The Acorn Electron was the budget version of the BBC Model B made by Acorn Computers, and produced in ~ 1983.
In it’s crudest form, it came with 32kb of RAM and a stripped down “v2” variant of BBC Basic. Video output was via a TV Modulator, an RGB Colour monitor or a “Green Screen” display, and media support was provided via a Cassette tape to load and save content. The “Acorn Electron Plus 3” module was needed to use Floppy Disks, it included the Floppy interface itself, and an ADFS (Advanced Disk Filing System) ROM, and the drive itself.
The optional expansion module – the “Acorn Electron Plus 1” provided two ROM slots, an analogue interface and a parallel port. The analogue interface was normally used for joysticks, the parallel for a printer.