How to visit U disk?

Michaël Grünewald michael.grunewald at
Wed Aug 13 17:08:13 UTC 2008

EdwardKing wrote:
> Thanks your answer!
> I use dmesg | tail
> #dmesg | tail
> sc0: VGA <16 virtual consoles, flags=0x300>
> vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
> Timecounter "TSC" frequency 2194304266 Hz quality 800
> Timecounters tick every 1.000 msec
> hptrr: no controller detected.
> ad0: 5120MB <VMware Virtual IDE Hard Drive 00000001> at ata0-master UDMA33
> acd0: CDROM <VMware Virtual IDE CDROM Drive/00000001> at ata1-master UDMA33
> Waiting 5 seconds for SCSI devices to settle
> GEOM_LABEL: Label for provider acd0 is iso9660/FreeBSD_Install.
> Trying to mount root from ufs:/dev/ad0s1a

If you issued the command right after you plugged the USB stick in your 
system, it has not been detected. The last line

> #mount_msdosfs ufs:/dev/ad0s1a  /mnt
> mount_msdosfs ufs:/dev/ad0s1a: : Operation not permitted

Because there is no file ufs:/dev/ad0s1a, note that ufs: is not part of 
the path of the device in the file system.

> #mount_msdosfs /dev/ad0s1a  /mnt
> mount_msdosfs /dev/ad0s1a: : Operation not permitted

Because the /dev/ad0s1a device is already mounted as the root file system.

> #device umass
> device: not found

The shell says there is no command `device'.

It seems you would take advantage from reading section «18. Storage» in 
the Handbook, especially section 18.2 that explains thow to recognize 
devices after their names, and section 18.5 that is devoted to USB 
devices. Again, the URL for section 18 is:

(Note that top-posting obfuscates the dialog history, so it is best to 
avoid top-posting.)

> ----- Original Message ----- 
> From: "Michaël Grünewald" <michael.grunewald at>
> To: "EdwardKing" <zhangsc at>
> Sent: Wednesday, August 13, 2008 1:46 PM
> Subject: Re: How to visit U disk?
>> EdwardKing wrote:
>>> I want to use U disk which format is FAT32,I don't know how to visit
>>> U disk,my dev directory is follows: #cd /dev #ls ... usb usb0 usb1 
>>> ...
>>> How to do it? Thanks in advance
>> After you plug the stick in the system, it is attached by the kernel
>> which issues some information. This information is visible in the
>> console, you can also access it with the dmesg utility:
>>   $ dmesg | tail
>>   umass0: <Sony Storage Media, class 0/0, rev 2.00/1.00, addr 2> on 
>> uhub4
>>   da0 at umass-sim0 bus 0 target 0 lun 0
>>   da0: <Sony Storage Media 0100> Removable Direct Access SCSI-0 device
>>   da0: 40.000MB/s transfers
>>   da0: 247MB (506880 512 byte sectors: 64H 32S/T 247C)
>>   GEOM_LABEL: Label for provider da0s1 is msdosfs/USBSTICK.
>> You can see above example output from my system.
>> The stick is available here through `/dev/da0s1' or through
>> `/dev/msdosfs/USBSTICK'.
>> Not that some environements will automagically mount the stick for you,
>> usually at some directory under /var/media.
>> You may also want to read parts of the `Storage section' in the Handbook:

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