今天在终端(非图形界面)挂载U盘，遇到一系列问题：
flc@ubuntu:~$ sudo mount -t vfat -o iocharset=utf8 /dev/sdb1 /media/udisk
mount: special device /dev/sdb1 does not exist
flc@ubuntu:/$ sudo fdisk -l
Disk /dev/sda: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders, total 62914560 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00082ba2
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 61868031 30932992 83 Linux
/dev/sda2 61870078 62912511 521217 5 Extended
/dev/sda5 61870080 62912511 521216 82 Linux swap / Solaris
Disk /dev/sdb: 8011 MB, 8011120640 bytes
247 heads, 62 sectors/track, 1021 cylinders, total 15646720 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x6f20736b
This doesn't look like a partition table
Probably you selected the wrong device.
Device Boot Start End Blocks Id System
/dev/sdb1 778135908 1919645538 570754815+ 72 Unknown
/dev/sdb2 ? 168689522 2104717761 968014120 65 Novell Netware 386
/dev/sdb3 ? 1869881465 3805909656 968014096 79 Unknown
/dev/sdb4 ? 2885681152 2885736650 27749+ d Unknown
Partition table entries are not in disk order
老是说special device /dev/sdb1 does not exist，无比郁闷
我以为是前几天量产优盘，优盘的分区表搞出问题了。
又发现：
#fdisk /dev/sda
然后输入a，确定，再输入w，确定。
接着就可以mount了。
估计
Device Boot Start End Blocks Id System
/dev/sdb1 778135908 1919645538 570754815+ 72 Unknown
/dev/sdb2 ? 168689522 2104717761 968014120 65 Novell Netware 386
/dev/sdb3 ? 1869881465 3805909656 968014096 79 Unknown
/dev/sdb4 ? 2885681152 2885736650 27749+ d Unknown
是有个?这个咚咚。。。。
量产优盘，优盘分区表问题大大的有了。我当时没备份分区表，把它量产成活动的，用来做启动盘，在windows下也没什么问题，就没想到它在linux很难识别该U盘。
如果大家想量产的话，建议先纪录量产前的u盘的信息，推荐用chip genius（查看vid、vid\\序列号之类）还有PowerQuest Partition Table Editor（查看修改分区表）还有Eisoo DiskGenius(磁盘管理修复) ，备份分区表和详细信息，否则想恢复的时候可能就很麻烦。
我装了autofs服务：
flc@ubuntu:~$ sudo apt-get install autofs
flc@ubuntu:~$ sudo fdisk /dev/sdb
Command (m for help): a
Partition number (1-4): 1
Command (m for help): m
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition's system id
u change display/entry units
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
最后：
flc@ubuntu:~$ sudo mount -t vfat -o iocharset=utf8 /dev/sdb /media/udisk
分区不要1 ？，挂载成功！