Windows Disk Management¶

Exercise windows-disk-management-annex.pdf · PDF

Open This PC on any Windows computer. You see C:. Maybe D:. Have you ever wondered why it starts at C? Where are A and B?

The answer is a story from 1983 — the same year MBR was born. And it hides a bigger lesson: a disk does not know which operating system is looking at it. The GPT table you built on Linux is exactly the same table Windows reads. Only the words change. Today you learn the Windows words, first with the mouse and then with the keyboard.

What you will learn

Translate the Linux words into Windows: disk, partition, volume, drive letter
Initialize a new disk, and create, shrink and re-letter volumes with Disk Management
Do the same job from the command line with diskpart: list, select, create, format, assign
Explain the focus of diskpart and why clean is the most dangerous word of the day
Why D: is not "the second disk"

The same disk, other words¶

Think of it as translation: the disk is the same building, described in two languages. Here is the dictionary:

Linux	Windows
`/dev/vda`, `/dev/vdb`: disks have names	Disk 0, Disk 1: disks have numbers
Partition `/dev/vdb1`	Partition 1 of Disk 1
A partition with a file system	A volume
It appears as a directory in the one tree (mounting)	It gets a drive letter and its own tree: `T:\`
`lsblk`, `fdisk -l`	The map in Disk Management, `list disk`
`fdisk`, `parted`	Disk Management (mouse), diskpart (keyboard)

A volume is a partition with a file system that Windows can use. A drive letter is the name Windows gives a volume: C:, D:, T:.

Careful: D: is not the second disk

A letter is given to a volume, not to a disk. One disk can hold C: and D:. A DVD drive or a USB stick also gets a letter.

Why `C:`?¶

In the first IBM PCs, the two drives were floppy disk drives: A: and B:. In March 1983 the IBM PC XT arrived with a 10 MB hard disk inside, and PC DOS 2.0 gave it the next free letter: C:. Forty-three years later the floppies are gone, and the letter is still there. The MBR partition table from Partitions: MBR and GPT was born in that same DOS 2.0.

Add a disk to `win11`¶

With win11 shut down, the same click path as for deb-lab: View → Details → Add Hardware → Storage → Create a disk image for the virtual machine: 5 GiB → Bus type: SATA → Finish. Start win11 and log in.

Why SATA and not VirtIO this time? Windows understands SATA with no extra driver. A VirtIO disk is only seen if the VirtIO storage driver was installed with Windows.

Disk 0 is Windows itself

Our disk is the 5 GB one. Same ritual as on Linux: read the size before every click. Never touch Disk 0.

Disk Management: with the mouse¶

Open it as administrator: Start → type Create and format hard disk partitions → right-click → Run as administrator → Yes. At the bottom you see the map:

Disk 0: 64 GB, with the EFI System Partition, C: and a recovery partition.
Disk 1: about 5 GB, Not Initialized or Offline, all Unallocated.

The steps, in order:

Step	Where you click	What happens
1 · Initialize	Right-click the box Disk 1 (on the left) → Initialize Disk → GPT	Windows writes an empty partition table. Disk 1 becomes Online.
2 · New volume	Right-click the Unallocated bar → New Simple Volume	A wizard: size 2000 MB → letter T → NTFS, label `DEV`, quick format
3 · Another one	The same, on the space that is left	1500 MB → letter S → NTFS, label `DESIGN`
4 · Check	File Explorer → This PC	`DEV (T:)` and `DESIGN (S:)` appear
5 · Re-letter	Right-click `DESIGN (S:)` → Change Drive Letter and Paths → Change → P	Windows warns that programs relying on the letter may stop working. `DESIGN` is now `P:`.
6 · Shrink	Right-click `DEV (T:)` → Shrink Volume → 500 MB	`DEV` is now about 1500 MB, with 500 MB Unallocated right after it. The files in `T:` are still there.

The wizard asks for a file system and offers NTFS. Accept it for now: choosing a file system is the topic of File systems.

Careful: initializing is not formatting

Initializing writes an empty partition table (GPT or MBR) — the walls plan. Formatting comes later, once per volume, and puts a file system inside. And shrinking does not delete files: Windows moves them out of the way first.

When something does not work¶

Problem	Likely cause
Disk 1 does not appear	The disk was added while Windows was running, or as VirtIO. Shut down, check the bus is SATA, start again. In the tool: Action → Rescan Disks.
Everything is greyed out	The tool is not running as administrator, or you right-clicked the wrong place: the box on the left has Initialize; the bar on the right has New Simple Volume.
The letter you want is not in the list	It is taken (a DVD drive, a network drive). Any free letter will do.

diskpart: with the keyboard¶

Everything you just clicked can be typed. diskpart is the fdisk of Windows — the tool a script, or a broken Windows with no desktop, will ask you for. Open Start → type cmd → right-click → Run as administrator, then type diskpart. The prompt becomes DISKPART>.

