doesn't contain a valid partition table

[root@rac2 ~]# fdisk -l

Disk /dev/sda: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id System
/dev/sda1   *           1          13      104391   83 Linux
/dev/sda2              14         464     3622657+ 83 Linux
/dev/sda3             465         914     3614625   83 Linux
/dev/sda4             915        1044     1044225    5 Extended
/dev/sda5             915        1044     1044193+ 82 Linux swap

Disk /dev/sdb: 107 MB, 107374080 bytes
64 heads, 32 sectors/track, 102 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes

   Device Boot      Start         End      Blocks   Id System
/dev/sdb1               1          96       98288   83 Linux
/dev/sdb2              97         102        6144   83 Linux

Disk /dev/sdc: 107 MB, 107374080 bytes
64 heads, 32 sectors/track, 102 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes

Disk /dev/sdc doesn't contain a valid partition table

Disk /dev/sdd: 3221 MB, 3221225472 bytes
255 heads, 63 sectors/track, 391 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sdd doesn't contain a valid partition table
[root@rac2 ~]# fdisk /dev/sdd
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won't be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

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

Calling ioctl() to re-read partition table.
Syncing disks.
[root@rac2 ~]# partprobe
Warning: Unable to open /dev/hdc read-write (Read-only file system). /dev/hdc has been opened read-only.
[root@rac2 ~]# fdisk -l