Method and apparatus for providing multiple sessions on a single user operating system

A set of operating system extensions that allow a single user operating system to support multiple users is disclosed. The extensions operate by creating multiple sets of operating system environments by copying a number of operating system variables that define the current operating system state. In a two user embodiment, a local personal computer console state is created for the user at the personal computer console and a remote console system state is created for a user at a remote console coupled to the personal computer system. A special virtual device driver then hooks into the operating system such that the special virtual device driver will be called before any thread switch. The special virtual device driver will load the proper operating system environment variables for the application that will be executed next. The operating system extensions also handle all input and output requests in a special manner. When the operating system extensions are initialized, a set of drivers is loaded for each user. The operating system extensions then hook all input and output operating system calls such that all the operating system extensions direct all input and output requests from applications run by a user at the personal computer console are directed toward the normal set of personal computer device drivers but all input and output requests from applications run by another user at another console are directed toward a set of device drivers for that user's console.