According to the patent, a user account created at a multi-user computer can be stored to an external, portable data store, thereby rendering the user account portable. The multi-user computer system, e.g., through its operating system, locates user accounts on not only in local storage of the multi-user computer system, but also in any removable data storage attached to the multi-user computer system.

So, by coupling the external, portable data store to another multi-user computer, a user is able to login to any supporting multi-user computer and be presented with their user configuration and user directory. Since the data store that stores the user account is not only external but also portable, a user can simply tote the data store to the location of different multi-user computers. In one embodiment, the external, portable data store can not only store the user account but can also provide general data storage. In another embodiment, the external, portable data store can be a portion of a portable computing device (e.g., media player) that provides other functionality besides data storage.

Here's Apple's summary of the invention: "The invention relates to improved approaches for enabling user accounts to be portable across different multi-user computer systems. A user account can be stored to an external, portable data store, and thus the user account becomes portable. Hence, by coupling the external, portable data store to another multi-user computer system, a user is able to login to any supporting multi-user computer system and be presented with their user configuration and user directory. Since the data store that stores the user account is not only external but also portable, a user can simply tote the data store to the location of the multi-user computer system. In one embodiment, the external, portable data store is able to be coupled to the multi-user computer system for data transfer there between.

"The external, portable data store can merely provide data storage or can be a portion of a portable computing device that provides other functionality besides data storage. One example of a portable computing device is a media player.

"The invention can be implemented in numerous ways, including as a method, system, device, apparatus, or computer readable medium. Several embodiments of the invention are discussed below.

"As a method for configuring a multi-user computer system for use by a registered user, the multi-user computer system including at least a processor, an operating system, a display device and a local data store, one embodiment of the invention includes at least the acts of: retrieving available user accounts pertaining to registered users, at least one of the available user accounts being from the local data store that is within the multi-user computer system and at least another of the available user accounts being from an external data store that is external to the multi-user computer system; presenting a representation of the retrieved available user accounts on the display device of the multi-user computer system; receiving a selection of one of the retrieved available user accounts by the registered user; authenticating the registered user as authorized for use of the selected one of the retrieved available user accounts; and configuring the multi-user computer system in accordance with the selected one of the retrieved available user accounts for use by the registered user.

"As a method for establishing a portable user account for a user on a multi-user computer system, one embodiment of the invention includes at least: receiving account information for the user; producing an account record based on at least the account information; storing the account record to a portable data store, the portable data store being separate and apart from the multi-user computer system yet operatively connectable with the multi-user computer system; and creating a default folder for the user on the external data store.

"As a method for establishing a user account for a user on a multi-user computer system, one embodiment includes at least the acts of: receiving account information for the user; displaying a list of available data stores on which the user account can be created, the list of available data stores including at least one internal data store and at least one external data store; receiving a selection of one of the available data stores; producing an account record based on at least the account information; and storing the account record to the selected one of the available data stores.

"As a computer readable medium including at least computer program code for configuring a multi-user computer system for use by a registered user, the multi-user computer system including at least a processor, an operating system, a display device and a local data store, one embodiment of the invention includes at least: computer program code for retrieving available user accounts pertaining to registered users, at least one of the available user accounts being from the local data store that is within the multi-user computer system and at least another of the available user accounts being from a portable data store that is connectable to the multi-user computer system; computer program code for presenting a representation of the retrieved available user accounts on the display device of the multi-user computer system; computer program code for receiving a selection of one of the retrieved available user accounts by the registered user; computer program code for authenticating the registered user as authorized for use of the selected one of the retrieved available user accounts; and computer program code for configuring the multi-user computer system in accordance with the selected one of the retrieved available user accounts for use by the registered user.

"As a computer readable medium including at least computer program code for establishing a portable user account for a user on a multi-user computer system, one embodiment of the invention includes at least: computer program code for receiving account information for the user; computer program code for producing an account record based on at least the account information; computer program code for storing the account record to a portable data store, the portable data store being separate and apart from the multi-user computer system yet operatively connectable with the multi-user computer system; and computer program code for creating a default folder for the user on the external data store.

"As a computer readable medium including at least computer program code for establishing a user account for a user on a multi-user computer system, one embodiment of the invention includes at least: computer program code for receiving account information for the user; computer program code for displaying a list of available data stores on which the user account can be created, the list of available data stores including at least one local data store and at least one portable data store; computer program code for receiving a selection of one of the available data stores; computer program code for producing an account record based on at least the account information; and computer program code for storing the account record to the selected one of the available data stores.

"As a multi-user computer system, one embodiment of the invention includes at least an external data storage device and a multi-user computer. The external data storage device is removable from the multi-user computer and portable. The multi-user computer has an operating system that includes at least an account creation module and a login module. The account creation module permits new user accounts to be created and stored to the external storage device. The login module permits login with respect to users having their user accounts stored to the external data storage device."

The inventors are Steve Ko and Robert T. Bowers. The graphic below is a simplified block diagram of a multi-user computer system according to one embodiment of the invention.