前段时间用SD卡刻了用一个Linux系统（存储系统），插在windows下显示只有32MB（原卡16GB的）。好了，问题来了，其他的空间去哪里了呢？
1、如何释放其他未使用的空间？
2、如何重新找回所有空间作为他用呢？
第一个问题的解决办法：
参考我的另一篇文章：《树莓派Raspberry Pi 16G SD卡刷系统时默认空间扩容》
使用gparted图形化工具进行分区扩容。
地址：http://thinkpig007.blog.51cto.com/971471/1334196
第二个问题的解决办法：
当你将此sd插入windows系统下打算格式化，用做他用。可是很悲剧，你右键SD属性，只看到可用空间为32MB，天呐？16GB的空间怎么就剩这么点了呢？你试着想使用windows下的格式化来解决问题，但是当你右键格式化后，可用空间依旧只有32MB，怎么办呢？
这是因为在写入存储系统的时候，硬件将SD重新分区了，你在windows下格式化和看到只是存储系统的一个分区。要把其他空间找回来就需要重新分区（一般SD就分一个分区）。
有两种解决办法：
（1）使用windows PE里面的磁盘分区工具或者单独使用磁盘分区工具
找到SD，将所有分区删除（注意是SD，不要搞错了哦）
（2）使用linux下的fdisk工具来进行重新分区
我的操作过程：
查看当前系统的挂载的分区情况，看到最后的SD分区
root@bt:~# mount
/dev/sda1 on / type ext4 (rw,errors=remount-ro)
proc on /proc type proc (rw,noexec,nosuid,nodev)
none on /sys type sysfs (rw,noexec,nosuid,nodev)
none on /sys/fs/fuse/connections type fusectl (rw)
none on /sys/kernel/debug type debugfs (rw)
none on /sys/kernel/security type securityfs (rw)
none on /dev type devtmpfs (rw,mode=0755)
none on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)
none on /dev/shm type tmpfs (rw,nosuid,nodev)
none on /var/run type tmpfs (rw,nosuid,mode=0755)
none on /var/lock type tmpfs (rw,noexec,nosuid,nodev)
none on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
vmware-vmblock on /var/run/vmblock-fuse type fuse.vmware-vmblock
(rw,nosuid,nodev,default_permissions,allow_other)
/dev/sdb1 on /media/NB_5024_X64 type fuseblk
(rw,nosuid,nodev,allow_other,blksize=4096,default_permissions)
将SD挂载卸载
root@bt:~# umount /dev/sdb1
对SD的分区进行删除
root@bt:~# fdisk /dev/sdb1
WARNING: DOS-compatible mode is deprecated. It's strongly
recommended to
switch off the mode (command 'c') and change display
units to
sectors (command 'u').
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): p
Disk /dev/sdb1: 32 MB, 32868864 bytes
255 heads, 63 sectors/track, 3 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x73736572
This doesn't look like a partition table
Probably you selected the wrong device.
Device Boot Start End Blocks Id System
/dev/sdb1p1 119529 232583 908105142 72 Unknown
Partition 1 has different physical/logical beginnings (non-
Linux?):
phys=(80, 13, 10) logical=(119528, 74, 3)
Partition 1 has different physical/logical endings:
phys=(371, 101, 51) logical=(232582, 38, 44)
Partition 1 does not end on cylinder boundary.
/dev/sdb1p2 ? 120513 242122 976826554 6c Unknown
Partition 2 has different physical/logical beginnings (non-
Linux?):
phys=(357, 43, 4) logical=(120512, 46, 15)
Partition 2 has different physical/logical endings:
phys=(367, 32, 52) logical=(242121, 118, 1)
Partition 2 does not end on cylinder boundary.
/dev/sdb1p3 ? 1 1 0 0 Empty
Partition 3 has different physical/logical beginnings (non-
Linux?):
phys=(0, 10, 0) logical=(0, 0, 1)
Partition 3 has different physical/logical endings:
phys=(0, 0, 0) logical=(267349, 89, 4)
Partition 3 does not end on cylinder boundary.
/dev/sdb1p4 1726 1726 223+ 0 Empty
Partition 4 has different physical/logical beginnings (non-
Linux?):
phys=(0, 0, 0) logical=(1725, 158, 44)
Partition 4 has different physical/logical endings:
phys=(0, 0, 0) logical=(1725, 165, 49)
Partition 4 does not end on cylinder boundary.
Command (m for help): d
Command (m for help): p
Disk /dev/sdb1: 32 MB, 32868864 bytes
255 heads, 63 sectors/track, 3 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x73736572
Device Boot Start End Blocks Id System
Command (m for help): w
删除完sdb1后，w保存
同样再来对sdb真个设备进行分区删除
root@bt:~# fdisk /dev/sdb——》d——》w,d删除分区，w保存操作退出fdisk
再来看，sdb设备大小，且没有其他分区。
root@bt:~# fdisk -l
Disk /dev/sda: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000025ee
Device Boot Start End Blocks Id System
/dev/sda1 * 1 12518 100548608 83 Linux
/dev/sda2 12518 13055 4305921 5 Extended
/dev/sda5 12518 13055 4305920 82 Linux
swap / Solaris
Disk /dev/sdb: 15.9 GB, 15931539456 bytes
64 heads, 32 sectors/track, 15193 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x4f9ae4a3
Device Boot Start End Blocks Id System
root@bt:~#
OK搞定，将SD从Linux系统退出，放到windows下格式化为NTFS，可以看到有14.8GB的空间可用。