Managing Information Technology

334 Part III • Acquiring Information Systems

BufferAllowing two subsystems to work together
without being tightly synchronized, as by having the
interface collect data until the next component is
ready to accept the data
SecurityRejecting unauthorized requests for data
and providing other protection mechanisms
SummarizingCondensing a large volume of input
into aggregate statistics or even mathematical
parameters to reduce the amount of work needed by
subsequent subsystems
Interfaces also can be built between preexisting
independent systems. For example, a company might
contract with an outside organization (possibly a bank) to
process payroll checks or with a market research firm to
capture competitor sales data. In each case, an interface is
built that allows the external system to communicate with
the company’s internal systems. Different formats for data,
different identifications for customers or employees, and
various other differences in definitions and coding need to
be translated to support this type of interface. Sometimes
these interfaces are called bridges because they connect
two “island” systems.
Bridge programs are relatively common. Bridges are
expedient ways to accomplish the goal of expanding the
capabilities of any one system. Rather than take the time to
redesign two systems into one (e.g., to reduce redundant
steps, to share common data, and to discontinue duplicate
processing and calculations), the two systems are simply
interfaced. In fact, many methods for integrating two or
more information systems are really different ways to
build interfaces. You may hear or read the term federated
systems; a federation is simply multiple systems coupled
by interfaces.
Another important objective of an interface is
system decoupling. Two highly coupled system compo-
nents require frequent and rapid communication, thus
creating a dependence and bottleneck in the system. If one
of the components fails, the other cannot function; if one is
modified, the other might also have to be modified.
Appropriately designed interfaces result in the decoupling
of system components. The principal methods of system
decoupling are these:

Slack and flexible resourcesProviding alternative

paths to follow when one component breaks down or

slows down, such as having an interface reroute data

transmissions to public carriers if the company’s

private data communications network becomes busy

BuffersStoring data in a temporary location as a

buffer or waiting line that can be depleted as the data

are handled by the next component, as in collecting

customer orders over the complete day and allowing

an order-filling batch program to allocate scarce

inventory to highest-need jobs

Sharing resourcesCreating shared data stores with

only one program (part of the interface component)

maintaining the data, thus avoiding the need to

synchronize multiple step updating or to operate

with inconsistent multiple copies of data

StandardsEnforcing standards that reduce the need

for two components to communicate, as in adopting

a business policy that requires all interunit transfer of

information about customers to be done using the

company standard customer identification code

Decoupling allows one subsystem to remain relatively

stable while other subsystems change. By clustering

components into subsystems and by applying various

decoupling techniques, the amount of design and mainte-

nance effort can be significantly reduced. Because business

is constantly changing, decoupling can significantly reduce

an organization’s systems maintenance burdens. Decoupling

can also make it easier for an organization to engage in

mergers and acquisitions, or business unit spinoffs. On the

other hand, decoupling often re-creates redundancy, as well

as different cultures and views or understandings and,

hence, can make shared perspectives on organizational

directions more difficult to achieve.

Organizations as Systems

Several useful frameworks exist to conceptualize how

information systems fit into organizational systems. The

framework in Figure 8.5, based on the Leavitt diamond, graph-

ically depicts four fundamental components in an organization

that must work in concert for the whole organization to be ef-

fective: people, information technology, business processes,

and organization structure.Figure 8.5 also suggests that if a

Information

Technology

Business

Processes

People

Organization

Structure

FIGURE 8.5 Fundamental Components of an Organization