A ZX-Spectrum +3 with Compact Flash interface
The Sinclair ZX-Spectrum like many other 8-bit computers where not designed to be able to use a harddrive or CD-rom, compact flash was out of the question. The storage medium of choice for the ZX-Spectrum and most other 8-bit home computer during the 80′ies was the cassette, a cheap and relatively reliable storage medium but also a very slow and inflexible solution. Sinclair knew about this and developed a storage medium called Microdrives but they never caught on and they were not that good in comparison with 5.25 inch floppy diskettes.
In comparison with other 8-bit computers the ZX-Spectrum did not have a common standard for a floppy disc interface. There where third party floppy disk solutions but they where expensive. When the Sinclair ZX-Spectrum +3 was released it was designed to incorporate an obscure three inch format floppy drive. Three inch floppy disks where most common amongst Amstrad computers, Amstrad now owned Sinclair so the later Spectrums looked a lot like Amstrads own home computers of that time.
Compact Flash cards are a great alternative for storage especially for vintage computers that do not use disk swapping. Files are small and load instantly, often it is possible to just attach the compact flash card to a PC and transfer files over without serial ports and transfer programs.
There are many ZX-Spectrum enthusiasts around that still develop hardware and software for the classic computers, hard drive interfaces and floppy solutions are not as rare as they where during the heydays of the ZX-Spectrum in the early 80′ies.
The Sinclair ZX-Spectrum +3 is an interesting Spectrum model. It has an internal floppy drive and a proper keyboard instead of the sorry excuse for a keyboard on the very earliest Spectrum models. It is possible to mount an Amiga 720 KB floppy drive to the +3, and it is possible to copy snapshot images of ZX-Spectrum games to the floppy from a PC. The +3 have some compatibility problems with older software but during my testing those games where rare to run into.