RE: Making new "/dev" entries
On 07-Jul-2000 Walter Williams wrote:
> So it sounds like there are files containing
> pre-defined information for making /dev entries.
> I would therefore conclude that it knows that
> "lp3" would be a printer port and configures
> it accordingly.
files in /dev are special files. if you ls -l one:
crw-rw---- 1 root audio 14, 4 Jun 23 1999 /dev/audio
you see the normal permission info, who owns it, date touched, etc.
But note the extra data '14, 4'. These are major and minor numbers. These
numbers map into a table in the kernel. So 14,4 -> sound module.
brw-rw---- 1 root disk 8, 16 Mar 3 1999 sdb
8,16 second scsi disk and so on.
This file existing only means that you can try to access the device. The
kernel must be configured to support a device (having the sound module) and the
actual device support must be configured (what sound module? what irq?).