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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?).

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