Device and Drivers
When the kernel is booted or is loaded into memory it detects the hardware attached to the system
via "devfs", also devfs is continuously probing for new hardware if it is attached to the system and if
drivers are there then the device is ready to use.
Kernel comes to knows via "devfs" whether hardware has changed or not i.e
for example "hot swapping of hard drives", "hot swapping of PCI devices"
Now, Hardware are referenced by three ways
Devices which are physically connected to the system are referenced in the /devices directory
"devfs" is responsible for mounting the /devices and it is in memory.
devfs solely manages the /devices directory, however administrator could use devfsadm to manage
however that is normally not required.
Even though the devices are physically referenced in the /devices directory, we use the devices via
their logical representation which are stored in the /dev directory.
i.e /dev holds the logical representation of the physical device. If you go the /dev directory you will find
symbolic links to physical representation i.e to /devices directory.
Also utilities such as format, prtconf, sysdef etc use the logical representation i.e /dev to interact with the
devices attached to the system
Contains current hardware instances, entries in this file represent the hardware connected to the system.
Names listed here are used by the kernel to interact with the hardware device.