Windows still uses drive letters from the 1980s, and Linux's single file tree shows what we could have had

Published Nov 2, 2026, 9:00 AM EST After a 7-year corporate stint, Tanveer found his love for writing and tech too much to resist. An MBA in Marketing and the owner of a PC building business, he writes on PC hardware, technology, and Windows. When not scouring the web for ideas, he can be found building PCs, watching anime, or playing Smash Karts on his RTX 3080 (sigh). Anyone who has ever used a Windows PC is intimately familiar with the drive letter system used to organize data. For decades, Windows users have used independent drives that are top-level entities to find and refer to a particular file or folder. This convention has been in the mainstream since the 1970s, and with Microsoft's MS-DOS launch in 1981, the stage was set for it to become an enduring part of Windows. However, it didn't have to be this way. After all, there were many early computers that used numbers instead of letters, such as the TRS-80 from Tandy Corporation, which used "Drive 0" and "Drive 1" notations. Unix-like operating systems like macOS and Linux famously use a unified directory tree where drives are mounted as folders. Instead of every drive being a separate file tree, everything flows from a single root directory. A 50-year-old OS popularized drive letters, and MS-DOS made it permanent It's hard to think about a time without drive letters The first widely used operating system that had a drive letter hierarchy was CP/M (Control Program for Microcomputers). This was the first popular OS for microcomputers, created in 1974 for 8-bit machines. When the IBM PC era kicked off in 1981, CP/M was displaced by MS-DOS as the industry moved to 16-bit machines. Microsoft had purchased 86-DOS and rebranded it to PC DOS and MS-DOS, intended for use in IBM and IBM-compatible PCs, respectively. Since floppy drives were integral to early PC architecture, the hardware as well as the BIOS expected up to two floppy drives. The 1980s had firmly cemented the drive letters A: and B: as identifiers for these drives. The PCs sold in the 80s went from having two 5.25-inch floppy drives to a 5.25-inch and a 3.5-inch drive existing as A: and B: drives. The IBM PC XT in 1983 was the first IBM computer to include an internal hard drive as standard. Since the drive letters A: and B: were already taken, the hard drive was assigned the letter C:, and the rest is history. For quite a few years, operating systems needed to support both floppy drives and hard drives. Even top-of-the-line PCs of the time shipped with at least one floppy drive installed. Even though hard drives became the default storage destination going forward, the A:, B:, and C: nomenclature persisted. Developers and users needed a standardized approach to refer to the computer's primary storage disk, so with MS-DOS 5.0 (1991), the letter C: was reserved for the primary hard drive, even if more than two floppy drives were present on the system. CD-ROM and DVD-ROM drives took the subsequent letters, i.e., D: and E: by default. Windows still uses the same convention for compatibility There's little motivation to break tradition It's natural to wonder why Microsoft didn't switch to A: and B: for the primary and secondary drives, respectively, once floppy drives went extinct. However, most operating systems don't work like that. They need to account for backwards compatibility, decades of convention, and the simple need to avoid breaking software. While it's true that Microsoft wants modern versions of Windows to support floppy drives on the hardware level, the bigger reason not to mess up tradition is software compatibility. Applications assume that your primary storage drive is C:, so all installations, configurations, and system files are built with that in mind. Whether it was the older DOS ecosystem or the evolving Windows world, changing the defaults would unnecessarily break compatibility with old and new software. For decades, people have learned that C: is the primary hard drive, so even after floppy drives stopped appearing on home PCs, the convention persisted. There's just no reason to change it — Windows isn't missing out on a lot by maintaining the status quo. Even if you try to assign A: or B: to your boot drive, Windows won't allow it since the OS is designed to treat those two drive letters in a different way. Linux does it differently, and it's better in some ways Compartmentalization is the name of the game As I mentioned before, Linux took a different approach to organizing the filesystem. Unlike designating each drive as its own family tree, Linux has a unified directory tree flowing outward (or downward) to the entire filesystem. Since it's a Unix-like OS, it mounts drives as separate folders, such as /dev/sda, /dev/sdb, and so on. Linux users are familiar with specific directories housing particular types of files. For instance, the /home directory has a separate folder for every user, similar to the C:\Users directory on Windows. On Linux, /bin and /usr/bin store system files and user binaries (programs), respectively. The Windows equivalents would be C:\Windows\System32 and C:\Program Files, respectively. Similarly, /lib and /usr/lib contain shared libraries and kernel modules, same as C:\Windows\System32. The /boot directory contains the bootloader and kernel files, whereas the bootloader's config files are located in /etc along with other configuration files. Windows stores the bootloader and the kernel in a hidden EFI partition and the C:\Windows\System32 folder, respectively. Linux users mount removable drives in the /media or /run/media directories. All of these designated directories live under the "/" root directory. This is to say that Linux treats everything as a file, and has a special-purpose directory for system, user, configuration, and boot files, among other things. This is in contrast to Windows, where a lot of data belonging to your OS, along with software and documents, is typically stored on the same C: directory. The Windows system might seem convenient and intuitive, but Linux enjoys certain benefits due to the inherent separation of directories. You don't need to worry about broken file paths when swapping or expanding storage, since the drives are decoupled from physical disks. The unified file tree also allows multiple disks, servers, and cloud storage to appear as a single, homogeneous drive. Writing scripts and managing files via the terminal is also cleaner since drive letters aren't fluctuating. Windows stuck with drive letters due to compatibility, but Linux made the smarter choice After four decades of Windows, it's easy to see why Microsoft didn't replace conventional drive letters. The aim was to preserve backwards compatibility both in terms of hardware and software. However, when Linux came out in the early 1990s, the unified file tree approach introduced definitive advantages. Neither approach is universally superior, but the Linux way does make sense in a lot of ways.