Creating device nodes

6.18 LPAR mode z/VM guest KVM guest

User space programs access DASDs by device nodes. Your distribution might create the device nodes for you, but you can also create your own device nodes.

About this task

If no device nodes are created for you, you must create them yourself, for example, with the mknod command. See the mknod man page for further details.

Tip: Use the device names to construct your nodes.

Example

The following nodes use the form /dev/<device_name> for the device nodes. The assignment of minor numbers is according to the following table:

Table 1. Mapping of DASD names to minor numbers
This table has two header rows. The first two entries in the top row describe device names and minor numbers, respectively, and span two columns each. The columns in the second row always describe the first and last name or minor number of a range. The fifth and last column has a single header and specifies the total number of devices in the specified range. There are 5 data rows, 4 of which describe device ranges. The final data row has a single cell with the total device count.
Name for device as a whole		Minor number for device as a whole		Number of devices
From	To	From	To	Number of devices
dasda	dasdz	0	100	26
dasdaa	dasdzz	104	2804	676
dasdaaa	dasdzzz	2808	73108	17,576
dasdaaaa	dasdnwtl	73112	1048572	243,866
Total number of devices:				262,144

 # mknod -m 660 /dev/dasda  b 94 0
 # mknod -m 660 /dev/dasda1 b 94 1
 # mknod -m 660 /dev/dasda2 b 94 2
 # mknod -m 660 /dev/dasda3 b 94 3
 # mknod -m 660 /dev/dasdb  b 94 4
 # mknod -m 660 /dev/dasdb1 b 94 5
 ...