System for enabling access to device driver residing in resource memory corresponding to coupled resource by allowing memory mapping to device driver to be executed

摘要

Device drivers for removable system resources are configured dynamically in a computer system having a processor, a system memory and an interface for receiving removable system resources (generally denoted feature cards). A feature card has a card memory area which stores a device driver for controlling the feature card. The feature card device driver is separated into two parts: 1) a full device driver portion, and 2) a stub device driver portion. The full device driver provides all of the device driver functionality necessary to control each and every function of the feature card. The device driver stub is a small compact portion of processing logic for linking the full device driver with operating system software located in the computer system. A fixed amount of system memory RAM is set aside at bootstrap initialization to contain the device driver stubs. Device driver stubs corresponding to removed cards remain resident in system memory until a device driver stub cannot be loaded because the system memory set aside for device driver stubs has been filled. At that time, enough of the system memory set aside for device driver stubs is reclaimed to permit the desired device driver stub to be loaded. Therefore, by allocating enough space in computer system memory to contain every device driver stub required by the system at a given time, and by reclaiming system memory occupied by removed card device driver stubs as the system memory is needed, one can avoid having to periodically reset the system by performing a bootstrap initialization procedure.