From IBM XT/PC handbook, you find the port addresses for all the components originally designed in the computer, and your bios takes care of elementary data i/o operations.

Then we decided in 1993 to have hot plug capability in ISA and PCI card slots. Plug and play operating system was born, very same idea as the hot plugged USB devices of today. It just means the circuits have to add buffers for i/o connections to sustain zaps from sudden voltage inputs and outputs. The connectors can take a 35 volt spike without circuit failures(a reversed diode to block high voltage).

Bios already had 2 code beep error signal. And 3 code process codes. So, a four digit code is used for component recognition. For instance, sound chipset cmi8738 would be recognized as 8738 and the Pnp Os will install the cmi sound drivers from the operating system. But cmi also had 8737 chipset, so bios with early PnP Os will have fuzzy logic to install any drivers close to 8738. Those PNP Os became known as Plug and pray you are right operating system. Today, we have more exact 4 digit codes for chipsets, and drivers can be more specific.

Then, ambiguous device components ware the rage, by using DSP to simulate any device and operate with firmware. The 4 digit codes had to be in the firmware. the earlier ones had nothing in the firmware, and drivers had to have firmware first before drivers can be installed.

With windows Vista, componentized drivers now have firmware, and drivers of selected componentized instructions, and you can use all the functions of the best drivers or only a few elementary instructions. This works well with microkernels of single instruction.

Linux on the other hand usually start with common denominated instructions of a very few functions, then add on more functions as the computers gets more modern. Linux drivers can be easily componentized in groups of more and more sophistication.