转贴 解决sd卡的读写问题

最近sd卡读写出了问题，参考一篇网志解决。
http://sns.linuxpk.com/space-1717-do-blog-id-15748.html
在
embedded linux

下插上一个
U

盘，在
/dev/scsi/

目录下，出现了
4

个
part

。把该
U

盘插在
pc

机，在
windows

下正常。在
Redhat linux

系统下
mount

的时候出现错误。在使用
fdisk –l

命令。显示问题如下。

Disk /dev/sdb: 1023 MB, 1023409152 bytes

32 heads, 61 sectors/track, 1023 cylinders

Units = cylinders of 1952 * 512 = 999424 bytes

This doesn't look like a partition table

Probably you selected the wrong device.

Device Boot Start End Blocks Id System

/dev/sdb1 ? 398636 983425 570754815+ 72 Unknown

Partition 1 has different physical/logical beginnings (non-Linux?):

phys=(357, 116, 40) logical=(398635, 6, 23)

Partition 1 has different physical/logical endings:

phys=(357, 32, 45) logical=(983424, 30, 61)

Partition 1 does not end on cylinder boundary.

/dev/sdb2 ? 86419 1078237 968014120 65 Novell Netware 386

Partition 2 has different physical/logical beginnings (non-Linux?):

phys=(288, 115, 43) logical=(86418, 26, 1)

Partition 2 has different physical/logical endings:

phys=(367, 114, 50) logical=(1078236, 17, 53)

Partition 2 does not end on cylinder boundary.

/dev/sdb3 ? 957932 1949749 968014096 79 Unknown

Partition 3 has different physical/logical beginnings (non-Linux?):

phys=(366, 32, 33) logical=(957931, 2, 32)

Partition 3 has different physical/logical endings:

phys=(357, 32, 43) logical=(1949748, 25, 36)

Partition 3 does not end on cylinder boundary.

/dev/sdb4 ? 1478321 1478349 27749+ d Unknown

Partition 4 has different physical/logical beginnings (non-Linux?):

phys=(372, 97, 50) logical=(1478320, 8, 25)

Partition 4 has different physical/logical endings:

phys=(0, 10, 0) logical=(1478348, 22, 13)

Partition 4 does not end on cylinder boundary.

Partition table entries are not in disk order

经过网上查找和自己动手，找到解决方法。

fdisk
/dev/sdb1 (

此处改为
u

盘的
Device Boot
)

The number of cylinders for this disk is set to 9729.

There is nothing wrong with that, but this is larger than 1024,

and could in certain setups cause problems with:

1) software that runs at boot time (e.g., old versions of LILO)

2) booting and partitioning software from other OSs

(e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): p

显示

目前
U

盘状态。

Command (m for help): d

Partition number (1-4): 4

Command (m for help): d

Partition number (1-4): 3

Command (m for help): d

Partition number (1-4): 2

Command (m for help): d

Command (m for help): p

Disk /dev/sdb: 1023 MB, 1023409152 bytes

255 heads, 63 sectors/track, 9729 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System

Command (m for help): n

Command action

l logical (5 or over)

p primary partition (1-4)

P

Partition number (1-4): 1

Command (m for help): p

显示目前的
U

盘状态。

Command (m for help): x

Expert command (m for help): m

Command action

b move beginning of data in a partition

c change number of cylinders

d print the raw data in the partition table

e list extended partitions

f fix partition order

g create an IRIX (SGI) partition table

h change number of heads

m print this menu

p print the partition table

q quit without saving changes

r return to main menu

s change number of sectors/track

v verify the partition table

w write table to disk and exit

Expert command (m for help): f

Done.

Expert command (m for help): r

Command (m for help): p

显示
U

盘当前状态。

Command (m for help): w
//

保存你所做的工作并且退出。

以上就是对
U

盘进行重新分区。把
4 part

合为一个。

这时的
U

盘还没有格式化。你需要对
U

盘进行格式化。

先卸载
u
盘

#umount /dev/sdb1

#
注意
/dev/
后面的设备要根据你的实际情况而定

格式化并建立
VFAT
文件系统

#mkfs.vfat /dev/sdb1

最后再
mount
上就成了
,
或者把
U
盘拨了再插上
,
系统可能会自动
mount
上
,
就可以用
U
盘了

这样在
pc linux

系统和
embedded linux

系统下就可以一个
U

盘对应一个设备名了。并且可以正常使用。