When the ZX Spectrum came out in 1982 the options for data storage on home computers were very limited. You usually had the choice of audio cassette tape or floppy disk. The ZX Spectrum initially came with audio cassette storage via an external cassette player/recorder. Sinclair Research would develop a variation of tape storage in their microdrive system via their Interface 1 add-on and it was only very much later that floppy disk storage would appear as a add-on option (i.e. DISCiPLE drive) or as a official computer model (the ZX Spectrum +3)
Now, lets fast forward to the present. Audio tape cassettes and floppy disks are very much a thing of the past and getting new blank tapes or disks is difficult to almost impossible.
However all is not lost as the retro community has been very busy in the intervening years and has come up with many alternatives to tape and disk storage. These alternatives are usually based on either Compact Flash or SD-Card. Below is a short list of some DIY projects:
“Everdrive”/DivMMC for Spectrum list
View at Medium.com
SD-Card interface round-up
ZXMMC+ (sd-card access, IF-1 – RS-232 and Network), 1MB ram/rom, Kempston joystick
ZXcard DIY SD/MMC interface
maxduino – Unified firmware for tzxduino and casduino
Tapuino-Reloaded – A reworked smd version of the Tapuino Mini Pro.
TzxDuino-Reloaded – A reloaded version of the TzxDuino
TZXDuino Arduino based TZX