The Pilot operating system is designed for the personal computing environment. It provides a basic set of services within which higher-level programs can more easily serve the user and/or communicate with other programs on other machines. Pilot omits certain functions sometimes associated with “complete” operating systems, such as character-string naming or user-command interpretation; higher-level software provides such facilities as needed. On the other hand, Pilot provides a higher level of service than that normally associated with the “kernel” or “nucleus” of an operating system. Pilot is closely coupled to the Mesa programming language and runs on a rather powerful personal computer, which would have been thought sufficient to support a substantial timesharing system of a few years ago. The primary user interface is a high resolution bit-map display, with a keyboard and a pointing device. Secondary storage generally takes the form of a sizable local disk. A local packet network provides a high bandwidth connection to other personal computers, and to server systems offering such remote services as printing and shared file storage.