A technical requirement pertains to
the technical aspects that your system must fulfill,
such as performance-related issues, reliability issues,
and availability issues. These types of requirements are
often called quality of service (QoS) requirements, service-level requirements or
non-functional requirements (I don't like that term as
it makes them sound like requirements that won't work). Examples of technical requirements are
presented in Figure 1. As you can
see, technical requirements are summarized in a similar
business rules: they have a name and a unique
identifier (my convention is to use the format TR#,
where TR stands for technical requirement). You document
technical requirements in the same manner as business
rules, including a description, an example, a source,
references to related technical requirements, and a
Figure 1. Technical requirements
- TR34 The system shall be available 99.99% of the
time for any 24-hour period.
- TR78 A seminar search will occur within less than
three seconds 95 percent of the time.
- TR79 A seminar search will occur within no more
than ten seconds 99 percent of the time.
I'm a firm believer that you should
minimize the number of purely technical requirements.
Technology changes quickly and often requirements based
on technology change just as quickly. An example of a
pure technical requirement is that an application be
written in Java or must run on the XYZ computer.
Whenever you have a requirement based purely on
technology, try to determine the real underlying
business needs being expressed. To do this, keeping
asking why your application must meet a requirement. For
example, when asked why your application must be written
in Java, the reply was it has to run on the Internet.
When asked why it must run on the Internet, the reply
was your organization wants to take orders for its
products and services on the Internet. The real
requirement is to sell things to consumers at their
convenience; one technical solution to this need (and a
good one) is to write that component in Java that can be
accessed via the Internet. A big difference exists
between having to write the entire application in Java
and having to support the sales of some products and
services to consumers over the Internet.
Many technical requirements can
actually be thought of as
constraints, and in fact constraints can apply to
either technical or
This artifact description is excerpted from Chapter 7 of
The Object Primer 3rd Edition: Agile Model Driven
Development with UML 2.