The Subject and Object of Compatibility Rules

As you can see in this example, compatibility rules consist of:

• Subject. The product that requires or excludes another product. In the examples, the computer is the subject.

• Type of Rule. The type is either requires or excludes.

• Object. The product that is required or excluded. In the examples, the monitor is the object.

Requires rules apply in only one direction. If the subject requires the object, the object does not necessarily require the subject. For example, the Turbo computer requires a Standard monitor. However, the Standard monitor does not necessarily require the Turbo computer; it can also be used with other computers.

Excludes rules apply in both directions. If the subject excludes the object, the object necessarily excludes the subject. For example, the Turbo computer does not work with the Flat-screen monitor, and that necessarily means that the Flat-screen monitor does not work with the Turbo computer.