Using a Raspberry Pi Zero SCSI adapter to bring legacy and retro systems into the future

Hard drives for early computers are decades old and prone to failure, prompting a need for modern storage adapters.

Despite the push for modernization in IT, many organizations retain dependencies on legacy platforms and the software that runs on them. With age, maintaining these platforms is becoming increasingly complex, as demagnetization of floppy and hard disks and scarcity of new old stock storage media requires scavenging internet auction websites for decades-old parts. As these parts were produced contemporaneously with the parts that failed, new solutions created by enthusiasts are being developed to bring legacy and retro systems into the future.

One such project is the RaSCSI, which uses the Raspberry Pi as an SCSI target device emulator. RaSCSI was designed by Japanese hardware hacker GIMONS, with physical devices produced by Akihabara electronics shop Kenchan. GIMONS provides the documentation for others to produce the physical hardware needed, making it possible to create your own, provided you have working knowledge of electrical design. Of note, earlier variants use the full-size Raspberry Pi, though the Kenchan variant is the first to use the smaller Raspberry Pi Zero.

The RaSCSI is capable of acting as a virtual SASI/SCSI disk, permitting the use of floppy disk, CD ISO, and virtual hard disk images loaded from an SD card. The system is interoperable with classic Macintosh, Windows systems, and Japan-exclusive home computers, including the Sharp X68000, NEC PC-98, Fujitsu FM-TOWNS, and MSX. While it is likely possible to use with other systems, like the Commodore Amiga or Acorn Archimedes, peculiarities and nonstandard implementations of SCSI may produce unexpected results.

It is possible to use the RaSCSI as a TAP device, providing an Internet connection. GIMONS only guarantees this for the X68000-through the use of the Neptune-X device driver-though it may also be possible to adapt it for use on other systems.

Source code for the RaSCSI server software (which runs on the Raspberry Pi) and X68000-specific components for file system and tap device relays are available.

The Kenchan variant is available in D-SUB half-pitch, used more commonly in computers in the United States, as well as Amphenol half-pitch and full-pitch versions more common to Japan and Europe.