C H A P T E R 4 - Peripherals for Sun Ray DTUs

C H A P T E R 4

Peripherals for Sun Ray DTUs

This chapter contains information about selected USB, parallel, and serial devices and printing from Sun Ray DTUs.

Device Nodes and USB Peripherals

Attached Printers

Adapters

There are two kinds of peripherals: serial and parallel. Serial peripherals enable RS-232-style serial connections to the Sun Ray DTU. Parallel peripherals enable printing and come in two types: adapters and direct USB-connected printers.

Third-party adapters are useful for supporting legacy serial and parallel devices.

Sun Ray Server Software recognizes a parallel printer with an adapter as a USB printer.

Device Nodes and USB Peripherals

Sun Ray Server Software creates a device directory called IEEE802.MACID in the /tmp/SUNWut/units directory. This directory contains the MAC address for each DTU on the interconnect. The IEEE802.MACID directory for each DTU contains dev and devices directories. The Sun Ray dev directory contains a representation of the logical topology of the devices connected to the DTU. The Sun Ray devices directory contains a representation of the physical topology of some of the devices connected to the DTU.

Note - Sun Ray Server Software does not create device nodes for every USB device. Some USB device drivers export their device interfaces through other mechanisms than a traditional UNIX device node.

Directories correspond to buses and hubs, and files correspond to ports. Hub directories are named according to the port on the upstream hub into which they are attached.

Device Nodes

In Sun Ray devices, 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. They are named:

 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 is a typical device node path:

[ D ]

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

[ D ]

TABLE 4-1 Definitions of Naming Conventions
Term	Definition
physical topology	The physical topology is hub@port/hub@port and so on. The port refers to the port on the parent hub into which the device or child hub is plugged.
printer name 1, terminal name 1	The printer and terminal name in the Sun Ray `devices` directory is manufacturer, model@port with a colon separating the numerical index when the string just described is not unique in the directory.
printer name 2, terminal name 2	The printer and terminal name in the Sun Ray `dev` directory is the manufacturer and serial number concatenated with an alphabetic index when the serial number is not unique.

This table defines naming conventions.

Device Links

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

manufacturer_name-serial_numberindex

where index is an increasing alphabetical character, starting at a.

If the manufacturer name is not available, the USB vendor and product ID numbers are used for the name of the device link.

Device Node Ownership

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

Hotdesking and Device Node Ownership

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

Changing the active session on a DTU 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 DTU

Logs into a session

Detaches from a session using non-smart card mobility

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 or output to or from any affected device results in an error. Devices currently opened by the superuser remain unaffected by the session change.

Note - When a session is changed, any input or output in progress on a device node opened by a non-root user is cancelled after 15 seconds. If the original session is restored within 15 seconds, the ownership is not relinquished, and input and output continue uninterrupted.

Attached Printers

Sun Ray Server Software supports PostScript printers connected directly to a USB port on the Sun Ray DTU or connected through a USB-to-parallel port adapter. For non-PostScript printer support, refer to Printers Other Than PostScript Printers.

Note - The lp subsystem opens the device node as superuser for each print request, so print jobs are not affected by hotdesking.

Printer Setup

The following generic instructions may vary slightly from one operating system implementation to another but should provide enough information to enable an administrator to set up basic printing services.

To Set Up a Printer

1. Log in as superuser on a Sun Ray DTU.

2. To determine the MAC address of the DTU, press the three audio option keys to the left of the power key in the upper right corner of the keyboard.

The alphanumeric string displayed above the connection icon is the MAC address.

3. To locate the Sun Ray DTU, type:

# cd /tmp/SUNWut/units/*MAC_address

# pwd

 /tmp/SUNWut/units/IEEE802.MACID/

The path to the extended MAC address for your particular Sun Ray DTU is displayed.

4. Locate the port for the printer by typing:

# cd dev/printers

# pwd

/tmp/SUNWut/units/IEEE802.MACID/dev/printers

#ls

printer-node-name

5. In the directory, locate the printer node.

6. Use the Linux administration tools to set up the printer.

Make sure to choose Other so that you can enter the device node from Step 4 above.

7. To verify that the printer has been set up correctly, type:

# lpstat -d printername

Printers Other Than PostScript Printers

Printers that do not use PostScript, such as engineering plotters, are best supported by third-party software. Low-cost inkjet printers require third-party software such as:

Easy Software's ESP PrintPro, available from http://www.easysw.com

Ghostscript, available from http://www.ghostscript.com

Vividata PShop, available from http://www.vividata.com

Check with the vendors for pricing and the precise printer models supported.

Adapters

For a list of verified serial and parallel adapters, see:

http://www.sun.com/io_technologies/sunray/usb/sunray-index.html

libusb

libusb is an Open Source user space USB API that enables applications to access USB devices. It has been implemented for a number of operating environments including Linux, BSD Unix, and Solaris.

The Sun Ray libusb plugin libusbut.so.1 provides Sun Ray-specific support for libusb in Linux environments.

The SUNWlibusbut RPM delivers the Sun Ray libusb plugin libusbut.so.1 in /opt/SUNWut/lib. To build applications, use the usb.h header file from the existing server-side Linux libusb RPM.

The libusbut man page provided with SRSS 3.1 for Linux discusses options available for using the Sun Ray libusb plugin alongside the Linux server-side libusb support.

The Open Source libusb-based applications provided with the standard Linux distributions can be used to drive USB-based devices attached to Sun Ray DTUs. For example, for Sane, see www.sane-proj.org; for Gphoto, see www.gphoto.org.

Note - Sane can be used in Sun Ray implementations if built with threads enabled. Sane binaries with threads enabled are available at the Sun Download Center (SDLC), or they can be built from source.