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. > > That helps immensely, thank you > > I would presume that to learn more about this > subject I would have to delve into kernel > construction. I should count my blessings > that it was made this easy. > > Walt
There are no such files, the information is in MAKEDEV, which is a script, so look into it ! Each device has a major and a minor number (just do an ls -l in /dev, these numbers are after the user & group names). The only thing MAKEDEV knows is that lp3 is major 6, minor 3; the rest is on the parport driver, who registers itself as handler of major 6 devices. When a process opens lp3, the kernel sends the request to the driver who handles the #6 devices, and passes the minor number to it as an argument. Thus the parport driver will know that he was requested to open the fourth parallel port. HTH Lehel
