Virtual device descriptions

This topic provides information about configuring and naming virtual device descriptions.

Telnet uses virtual device descriptions to maintain client workstation information for open Telnet sessions. A virtual device is a device description that is used to form a connection between a user and a physical workstation attached to a remote system. Virtual devices provide information about your physical device (display or printer) to the programs on the server. The server looks for the attaching client/server protocol to specify a virtual device. If the server cannot find a specified virtual device, it then looks for a designated virtual device in a registered exit program. If the server cannot find a virtual device, it then attempts to match a virtual device description with a device type and model similar to the device on your local system.

Telnet naming conventions for virtual controllers and devices

The Telnet server uses the following conventions for naming automatically created virtual controllers and devices, according to the i5/OS^® standards:

For virtual controller, the server uses the name QPACTL nn where nn is a decimal number of 01 or greater.
For virtual devices, the server uses the name QPADEV xxxx where xxxx is an alphanumeric character from 0001 to zzzzz, excluding vowels.
For named virtual devices, the server gives the virtual controllers the name of QVIRCD nnnn

Notes:

Under the i5/OS naming convention, the virtual controller must have a name of QPACTL nn.
The virtual device has a name of QPADEV xxxx.
You must grant the QTCP user profile authority to the user-created virtual devices.
You can change the naming conventions for automatically created virtual devices by using the *REGFAC option of QAUTOVRT. Refer to QAUTOVRT in the System Values topic for more information.

The number of sign-on attempts allowed increases with automatically configured virtual devices. The total amount of sign-on attempts is equal to the number of system sign-on attempts that are allowed, multiplied by the number of virtual devices that can be created. The Sign-on System Values define the number of sign-on attempts allowed.

The Telnet server reuses available existing virtual devices that were automatically created by selecting virtual devices of the same device type and model. When no more device types and models match but virtual devices are still available, then the device type and model are changed to match the client device and model negotiated. This is true for both automatically created (QPADEV xxxx ) virtual devices, and named virtual devices.

If you choose to manually create your own devices, you should establish naming conventions that allow you to easily manage your configuration. You can select whatever device names and controller names that you want, provided that the names conform to the i5/OS object naming rules.

For procedures for creating virtual devices, see Set the number of virtual devices.