The Cumana Disk Interface is a chunky 11cm x 14.5cm x 1.5cm creme coloured interface which plugs into one of the expansion slots on the Acorn Electron 1/AP1 or Rombox+ interface.

The Cumana Disk Interface was in fact the very first disk interface, brought out before the release of the ACORN PLUS 3 by Acorn Computers. It uses its own filing system, CDFS, which, in many ways, is far superior to that of the standardised ADFS 1D00 and DFS E00 that are more dominant.

The Cumana Disk Interface uses none of the Acorn Electron's memory and powers itself from an on-board battery which also displays a 24 hour clock and correct date and time on the opening screen. This means all games can be transferred from tape to disk and run without problem.

The Cumana Disk Interface also boasts a spare 16K ROM socket which can be used for a ROM chip. Slogger's T2CU is often found occupying this socket.

The Cumana Disk Interface can be used with any Acorn disc drive that has its own power supply.

The Cumana Disk Interface came supplied with a User Guide and a utilities disk (originally on 5.25" disk) containing programs to convert between ADFS/DFS and CDFS (and vice versa). You also require the utilities disk to format discs to the CDFS format. The interface alone is of very little use.

The CDFS format was a peculiarity in the Acorn Electron world and fell out of favour as soon as the AP3 and AP4 were released in 1986. CDFS disks are regretfully neither supported by emulation or any archive websites. However, if you write a DFS disc using FDC, you could use Cumana's utility disk to copy the files to the CDFS system.

The Cumana Disk Interface was originally available by mail order from Cumana for £99.95. A second hand Cumana Disk Interface with utility disk will usually sell on eBay for £50-£100.