Linux下使用fdisk命令将高容量SD卡(SDHC)格成两个分区

刚买了一个4G的TF卡，居然在我的智能山寨机coolo818上不能使用，因为coolo818最大支持2G的卡。于是，就想把高容量的SD卡格成两个2G的盘片来用。

在 Fedora 8下，将一张4G的TF卡(MicroSD),格成两个2G的分区，一个主分区，一个逻辑分区。

ps：SD卡有TF卡（现在通称MicroSD），SD卡，MiniSD卡,SDHC等多种，长的不一样；除此之外，还有一种MMC卡。

指令：fdisk
用途：观察硬盘之实体使用情形与分割硬盘用。
使用方法：
　　　　　　一、在 console 上输入 fdisk -l /dev/sdb ，观察硬盘之实体使用情形。
　　　　　　二、在 console 上输入 fdisk /dev/sdb，可进入分割硬盘模式。
　　　　　　　　1. 输入 m 显示所有命令列示。
　　　　　　　　2. 输入 p 显示硬盘分割情形。
　　　　　　　　3. 输入 a 设定硬盘启动区。
　　　　　　　　4. 输入 n 设定新的硬盘分割区。  
　　　　    　　　4.1. 输入 e 硬盘为[延伸]分割区(extend)。
　　　　　　　　　4.2. 输入 p 硬盘为[主要]分割区(primary)。
　　　　　　　　5. 输入 t 改变硬盘分割区属性。
　　　　　　　　6. 输入 d 删除硬盘分割区属性。
　　　　　　　　7. 输入 q 结束不存入硬盘分割区属性。
　　　　　　　　8. 输入 w 结束并写入硬盘分割区属性。

[root@localhost ~]# fdisk /dev/sdb      #插入读卡器，在我电脑上显示是sdb,以下黑字为键入部分

The number of cylinders for this disk is set to 189513.
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): m       #help
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                  #查看
Disk /dev/sdb: 4075 MB, 4075290624 bytes
7 heads, 6 sectors/track, 189513 cylinders
Units = cylinders of 42 * 512 = 21504 bytes
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id System
/dev/sdb1               1       93007     1953144    c W95 FAT32 (LBA)
/dev/sdb2           93008      189513     2026626    f W95 Ext'd (LBA)
/dev/sdb5           93008      189513     2026623    c W95 FAT32 (LBA)
Command (m for help): d
Partition number (1-5): 1 #删除1分区，因为之前我已经分成两个区了，所以现在演示时显示有两个分区，总之，先删掉

Command (m for help): d
Partition number (1-5): 2 #删除2分区

Command (m for help): d
No partition is defined yet!

Command (m for help): p

Disk /dev/sdb: 4075 MB, 4075290624 bytes
7 heads, 6 sectors/track, 189513 cylinders
Units = cylinders of 42 * 512 = 21504 bytes
Disk identifier: 0x00000000

#以上为删除原有的分区

Device Boot      Start         End      Blocks   Id System
Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-189513, default 1):
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-189513, default 189513): +2048M

