HP StorageWorks DAT Tape Drives User Guide - USB (April 2005)

Troubleshooting42
3. If the problem persists, check the environmental conditions against the specified limits (refer to
www.hp.com
). Perhaps move the drive to a more suitable site.
 Has a new operating system been installed in the host computer? Has new backup software
been installed?
The problem could lie with the host or the software. Consult the computer’s operating manuals,
the software manual, or seek help from a service engineer.
Verifying USB installation for optimum performance
To confirm that an HP StorageWorks USB DAT drive is installed correctly:
• Check that a USB 2.0 port is being used
• Ensure that the tape drive is the only device on a USB hub
• Ensure that the hp_usbstor driver is being used
Check for USB 2.0 port (Windows)
It is important to ensure that you connect your drive to a USB 2.0 port. The drive will work on a USB
1.1 port but performance will be severely degraded.
To check the port on a Windows system:
1. Go to Device Manager and select Devices by connection from the View menu.
2. Expand Universal Serial Bus controllers and locate the tape drive.
3. If a USB driver is listed as Enhanced, the port is USB 2.0. See Figure 20 on page 43.
Ensure that the tape drive is the only device on a USB hub (Windows)
On some computers multiple physical USB 2.0 ports will be connected to the same master port,
known as a “root hub”. Connecting multiple devices to one root hub may degrade tape drive
performance degradation.
USB Mass Storage devices like HP DAT tape drives have the lowest priority of all device types on the
USB bus, so devices such as webcams should never be connected to the same root hub.
To check the devices connected to a root hub:
1. Go to Device Manager and select Devices by connection from the View menu.
2. Expand Universal Serial Bus controllers and locate the tape drive.
3. Trace the tree of devices back to the USB Root Hub and check that the only device connected is
the tape drive via the HP USB Mass Storage Device. See Figure 20 on page 43 for an example
showing a single tape device connected to a dedicated USB 2.0 root hub.
Ensure that the hp_usbstor driver is being used (Windows)
The HP StorageWorks USB DAT drive will work with the Microsoft usbstor driver, however, HP
strongly recommends that you use the hp_usbstor driver for improved performance.
To check the driver being used:
1. Go to Device Manager and select Devices by connection from the View menu.