Linux mount hard disk error "you must specify the filesystem type"

Today's virtual machine disk is used to complete, so I want to add a disk, when the mount finds the error you must specify the filesystem type. (Note: My system environment is lcentos6.3 virtual machine installed in virtualbox).

Originally because the disk has no format partition, so the following operations:

1) First check the current system situation, the newly added disk is sdb

 
 
 [root@test ~]# lsblk 
 
 NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT 
 
 sr0 11:0 1 1024M 0 rom 
 
 sda 8:0 0 8G 0 disk 
 
 ├─sda1 8:1 0 500M 0 part /boot 
 
 └─sda2 8:2 0 7.5G 0 part 
 
 ├─ VolGroup-lv_root (dm-0) 253:0 0 6.6G 0 lvm /
 
 └─VolGroup-lv_swap (dm-1) 253:1 0 992M 0 lvm [SWAP] 
 
 sdb 8:16 0 8G 0 disk 

 2) Try to mount, report error 
 
 [root@test ~]# mount /dev/sdb /disk < Br> 
 mount: you must specify the filesystem type 

 3) Format the disk
 
 [root@test ~]# mkfs.ext3 /dev/sdb 
 
 Mke2fs 1.41.12 (17-May-2010) 
 
 /dev/sdb is entire device, not just one partition! 
 
Continue anyway? (y,n) y 
 
 File System Tags = 
 
 Operating System: Linux 
 
 Block Size = 4096 (log=2) 
 
 Block Size = 4096 (log=2) < Br> 
 Stride=0 blocks, Stripe width=0 blocks 
 
 524288 inodes, 2097152 blocks 
 
 104857 blocks (5.00%) reserved for the super user 
 
 One data block=0 
 
 Maximum filesystem blocks=2147483648 
 
 64 block groups 
 
 32768 blocks per group, 32768 fragments per group 
 
 8192 inodes per Group 
 
 Superblock backups stored on blocks: 
 
 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632 
 
 
 
 Writing inode Table: Complete 
 
 Creating journal (32768 blocks): Complete 
 
 Writing superblocks and filesystem accounting information: Complete 
 
 
 
 This filesystem will Be automatically checked every 27 mounts or 
 
 180 days, whichever comes first. Use tune2fs -c or -i to override. 
 
 [root@test ~]# 

 4) Mounted successfully
 
 [root@test ~]# cd /disk/
 
 [root@test disk]# ls 
 
 Lost+found 

 5) Increase boot time 
 
 tmpfs /dev/shm tmpfs defaults 0 0 
 
 devpts /dev/pts devpts Gid=5,mode=620 0 0 
 
 sysfs /sys sysfs defaults 0 0 
 
 proc /proc proc defaults 0 0 
 
 /dev/sdb /disk ext3 defaults 0 0