When protecting your data meant punching a hole in it • The Register

Once upon a time, saving your bits meant punching holes in floppies

The vast majority of removable media today consists of flash drives, some with a write-protect switch or a software setting to prevent accidental writes. In the days of yore, however, notches and tabs ruled, though their implementation was not always consistent.

Microsoft's Raymond Chen took a delightful trip down memory lane this week, tracing how write protection for removable media has changed over the decades. The veteran engineer began with the eight-inch floppy disk, widely attributed to IBM in 1971, which stored around 80 kilobytes.

"The write protect notch was at the top of the leading edge," Chen wrote. "The presence of a notch made the floppy write-protected, so you started with a write-enabled floppy, and if you wanted to protect it, you punched a notch at just the right spot."

This might seem counterintuitive to modern users - why would you start with an unprotected disk and then physically damage it to protect it? But in the early days of computing, this was standard practice. The eight-inch floppy's write-protect notch was essentially a permanent modification that prevented the drive's read/write head from accessing that portion of the disk.

The 5.25-inch revolution and its quirks

The 5.25-inch disk superseded the eight-inch floppy, bringing with it a confusing change in write-protection logic. Here, the write-protect notch was on the right edge, near the top.

"The presence of a notch made the floppy write-enabled," recalled Chen. "To protect it, you covered the notch with a sticker. So it was really a write-enable notch, not a write-protect notch."

This reversal in logic - where a notch now meant "go ahead and write" rather than "don't write" - must have caused countless user errors in the transition period. The sticker solution was elegant in its simplicity: manufacturers could ship disks with the notch exposed, and users could apply a write-protect sticker when they wanted to safeguard their data.

Chen doesn't mention one popular modification for 5.25-inch disks in the days before double-sided drives became ubiquitous. As well as the notches, it was possible to take a disk and use a hole punch to create a "flippy disk," in which a user flipped the disk to use the other side (e.g. on a Texas Instruments 99/4A). It required a hole punch, a sacrificial disk, and, in this writer's experience, a fair amount of teenage optimism.

The 3.5-inch standard and cassette tapes

The advent of the 3.5-inch floppy simplified things considerably, introducing a sliding switch on the underside of the disk. An open hole meant the disk could be written, while closing the hole protected the disk. This sliding switch design proved so intuitive that it influenced later storage technologies, including some SD cards and even certain USB drives.

Then there was the compact cassette – familiar to many a computer user of the 1980s. Break the tab at the top of the cassette to protect the tape. Pop some Sellotape over it, and writing was possible. This write-protect tab on cassette tapes worked on the same principle as the 5.25-inch floppy stickers - cover the hole to enable writing, leave it open to prevent it.

It is more than a decade since Sony, one of the last major manufacturers, finally pulled the plug on floppy disk production, although supplies of the media can still be found. Chen's career at Microsoft dates back to when the company's software shipped on floppy disks. The installation media for Windows 3.1 came on half a dozen disks, while Windows 95 required 13, according to the veteran engineer.

It's worth pausing to wonder how many Windows installation disks were repurposed by users thanks to a flick of the write-protect tab or the addition of a write-enable notch. The physical nature of these write-protection mechanisms meant that data security was literally in users' hands - a concept almost unimaginable in today's software-controlled world.

The evolution of data protection

The journey from punched notches to sliding switches to software toggles reflects broader changes in how we interact with technology. Early computing required users to understand and manipulate physical mechanisms. Today's write protection is typically handled through file system permissions, encryption, or cloud-based controls that most users never see.

Yet there's something satisfying about the tactile nature of those early write-protection methods. You could see and feel whether a disk was protected. There was no ambiguity about its status. In an age of increasingly abstract digital interactions, that physical feedback provided a level of certainty that many users miss today.

For those who remember the era of floppy disks and cassette tapes, Chen's walk down memory lane is more than just nostalgia - it's a reminder of how far we've come in making technology more accessible, even if we've lost some of the hands-on understanding that came with those early, manual methods of data protection.