From the enterprise perspective, computer systems are the components that make up the overall architecture of a company's systems. Ideally, the computer systems will merge into the background and the business use of these tools of automation will come to the fore. This shift in focus requires that the computer systems act as components in a larger operation where the differences between the components have been resolved.
For instance, the application used by a company's sales force to track customer leads, contacts, and sales might be one component. That one component can have several different versions in a large company, when different sales offices have implemented the same system differently, or have even installed different software. It's not uncommon for sales offices in separate geographical locations to operate independently from each other, installing and maintaining their own computer systems separately. When such is the case, those systems will probably not be able to inter-operate and share data because their definitions for that data, and for the operations applied against it, won't match. So a company's sales systems in Omaha won't be compatible with the same company's sales systems in Akron.
Another component might be the software used by the marketing department to forecast customer demand for services or products and to track promotions, market trends, and customer behaviors. This type of software often uses an entirely different scheme to represent customer information, with definitions that are meaningful to marketing but not necessarily meaningful to sales. Marketing tends to look at trends among demographically defined groups of customers, for example, whereas the sales department is more likely to track information on contacts with a specific customer.
Both the sales and marketing software components store information about customers, but from two or more different perspectives, often with different definitions of what information is needed about customers. To say that the interfaces between these components are seamless means that in spite of their different relationships to the customer, the computer systems have been configured to use compatible definitions of important pieces of customer information. The operations or business rules applied against that data (such as calculations, transformations, and categorization) are also compatible. In other words, they have seamless interfaces that basically become irrelevant to the business owner's ability to use them to conduct business.