Everything under linux is accessed as if it was a file.
There is no gegistry, like in windows, to keep track of things.
For example, the first master hard disk under linux is accessed by accessing the file /dev/hda. the first partition under this drive is accessed by accessing /dev/hda1.
My scanner can be accesed under /proc/bus/usb/002/002.
The information of my cpu can be accessed by accesing /proc/cpuinfo.
Application settings are kept in files (no registry.)
And so on.