Device links are created under the dev directory. A link to each serial node is created in dev/term, and a link to each locally attached printer is created in dev/printers.

Typical device links are:

/tmp/SUNWut/units/IEEE802.080020cf428a/dev/term/manufacturer_name-67a
/tmp/SUNWut/units/IEEE802.080020cf428a/dev/printers/1608b-64

The device link for the first example is manufacturer_name-serial_numberindex, where index is an increasing alphabetical character, starting at a. If the manufacturer name is not available, the vendor and product ID numbers are used for the name of the device link.

Here is an example of the dev directory from a Sun Ray 3 Client, which has an onboard serial port.

# cd $UTDEVROOT/dev
# pwd
/tmp/SUNWut/units/IEEE802.002128587259/dev
# ls     
term 
# cd $UTDEVROOT/dev/term
# pwd
/tmp/SUNWut/units/IEEE802.002128587259/dev/term
# ls -l
lrwxrwxrwx   1 root     root          22 Jul 28 17:23 a -> ../../devices/serial:a       

In the devices directory, device nodes are created for each serial or printer port on an attached USB device. The device nodes are created in the hub directory corresponding to the hub to which they are attached. The nodes are named as follows:

manufacturer_name,model_name@upstream_hub_port

If the USB device has multiple identical ports (for example, two serial ports), the name is followed by :n where n is a numerical index, starting at 1.

The following example is a typical device node:

/tmp/SUNWut/units/IEEE802.MACID/devices/usb@1/hub@1/manufacturer_name,model_name@3:1

Here are the definitions of the naming conventions.

Some device nodes are owned by the user whose session is active on the client, while others might be owned by root or by other users that had previously active sessions on the client. Device permissions, access controls and ownership rules are determined by the class of device. For serial devices, only the user whose session is active on the client or the superuser have permission to use the attached device. If no user has an active session, superuser owns the serial device nodes. This rule might not be applicable for other classes of USB devices connected to the client.

The following description of the behavior of USB devices when sessions are connected and disconnected from a client applies only to serial devices. Other device classes may have different semantics regarding ownership and device lease times.

Changing the active session on a client changes the ownership of the device nodes to the user associated with the new session. A session change occurs whenever a user inserts or removes a smart card from a client or logs into a session.

In a failover environment, you can use the utselect or utswitch command to change a session. A session change causes all devices currently open by a non-root user to be closed after 15 seconds. Any input to or output from any affected device results in an error. For a serial device node, if the original session is restored within 15 seconds, the ownership is not relinquished, and input and output continue uninterrupted.

Devices currently opened by the superuser, including normal printing, remain unaffected by a session change.

To use serial attached devices with a client, you must attach them to the internal serial ports or through a USB-to-serial adaptor. You must use USB redirection in a Windows session to access a serial device connected through a USB-to-serial adapter.

Symbolic links to the serial port device nodes are located under $UTDEVROOT/dev/term. Built-in ports are named "a" or "b".

Serial ports become unowned during hotdesking, so you should make sure any serial port activity is stopped before removing your smart card or resetting the client.

This section provides instructions on how to setup PostScript and non-attached PostScript printers that are attached to the Sun Ray Client. For details on how to print from Windows while using the Windows connector, see Chapter 17, Windows Connector.