PC-Hypertext: Attributes 3. - PC-Hypertext can be configured to contain calls to DOS programs external to the authored application. When a system user activates a "program call", the PC-Hypertext program stores the information necessary to describe the current user location in the authored application, and then temporarily exits from memory. The system memory is then allocated in support of the external (called) program. When user interaction with the external program is terminated, PC-Hypertext is automatically reloaded to the system and the user is returned to the last active display prior to the implementation of the external program call. PC-Hypertext: Attributes 1.