Hot removable and insertion of attachments on fully initialized computer

Abstract

A computer having slots for attachment of expansion adapters contains means enabling the system formed by the computer and attached adapters to reconfigure automatically, when an adapter is either inserted into an empty slot or removed from an occupied slot, while the system is fully powered and in an application running state. Insertion of an adapter into an empty slot is detected by an adapter detection mechanism. The mechanism signals a programmed resource manager element in the computer, via an interrupt or the like, and the resource manager then sequences the computer and inserted adapter through a series of mechanical and electrical reconfiguring operations. In these operations, the adapter is physically locked into place relative to the slot, supplied with power from a source in the computer, and signal conduction paths through the slot are activated. Thereafter, attribute information stored by the adapter is read out to the computer and the computer conducts a setup process to modify its configuration information to establish proper communication levels and addresses for the adapter commensurate with then active resources of the system. To remove an installed adapter, a user issues an adapter removal request to the resource manager, via an adapter removal button. In response to such request, the resource manager checks the running state of the adapter. If a data transfer is being conducted relative to the adapter, further operation in response to the request is delayed until the transfer is completed. When the request can be handled, the resource manager electrically isolates and mechanically releases the adapter, allowing the user to remove it.