Command (m for help): t
Selected partition 1
Hex code (type L to list codes): L

0 Empty           1e Hidden W95 FAT1 80 Old Minix       be Solaris boot  
1 FAT12           24 NEC DOS         81 Minix / old Lin bf Solaris       
2 XENIX root      39 Plan 9          82 Linux swap / So c1 DRDOS/sec (FAT-
3 XENIX usr       3c PartitionMagic 83 Linux           c4 DRDOS/sec (FAT-
4 FAT16 <32M      40 Venix 80286     84 OS/2 hidden C: c6 DRDOS/sec (FAT-
5 Extended        41 PPC PReP Boot   85 Linux extended c7 Syrinx        
6 FAT16           42 SFS             86 NTFS volume set da Non-FS data   
7 HPFS/NTFS       4d QNX4.x          87 NTFS volume set db CP/M / CTOS / .
8 AIX             4e QNX4.x 2nd part 88 Linux plaintext de Dell Utility  
9 AIX bootable    4f QNX4.x 3rd part 8e Linux LVM       df BootIt        
a OS/2 Boot Manag 50 OnTrack DM      93 Amoeba          e1 DOS access    
b W95 FAT32       51 OnTrack DM6 Aux 94 Amoeba BBT      e3 DOS R/O       
c W95 FAT32 (LBA) 52 CP/M            9f BSD/OS          e4 SpeedStor     
e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a0 IBM Thinkpad hi eb BeOS fs       
f W95 Ext'd (LBA) 54 OnTrackDM6      a5 FreeBSD         ee EFI GPT       
10 OPUS            55 EZ-Drive        a6 OpenBSD         ef EFI (FAT-12/16/
11 Hidden FAT12    56 Golden Bow      a7 NeXTSTEP        f0 Linux/PA-RISC b
12 Compaq diagnost 5c Priam Edisk     a8 Darwin UFS      f1 SpeedStor     
14 Hidden FAT16 <3 61 SpeedStor       a9 NetBSD          f4 SpeedStor     
16 Hidden FAT16    63 GNU HURD or Sys ab Darwin boot     f2 DOS secondary
17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs         fd Linux raid auto
18 AST SmartSleep 65 Novell Netware b8 BSDI swap       fe LANstep       
1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid ff BBT           
1c Hidden W95 FAT3 75 PC/IX     
Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-189513, default 1):
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-189513, default 189513): +2048M

Command (m for help): t
Selected partition 1
Hex code (type L to list codes): L

0 Empty           1e Hidden W95 FAT1 80 Old Minix       be Solaris boot  
1 FAT12           24 NEC DOS         81 Minix / old Lin bf Solaris       
2 XENIX root      39 Plan 9          82 Linux swap / So c1 DRDOS/sec (FAT-
3 XENIX usr       3c PartitionMagic 83 Linux           c4 DRDOS/sec (FAT-
4 FAT16 <32M      40 Venix 80286     84 OS/2 hidden C: c6 DRDOS/sec (FAT-
5 Extended        41 PPC PReP Boot   85 Linux extended c7 Syrinx        
6 FAT16           42 SFS             86 NTFS volume set da Non-FS data   
7 HPFS/NTFS       4d QNX4.x          87 NTFS volume set db CP/M / CTOS / .
8 AIX             4e QNX4.x 2nd part 88 Linux plaintext de Dell Utility  
9 AIX bootable    4f QNX4.x 3rd part 8e Linux LVM       df BootIt        
a OS/2 Boot Manag 50 OnTrack DM      93 Amoeba          e1 DOS access    
b W95 FAT32       51 OnTrack DM6 Aux 94 Amoeba BBT      e3 DOS R/O       
c W95 FAT32 (LBA) 52 CP/M            9f BSD/OS          e4 SpeedStor     
e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a0 IBM Thinkpad hi eb BeOS fs       
f W95 Ext'd (LBA) 54 OnTrackDM6      a5 FreeBSD         ee EFI GPT       
10 OPUS            55 EZ-Drive        a6 OpenBSD         ef EFI (FAT-12/16/
11 Hidden FAT12    56 Golden Bow      a7 NeXTSTEP        f0 Linux/PA-RISC b
12 Compaq diagnost 5c Priam Edisk     a8 Darwin UFS      f1 SpeedStor     
14 Hidden FAT16 <3 61 SpeedStor       a9 NetBSD          f4 SpeedStor     
16 Hidden FAT16    63 GNU HURD or Sys ab Darwin boot     f2 DOS secondary
17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs         fd Linux raid auto
18 AST SmartSleep 65 Novell Netware b8 BSDI swap       fe LANstep       
1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid ff BBT           
1c Hidden W95 FAT3 75 PC/IX   

Hex code (type L to list codes): c
Changed system type of partition 1 to c (W95 FAT32 (LBA))

#以上为建2G的主分区，W95 FAT32 (LBA)类型

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
e
Partition number (1-4): 2
First cylinder (95240-189513, default 95240):
Using default value 95240
Last cylinder or +size or +sizeM or +sizeK (95240-189513, default 189513):
Using default value 189513

