xubuntu@xubuntu:~$ sudo dd if=/dev/zero of=/dev/sda count=10000 && sync
10000+0 records in
10000+0 records out
5120000 bytes (5.1 MB, 4.9 MiB) copied, 0.48924 s, 10.5 MB/s
xubuntu@xubuntu:~$ sudo fdisk /dev/sda

Welcome to fdisk (util-linux 2.27.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0xdb6fe899.

Command (m for help): o
Created a new DOS disklabel with disk identifier 0xe3e29b35.

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.