality and the business value of each of these systems. You may then cre-
ate a chart showing relative business value and system quality. This is shown in
Figure 9.13.
From Figure 9.13, you can see that there are four clusters of systems:

1. Low quality, low business value Keeping these systems in operation will be
expensive and the rate of the return to the business will be fairly small. These
systems should be scrapped.
2. Low quality, high business value These systems are making an important busi-
ness contribution so they cannot be scrapped. However, their low quality means
that it is expensive to maintain them. These systems should be reengineered to
improve their quality. They may be replaced, if a suitable off-the-shelf system is
available.
3. High quality, low business value These are systems that don’t contribute much
to the business but which may not be very expensive to maintain. It is not worth
replacing these systems so normal system maintenance may be continued if
expensive changes are not required and the system hardware remains in use.
If expensive changes become necessary, the software should be scrapped.