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Creating a partition
Recall that the
sda device has an extra 600 MiB of unused space on it after the
sda1 partition. Let's make use of this extra space by creating a new partition on the device. First, we should take a quick look at the partition table. To do so, type the command:
sudo fdisk -l /dev/sda
sudoat the beginning of the command causes the command to be executed with the super user (root) account. Try running the
sudo. What happens? The
/dev/sdafile is crucial for system operation. It holds the enitre operating system. It would be a severe security risk if a non-privleged account could access this file.
The output of
fdisk looks like this:
Disk /dev/sda: 2 GiB, 2147483648 bytes, 4194304 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 Disklabel type: dos Disk identifier: 0x8c44efc8 Device Boot Start End Sectors Size Id Type /dev/sda1 2048 2936012 2933965 1.4G 83 Linux
This gives us some new information about our
sda disk. It confirms that it is, indeed, a 2 GiB device, and it tells us that it is comprised of 4,194,304 sectors, each of which is 512 bytes (0.5 KiB) in size. It also tells us that the first partition,
/dev/sda1 is 2,933,965 sectors in size, from sector 2,048 to sector 2,936,012.
Let's try creating a new partition after this one. Type
sudo fdisk /dev/sda. This will start up the
fdisk utility, and provides you with a prompt for a command.
p and press Enter. The
p command prints out the partition table. This is the information we already saw.
n and press Enter. This will create a new partition. You will be prompted for several pieces of information (partition type, number, etc.) For now, just press Enter for each prompt to accept the default values. Eventually you will see the following message:
Created a new partition 2 of type 'Linux' and of size 614 MiB.
To see your new partition, use the
p command again to print the partition table. The partition you just created is listed as /dev/sda2. When you are done admiring your handiwork, type
w (for write) and press Enter. This will exit the
fdiskutility reads and writes MBR-style partition tables. This is an older technology that is slowly being phased out and replaced with the GPT partitioning scheme. We'll discuss this in more detail in another course (link TBD). For now, let's stick with MBR.
fdisk informs you that the new partition isn't visible to the OS yet. You can verify this with
lsblk. Let's make it visible. Execute the following command:
sudo partprobe /dev/sda
lsblk. Do you see the new partition?