Terminal device nodes
Applications, for example, login programs, access terminal devices by device nodes.
Table 1 lists the standard device nodes the terminal devices. Which terminal devices are present on your system depends on your system environment, LPAR or z/VM®, on your kernel parameters, and on the presence of online 3270 devices.
| Device driver | On LPAR | On z/VM | On KVM | Major | Minor |
|---|---|---|---|---|---|
| SCLP line-mode terminal device driver | /dev/sclp_line0 | /dev/sclp_line0 | /dev/sclp_line0 | 4 | 64 |
| SCLP VT220 terminal device driver | /dev/ttysclp0 | /dev/ttysclp0 | /dev/ttysclp0 | 4 | 65 |
| 3215 line-mode terminal device driver | n/a | /dev/ttyS0 | n/a | 4 | 64 |
| 3270 terminal device driver | /dev/3270/tty1 to /dev/3270/tty<N> | /dev/3270/tty1 to /dev/3270/tty<N> | /dev/3270/tty1 to /dev/3270/tty<N> | 227 | 1 - <N> |
| z/VM IUCV HVC device driver | n/a | /dev/hvc0 to /dev/hvc7 | n/a | 229 | 0 - 7 |
| virtio-console device driver | n/a | n/a | /dev/hvc0 to /dev/hvc<n> | 229 | 0 - <n> |
Apart from the standard device nodes, there is also a generic device node, /dev/console, that maps to the current console. The console device driver itself presents /dev/console as a pure input device to the user space. However, through its association with the terminal device driver, it becomes bidirectional.
Your distribution must create these device nodes early in the boot process, for example, with udev. Otherwise, Linux® might not boot and leave you without a command prompt for creating the nodes yourself. In this case, you can create the nodes from a support system that has access to the root file system of the failed Linux instance.