The focus¶

diskpart has one new idea:

The focus is the disk, partition or volume that diskpart's next commands will act on. You set it with select.

DISKPART> list disk          what is there?
DISKPART> select disk 1      point at one: it gets the FOCUS
DISKPART> list disk          the disk with focus has a * in front

So the rule is: list, select, list again, look for the asterisk. Only then act. Like parted, diskpart writes at once.

Never type clean without a reason

clean erases the partition table of the disk with the focus, with no question and no undo. With the focus on Disk 0, it destroys the Windows installation. You do not need it today.

A third volume, keyboard only¶

Make EXCHANGE (X:), 500 MB, without the mouse:

DISKPART> list disk
DISKPART> select disk 1
DISKPART> list disk
DISKPART> list partition
DISKPART> create partition primary size=500
DISKPART> format fs=ntfs label=EXCHANGE quick
DISKPART> assign letter=X
DISKPART> list volume
DISKPART> exit

Command	Does
`list disk` / `list partition` / `list volume`	Shows what is there; `*` marks the focus
`select disk 1`	Puts the focus on Disk 1
`create partition primary size=500`	A new partition; `size` is in megabytes
`format fs=ntfs label=EXCHANGE quick`	Writes an NTFS file system. Without `quick`, it checks the whole volume and takes much longer.
`assign letter=X`	Gives the volume a drive letter

Two things to notice:

After create, the focus moves to the new partition by itself. That is why format and assign need no new select.
list partition usually shows one partition more than you made: a small Reserved one that Windows adds when it initializes a GPT disk. Leave it alone.

If you forget select, diskpart answers There is no disk selected. The error is the answer.

flowchart LR
    L["<b>list disk</b><br>what is there?"] --> S["<b>select disk 1</b><br>set the focus"]
    S --> L2["<b>list disk</b><br>find the *"]
    L2 --> A["<b>create · format · assign</b><br>act on the focus"]
    A --> V["<b>list volume</b><br>check the result"]

Key takeaways¶

The disk and its GPT table are the same for every OS; only the words change: Disk 0/1, partition, volume, drive letter.
Letters belong to volumes, not disks. C: comes from 1983: A: and B: were the floppy drives of the IBM PC.
Disk Management: initialize (write a table), New Simple Volume, Change Drive Letter and Paths, Shrink Volume.
diskpart: list, select, list again, look for the * — the focus — then create, format, assign.
clean wipes the table of the disk with the focus, with no undo. Disk 0 is Windows: never touch it.

Quick check¶

1. A new disk shows up as Not Initialized. What is the first thing to do?

Format it as NTFS
Give it a partition table such as GPT
Give it a drive letter
Shrink it

Initializing writes an empty partition table. Only after that can you create partitions, format them and give them letters.

2. In Windows, what is a partition with a file system and a drive letter called?

A disk
A folder
A sector
A volume

Windows calls a usable partition a volume. On Linux the same thing would be a partition with a file system, mounted on a directory.

3. In diskpart, after select disk 1, what does the asterisk in list disk mark?

The disk the next commands will act on
The disk where Windows is installed
A disk with errors
The biggest disk

The asterisk marks the focus. Every command after select acts on it — which is why you list again and check the * before acting.

4. Why does Windows start at C:?

C stands for "computer"
A: and B: are hidden system volumes
A: and B: were the floppy disk drives
Microsoft chose it for Windows 11

The first IBM PCs had two floppy drives, A: and B:. The IBM PC XT of 1983 put a hard disk inside, and PC DOS 2.0 gave it the next letter: C:.

5. Why did format and assign work without a new select after create partition?

create moves the focus to the new partition by itself
format and assign always act on every partition
diskpart remembers the last letter you typed
The focus always stays on the whole disk

After create partition, the focus jumps to the partition just created, so the next commands act on it. With no focus at all, diskpart answers There is no disk selected.

6. What happens to the files in T: when you shrink the volume by 500 MB?

They stay; Windows moves them out of the way first
They are deleted to make room
They are moved to a new volume U:
They are copied into the unallocated space

Shrink Volume first moves data away from the end of the volume, then gives that space back as Unallocated. Files it cannot move set the limit of how much you can shrink.

7. Aina's laptop has one SSD, and File Explorer shows C: and D:. Select the two that are true.

One disk can hold several volumes, each with its own letter
Disk Management would show both volumes on Disk 0
The laptop must have two physical disks
D: must be a DVD drive

Letters belong to volumes, not disks. One SSD cut into two partitions with file systems gives two volumes: C: and D:, both on Disk 0.

On both systems a volume is exactly as big as its partition. What happens when the design room fills up? Next: make it bigger without closing the door, in LVM and RAID.