A homebrew magnetic core memory USB drive has successfully transferred a text file from one PC to another, in what its creator describes as possibly a world first. Japanese researcher @dydtNao demonstrated the retro-modern device working as a sneakernet tool, physically carrying data between machines rather than relying on a network.
The project first drew attention in February 2026, when @dydtNao began reviving this archaic computer memory technology. The updated build shows the concept taken further, moving both text and image files across two separate computers using storage hardware that predates modern flash memory by decades.
How the Magnetic Core Memory Drive Works
The device is unusual in almost every respect. It is roughly a foot (30 cm) square, dwarfing any conventional thumb drive. Its capacity is extraordinarily small at just 128 bytes — not gigabytes, megabytes, or even kilobytes. The stored data is also erased during the read process, a known characteristic of the underlying technology.
A demonstration video shows the USB Type-A gadget in action. As data is read to and from the drive, LEDs in an attached 32 x 32 array glow bright red, with each LED corresponding to an individual magnetic core. Windows reports the drive as having a 6.5 KB capacity, likely a quirk tied to the Raspberry Pi Pico serving as the onboard controller. The clip ends with the transferred text appearing successfully in Notepad on the destination PC.
Text and Image Transfers on 128 Bytes
Not content with a text-only demo, @dydtNao followed up with a BMP image transfer. The drive can store monochrome bitmaps up to 32 x 28 pixels. Some of the limited memory space, organized as 32 x 4, is likely consumed by the image file header, further tightening an already severe storage ceiling.
The creator plans to exhibit and demonstrate the device at Maker Faire Tokyo 2026, scheduled for September 5 and 6 at the Ariake GYM-EX venue.
The History Behind the Technology
Magnetic core memory was patented by inventor and MIT electrical engineer Jay Forrester, and the design recently marked the 75th anniversary of its patent filing. The technology served as the dominant form of random-access storage in digital computers for roughly two decades before newer memory types replaced it. Today it functions mainly as a historical curiosity, making its reappearance in a working USB storage device a notable engineering exercise.
The 32 x 32 LED array visually maps every core in real time, letting observers watch individual bits flip as files move on and off the drive. With a ceiling of 128 bytes, practical use is limited to tiny payloads, roughly the character count of a short message rather than any modern media file.
Source
Image: tomshardware.com