Command (m for help): t
Partition number (1-5): 2
Hex code (type L to list codes): f
Changed system type of partition 2 to f (W95 Ext'd (LBA))

#以上为创建扩展分区，类型为W95 Ext'd (LBA)

Command (m for help): n
Command action
   l   logical (5 or over)
   p   primary partition (1-4)
l
First cylinder (95240-189513, default 95240):
Using default value 95240
Last cylinder or +size or +sizeM or +sizeK (95240-189513, default 189513):
Using default value 189513

Command (m for help): t
Partition number (1-5): 5
Hex code (type L to list codes): c
Changed system type of partition 5 to c (W95 FAT32 (LBA))

#以上为创建逻辑驱动器在扩展分区上，类型为W95 FAT32 (LBA)

Command (m for help): p

Disk /dev/sdb: 4075 MB, 4075290624 bytes
7 heads, 6 sectors/track, 189513 cylinders
Units = cylinders of 42 * 512 = 21504 bytes
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id System
/dev/sdb1               1       95239     2000016    c W95 FAT32 (LBA)
/dev/sdb2           95240      189513     1979754    f W95 Ext'd (LBA)
/dev/sdb5           95240      189513     1979751    c W95 FAT32 (LBA)

Command (m for help): w   #保存
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: 设备或资源忙.
The kernel still uses the old table.
The new table will be used at the next reboot.

WARNING: If you have created or modified any DOS 6.x
partitions, please see the fdisk manual page for additional
information.
Syncing disks.
[root@localhost ~]# find /dev/sdb*
/dev/sdb
/dev/sdb1
/dev/sdb2
/dev/sdb5
mkfs.vfat: /dev/sdb1 contains a mounted file system.
[root@localhost ~]# mkfs.vfat /dev/sdb1
mkfs.vfat 2.11 (12 Mar 2005)
[root@localhost ~]# mkfs.vfat /dev/sdb5   
mkfs.vfat 2.11 (12 Mar 2005)
[root@localhost ~]# cd /mnt
[root@localhost mnt]# mkdir sd1 sd5
[root@localhost mnt]# mount /dev/sdb1 sd1
[root@localhost mnt]# mount /dev/sdb5 sd5     

----------------------------------------------------------

#一下是两个2G的分区合并成一个4G的，方法类似，不在累述。

[root@localhost ~]# fdisk /dev/sdb

The number of cylinders for this disk is set to 189513.
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): 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/sdb: 4075 MB, 4075290624 bytes
7 heads, 6 sectors/track, 189513 cylinders
Units = cylinders of 42 * 512 = 21504 bytes
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id System
/dev/sdb1               1       95239     2000016    c W95 FAT32 (LBA)
/dev/sdb2           95240      189513     1979754    f W95 Ext'd (LBA)
/dev/sdb5           95240      189513     1979751    c W95 FAT32 (LBA)

Command (m for help): d
Partition number (1-5): 1

Command (m for help): d
Partition number (1-5): 2

Command (m for help): d
No partition is defined yet!

Command (m for help): p

Disk /dev/sdb: 4075 MB, 4075290624 bytes
7 heads, 6 sectors/track, 189513 cylinders
Units = cylinders of 42 * 512 = 21504 bytes
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id System

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p

Partition number (1-4): 1
First cylinder (1-189513, default 1):
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-189513, default 189513):
Using default value 189513

Command (m for help): t
Selected partition 1
Hex code (type L to list codes): c
Changed system type of partition 1 to c (W95 FAT32 (LBA))

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: 设备或资源忙.
The kernel still uses the old table.
The new table will be used at the next reboot.

WARNING: If you have created or modified any DOS 6.x
partitions, please see the fdisk manual page for additional
information.
Syncing disks.
[root@localhost ~]# mkfs.vfat /dev/sdb1
mkfs.vfat 2.11 (12 Mar 2005)