Chapter 8 • Basic Systems Concepts and Tools 331
Component
1
Component
2
Component
3
Interface
Interface
System
Interface
Output 1
Input 2
Input 1
Boundary
Environment
Storage
1
FIGURE 8.2 General Structure of a System
- BoundaryThe delineation of which elements (such
as components and storage) are within the system
being analyzed and which are outside; it is assumed
that elements within the boundary are more easily
changed and controlled than those outside.
- EnvironmentEverything outside the system; the
environment provides assumptions, constraints, and
inputs to the system.
- InputsThe resources (i.e., data, materials, supplies,
energy) from the environment that are consumed and
manipulated within the system.
- OutputsThe resources or products (i.e., informa-
tion, reports, documents, screen displays, materials)
provided to the environment by the activities within
the system.
- ComponentsThe activities or processes within the
system that transform inputs into intermediate forms
or that generate system outputs; components may
also be considered systems themselves, in which
case they are called subsystems, or modules.
- InterfacesThe place where two components or the
system and its environment meet or interact; systems
often need special subcomponents at interfaces to
filter, translate, store, and correct whatever flows
through the interface.
- StorageHolding areas used for the temporary and
permanent storage of information, energy, materials,
and so on; storage provides a buffer between system
components to allow them to work at different
rates or at different times and to allow different
components to share the same data resources.
Storage is especially important in IS because data
are not consumed with usage; the organization of
storage is crucial to handle the potentially large
volume of data maintained there.
Figure 8.2 graphically illustrates how these seven elements
interrelate in a system.
These elements can also be used to describe specific
computer applications. For example, in Figure 8.3 a
payroll application and a sales-tracking application are
described in terms of five system elements, excluding
boundary and environment.
Another important system characteristic is the
difference between formal versus informal systems
within organizational contexts. The formal system is the
way an organization was designed to work. When there are
flaws in the formal system, or when the formal system has
not been adapted to changes in business situations, an
informal system develops.
Recognizing that an organization’s formal system is
not necessarily equivalent to the real system is crucial when
analyzing a business situation or process. For example, if
workers continue to reference a bill-of-materials list that
contains handwritten changes rather than a computer-printed
list for a new shop order, an informal system has replaced
the formal information system. In this case, the real system
is actually the informal system or some combination of the
formal and informal systems.
