An essential step in preparing a storage medium, partitioning has advantages in separating the system from the data on a computer. Here is what you need to know to partition a hard drive or SSD.
Even if you are not aware of it, all the storage media that you use every day on your computer (hard drives, SSDs, USB drives, memory cards) are partitioned. Without this essential operation, no formatting, and therefore no storage! It is in fact thanks to partitioning that we create “volumes” – or “drives” according to the terminology of the operating system used – which are used to permanently store data (files or folders). But since partitioning and formatting is most often done at the factory, by the manufacturer of the drive, SSD, key or computer, these preparatory technical operations remain virtually invisible to the average user who simply browses through the volumes at its disposal for storing or reading files. The notion of partitioning is even so transparent that many ignore that the disks installed as standard in their PC or Mac host “invisible” partitions intended for the operating system (Windows or macOS). Note also that the very principle of partitioning is independent of the operating system: it is common to Windows, macOS and all distributions of Linux. The purpose of this practical sheet is to take stock of the issue.
What is a score?
As its name suggests, a partition is a “part” of a storage medium: it is also sometimes referred to as a “section” or “region”, or even a “logical” unit, as opposed to a “physical” unit. “, which corresponds to the material medium, that is to say to the medium itself. Thus, a hard drive or an SSD can be virtually “cut” into several parts or into one, depending on usage and needs. These parts, or partitions, are independent from the point of view of the operating system – and therefore of the user – even if they are physically located on the same medium. Hence the famous distinction between logical unit and physical unit. To take an image, it’s like dividing a space – a place like a warehouse, a house or an apartment – into several rooms separated by partitions. Everything is well stored in the same physical space, but in different zones.
In the case of a Windows PC, for example, a 1TB drive or SSD can perfectly be divided into three partitions: one of 500 GB, one of 300 GB and one of 200 GB (the numbers are intentionally rounded to simplify the subject). Each partition then behaves like an independent disk from the other two, even if they are all located on a single disk or SSD. Each is also displayed with its own drive or volume letter (: C,: D,: E or other). But we can also decide to use it “in one piece”, with a single partition taking advantage of all the storage space physically available (ie 1 TB in our example).
However, be careful, it is not enough to partition a storage medium for its partitions to be usable. Because once created, you still have to format them by assigning them a file system: FAT32, exFAT, NTFS, ext4, etc. It is only after this formatting that the partitions become usable for writing and reading data. Note that the choice of a file system is made for each partition independently of the others. It is quite possible, on the same disk, to have one partition in exFAT, another in NTFS and another in ext4, for example. It all depends on the intended use for each partition. To learn more about this very rich subject, see our practical sheet.
Finally, it should be noted that, regardless of their format, not all partitions have the same status. Some, called main or primary, are designed to accommodate an operating system, while others have more general or more specific uses. In addition, some partitions are visible and usable “normally”, via Windows Explorer or macOS Finder, for example, while others are invisible, or at least hidden, because reserved for the operating system – but it can be accessed in specific cases or with dedicated tools. Thus, when we install Windows 10 on the disk of a PC, the system automatically creates four partitions: a visible primary partition System, for Window; a hidden EFI partition (EFI System Partition or ESP) which contains files intended for UEFI, the firmware or firmware that manages the motherboard and the basic functions of the computer; a Microsoft Reserved Partition (MSR); and a hidden Recovery partition (Windows Recovery Environment or WinRE, Windows Recovery Environment) which is used to troubleshoot the PC in the event of a big problem.
Why partition a disk?
But what is the point of dividing a storage space into several parts? Isn’t it easier and more convenient to use a “one-piece” drive or SSD? Well no ! It is useful and even essential to divide certain disks into several parts, in particular in the case of disks intended to accommodate an operating system. It is not by chance that Windows and macOS automatically partition the disks on which they are installed, without asking anything, for their own needs!
Because the interest of partitioning, it is precisely to separate data to put them in independent sections, and even “waterproof”. Partitioning is therefore mandatory when you want to use several operating systems on the same computer with a single disk (Windows and Linux, Windows and macOS, or even different versions of Windows). But even when using a single system, it is strongly advised to partition the primary drive of a computer. The idea is simple: partitioning separates the operating system from personal files. Of course, the computer will not go faster like this, especially since everything is located on the same physical medium. The advantage of this “logical” separation is that in case of a big problem, you can completely empty and even reformat the system partition without touching the personal data stored on the other partition. Which is not always feasible when everything is on the same partition. This is why experts always prefer to divide the system and the data of the different partitions (called for example SYSTEM and DATA), when they have only one disk, even when it is large. The clean reinstallation of a system is then at the same time simpler, faster and more secure.
In the case of secondary disks, which do not contain an operating system, and in particular external disks, partitioning is not essential. But it is not prohibited either, for example to separate volumes according to their content, to dedicate a unit to automatic backup, or to use different file systems, during formatting, and thus ensure compatibility with several devices or operating systems.
How to partition a disk with Windows?
With a Windows PC, there are several ways to partition a storage medium (hard drive or SSDà and, more generally, to manage partitions (creation, resizing, deletion). As these operations are quite technical – and therefore delicate , not to say dangerous – they are not carried out directly in Windows Explorer, but with specific tools.
- The first, the simplest, is the tool Disk management Windows which can be accessed by right-clicking on the start menu. It offers many functions with a fairly clear graphical presentation, menus, dialog boxes, etc. To learn more about the possible manipulations, see our practical sheet.
- The second, much more complex, is the utility DiskPart, from Microsoft. Much more powerful, it can perform more sophisticated and delicate operations, even on disks that Windows does not recognize. But it is austere because everything is done in an old-fashioned interface, in text mode, using commands to type… To know everything about this tool, see our practical sheet.
- The third solution is to turn to specialized utilities that are not offered by Microsoft but by third-party vendors. There are many, some free, such as EaseUS Partition Master Free, AOMEI Partition Assistant Standard, Partition Manager, Active Partition Manager or Partition Wizard Home Edition, others for a fee, such as Partition Find & Mount, Paragon Partition Manager or O&O Partition Manager Pro.
Whatever solution you choose, you must be aware that partitioning is a sensitive operation intended for “informed” users.
How to partition a drive on Mac?
On Mac, everything related to formatting and partitioning is done with a tool that comes free with macOS, the aptly named Disk Utility, which can be used with internal media (hard drive or SSD) as well as with storage devices. external storage. As is often the case with software from Apple, the interface remains user-friendly even for fairly complex operations. To learn more about this tool and its functions, see our practical sheet. In addition, as for Windows, it is possible to use third-party software from specialist vendors, such as Hard Disk Manager for Mac from Paragon or iPartition from Coriolis System.