M-Systems made flash look like a USB drive

Portable files were still tied to mechanical floppies, external drives or awkward flash cards. In late 2000, M-Systems introduced DiskOnKey: a thumb-sized flash device that plugged directly into a PC's USB port and appeared as portable storage.

The clever part was not only smallness. M-Systems' 2003 filing says DiskOnKey was based on TrueFFS and patented DiskOnKey technology; TrueFFS virtualized flash sectors, spread writes by wear leveling, mapped out bad blocks and protected data when power failed mid-write.

Wired's Comdex preview captured why the product felt different: 8 MB, 16 MB and 32 MB versions plugged into USB, needed no additional software, and worked across Windows, Mac and Linux. Users did not have to learn flash memory; they got a pocket disk.

Make flash pretend to be a disk

USB gave the product a port every new PC was beginning to share.

The controller absorbed flash's erase-block and wear problems before they reached the user.

Presenting as a normal drive made adoption immediate for nontechnical users.

The pen/key shape turned storage into something people would carry daily.

A breakthrough interface often wins by hiding the new technology's weirdness and presenting the old mental model users already trust.

M-Systems said DiskOnKey reached 8 MB to 512 MB capacities by 2003 and accounted for 41% of 2002 revenue. USB flash drives then became a standard replacement for floppies, even as rivals and patent disputes crowded the category.