device file limitations

[Ernest Small]

Is there a limit to the number of device files a HP-UX 11.11 system can have. If so is there a kernel tune available to up it.

[A. Clay Stephenson]

There is no real limit although there are limits are to the number of addressable devices encoded in the minor device number. For example disk device nodes use 1 byte to represent the controller (bus) instance so that a maximum of 256 SCSI controllers are allowed. Other device drivers have different limits.

[Bharat Katkar]

Hi Small,
Device file is represented with Major and Minor number. Now Majro No. is represents the Class of device so that depends on the class of the device in which it falls.

What remains is your minor no. When you try to list the device file it shows:

brw-r----- 1 bin sys 31 0x040300 Dec 10 16:11 c4t0d3

Here the minor no is 0x040300
What matter is last 4 digits i..e 0300 which represnts the actual device. So the combinations of these 4 digits supported is your max of devices you can have in that particular class.

Hope that helps.
Regards,