mount: you must specify the filesystem type

1: $sudo fdisk -ls

Disk /dev/sdb: 8036 MB, 8036286464 bytes
248 heads, 62 sectors/track, 1020 cylinders, total 15695872 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: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *        2048      133119       65536    c  W95 FAT32 (LBA)
/dev/sdb2          133120    15695871     7781376   83  Linux

2:$sudo mount /dev/sdb1 /tmp/mmc1   

=>OK;

   sudo mount /dev/sdb2 /tmp/mmc2   

=>mount: you must specify the filesystem type

3:$sudo mkfs.ext3 /dev/sdb2                

   =>OK;

4:$ sudo mount /dev/sdb2 /tmp/mmc2

=>mount: you must specify the filesystem type

5:$sudo mount -t ext3 /dev/sdb2 /tmp/mmc2

=>mount: wrong fs type, bad option, bad superblock on /dev/sdb2,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

6:$dmesg | tail

=>[  534.496845] sd 4:0:0:0: [sdb] Assuming drive cache: write through
[  534.500641]  sdb: sdb1 sdb2
[  534.521625] sd 4:0:0:0: [sdb] No Caching mode page present
[  534.521630] sd 4:0:0:0: [sdb] Assuming drive cache: write through
[  534.521633] sd 4:0:0:0: [sdb] Attached SCSI removable disk
[  604.743249] EXT3-fs (sdb2): error: can't find ext3 filesystem on dev sdb2.
[  604.791308] EXT4-fs (sdb2): VFS: Can't find ext4 filesystem
[  604.862243] FAT-fs (sdb2): bogus number of reserved sectors
[  604.862248] FAT-fs (sdb2): Can't find a valid FAT filesystem
[  622.050513] EXT3-fs (sdb2): error: can't find ext3 filesystem on dev sdb2.

這是為什麼呢?

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剛剛：我刪除了原有的分區:建立了4個分區；

1：$sudo fdisk -ls /dev/sdc

=> Disk /dev/sdc: 8036 MB, 8036286464 bytes
248 heads, 62 sectors/track, 1020 cylinders, total 15695872 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: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1   *        2048      133119       65536    c  W95 FAT32 (LBA)
/dev/sdc2          133120    15695871     7781376    5  Extended
/dev/sdc5          135168     2232319     1048576   83  Linux
/dev/sdc6         2234368    15695871     6730752   83  Linux

2：$sudo mount /dev/sdc1 /tmp/mmc1       => OK;

      $sudo mount /dev/sdc5 /tmp/mmc2       => OK；

     $sudo mount /dev/sdc6 /tmp/mmc3       =>mount: you must specify the filesystem type;

  我已經：mkfs.ext3 /dev/sdc6……

 好現象是：我把android啟迪程式：拷貝到：sdc1裡，把rootfs解壓到：sdc5；上電pandaboard可以啟動了……串口輸出啟動資訊了……雖然還不能進入登陸介面……