Your computer has probably never touched a floppy disk. There’s a good chance you haven’t either. And yet, sitting right there in File Explorer is a drive letter that only exists because of them. Not A:, not B:, but C:, as if the alphabet decided the first two letters weren’t pulling their weight. If you plug in a USB drive, it shows up somewhere around D: or E:. Add a second internal drive, and the letters keep climbing.
Most people notice it once, pause for a second, maybe squint a little, and then move on. Which is completely fair. But the real reason behind it, and what those first two letters are doing in 2026, is quite a good story.
The floppy disk era made a sensible, temporary choice
Then it accidentally became permanent
Before hard drives were affordable or even common, personal computers ran almost entirely off floppy disks. These were flat, flexible magnetic discs sealed inside a thin plastic shell, and as any seasoned Windows user remembers, they were the primary way to handle everything from the operating system to your personal files.
One of the early operating systems, CP/M (Control Program for Microcomputers) from the 1970s, introduced the idea of using drive letters to identify storage. The first floppy drive was A:, and the second was B:. Now, when Microsoft built MS-DOS, short for Microsoft Disk Operating System, heavily inspired by CP/M, it carried that same idea forward. And when the original IBM PC showed up in 1981, it often came with two 5.25-inch floppy drives already mapped to A: and B:.
In a two-drive setup, users would typically boot the OS from the A: drive, then use the B: drive for data storage or a second program disk — which, if you squint at it, isn’t entirely unlike how people today split their NVMe drive from a secondary SSD for personal files. It’s the same idea, just a lot noisier and more fragile. What’s even stranger is what happened when a machine only had one floppy drive. The operating system still preserved the idea of A: and B:, treating the single drive as both, which resulted in those now-legendary prompts: “Please insert source disk into drive A:… Now insert destination disk into drive A:” This was a physical shuffle that allowed a single drive to emulate two.
Crucially, the system BIOS and the floppy disk controller had fixed hardware addresses for drive A and drive B. Because these were hard-coded at the BIOS level, DOS assigned those letters by default to any floppy hardware it detected. So, when hard drives started appearing in the early 1980s, there was no reshuffling to reclaim the first letters of the alphabet. Since A: and B: were already reserved for the floppy controller’s legacy addresses, the first hard disk naturally became C:. It made complete sense at the time—nobody expected it to be the standard forty-plus years later still.
Computer Storage: A Brief History of Storing Your Personal Data
Computer storage has come a long way, and has a fascinating history.
The reason C: never moved isn’t nostalgia
It’s the weight of everything built on top of it
You might wonder why Microsoft never just cleaned this up. Windows has had plenty of major overhauls; surely someone could’ve slipped in a clean reset of the drive letters along the way.
The answer is that C: stopped being just a label a long time ago. For decades, software has been written with the expectation that Windows lives on the C: drive. Not as a suggestion, but as a given. Changing that now would not just be renaming a drive, but breaking installers, hardcoded file paths, registry entries, and system shortcuts. A long tail of legacy software would start behaving unpredictably, and none of it would fail in the same way.
While modern computers haven’t seen a floppy disk in years, the convention remains: Windows automatically assigns the label C: to the main installation partition because so much software is built with that “C:” path as its home base. It’s a classic case of technical debt where the “correct” move would cause so much collateral damage that it’s simply not worth the headache.
Interestingly, A: and B: never really went away. They are still there, just waiting in the wings. Windows Disk Management lets you safely manage hard drive partitions while still listing them as available, so you can technically assign them to an external storage device if you’re feeling rebellious. However, there’s a catch: because those letters were originally intended for removable floppy disks, Windows Search doesn’t index them by default. If you move your project folder to an “A:” drive, don’t be surprised when your files no longer appear in your Start Menu search results.
The floppy disk is gone from your desk, but it’s still alive
It’s holding the world together in stranger places than you’d think
The floppy disk, the very thing responsible for the C: drive’s existence, has never fully left us. It lives on first as a hieroglyph: on virtually every application today, “Save” is represented by a 3.5-inch floppy disk. Funny thing is, a lot of people who click it have never actually touched one. It is one of many ancient features Windows 11 still supports.
Beyond the desktop, in some corners of the real world, floppies are still doing actual work. Certain Boeing 747-400 aircraft, for instance, rely on 3.5-inch floppy disks to load critical software updates into their flight systems. Yes, really. Engineers have to show up and manually slot them in, often as part of a monthly routine. Similarly, the U.S. Air Force relied on 8-inch floppy disks to manage its nuclear arsenal control system for decades, only finishing its transition to modern solid-state storage in June 2019.
Japan also recently reached a major milestone in its “war on floppies.” Up until June 2024, businesses were still required to submit data on physical media such as floppy disks and CDs under over 1,000 different regulations. It took a deliberate push from the country’s Digital Agency to finally retire those requirements and drag things into the present.
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How can such old technology still be in use?
Every odd thing your PC does has a reason
If you ever find yourself explaining this to someone and watching their face shift from confusion to mild disbelief — that’s the right reaction. It means the history landed. Most of what’s weird about your computer has a story behind it. C: just happens to be one of the better ones.
