USB 2.0 DAT-Drive - no USB 2.0 speed under FreeBSD?

Ewald Jenisch a at
Tue Nov 15 14:47:57 GMT 2005


I've got a DAT72 (DDS-5) external tape drive (HP C7438A) that connects
via USB (!). However I can't get it to work as USB2.0 drive under
FreeBSD (5.4) :-(

When starting the drive here's what I get in /var/log/messages:

Nov 13 20:06:10 tasty kernel: umass0: Hewlett Packard DAT72 USB Tape,
rev 2.00/30.30, addr 2
Nov 13 20:06:10 tasty kernel: sa0 at umass-sim0 bus 0 target 0 lun 0
Nov 13 20:06:10 tasty kernel: sa0: <HP C7438A ZU55> Removable
Sequential Access SCSI-3 device
Nov 13 20:06:10 tasty kernel: sa0: 1.000MB/s transfers

Sure enough I've got my kernel compiled with "device ehci" as per the
following excerpt from my kernel config file:

# USB support
device          uhci            # UHCI PCI->USB interface
device          ohci            # OHCI PCI->USB interface
device          ehci            # EHCI PCI->USB interface (USB 2.0)
device          usb             # USB Bus (required)
#device         udbp            # USB Double Bulk Pipe devices
device          ugen            # Generic
device          uhid            # "Human Interface Devices"
device          ukbd            # Keyboard
device          ulpt            # Printer
device          umass           # Disks/Mass storage - Requires scbus 
device          ums             # Mouse
device          urio            # Diamond Rio 500 MP3 player
device          uscanner        # Scanners

When I try to write to the drive either via dump ("dump 0a -f /dev/sa0
<filesys>") or plain "dd" the drive runs in start/stop-mode,
i.e. starting and stopping tape movement every few
seconds. Performance is sluggish to say the least (about 1MB/sec)
besides the fact that frequent start/stop is not the best for both
drive and tape.

Please note that this drive works without problems, esp. with full
performance (i.e. USB2.0) under Windows though (same machine), so I
don't assume it has something to do with the drive per se.

So here are my questions:

o) Has anybody out there got the external USB DAT72-Drive vom HP got
working under FreeBSD (5.x) with full USB2.0 performance?  (here's a
link to the specs etc.

o) How can I find out whether my drive is actually working as USB1.x
or USB2.0-device (apart from concluding that start/stop-mode must be
because it's working as USB1.x-device).

Thankx much in advance for your help,

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