Messages are not the same as status codes (see Status Codes). Messages are returned to end users by utilities or specific components and generally begin with a prefix and a number. For example: MKDE-16: There is insufficient memory to load the MicroKernel Engine.

The status code is tied to a particular component, and it varies depending on the nature and source of the error. The value for nn or xx refers to a software-supplied number (for example, a status code, operation code, or number of records) and xxxx refers to a software-supplied name (for example, a filename, a data type or key type, or a command).