Abstract: Improved techniques for controlling buses of a computer system are disclosed such that peripheral devices (and/or their associated buses) can be connected or disconnected to the computer system while the computer system is active. The peripheral devices are connected to the computer system by being inserted into a slot or other receptacle of the computer system. The peripheral devices are disconnected from the computer system by being removed from a slot or other receptacle of the computer system. The slots or receptacles typically includes connectors designed to receive peripheral devices, such as PC CARD slots, expansion bays, and the like. Given that the peripheral devices can be inserted or removed while the computer system is active is active, the computer system according to the invention permits “hot-plugging” of peripheral devices. The invention is particularly well suited for controlling PCI buses for peripheral devices connecting to a computer system by way of peripheral ports.