About the ZX Interface 1 and ZX Microdrive

The ZX Interface 1 provided the Spectrum with local area networking, an RS-232 serial port and a connection to attach up to eight ZX Microdrives. Software to control these devices was contained in a new (shadow) ROM which provides extra BASIC commands as well as adding the ability to create your own.

The Microdrive was designed as a cheap alternative to the (very) expensive disk systems that were around for other machines at the time. It was basically a super-fast cassette system that could load data at around 15KB/s from a "cartridge" that contained a maximum of ~92KB of programs and data.

Spectaculator supports Interface 1, Microdrive and RS-232 serial port emulation at the hardware level for maximum compatibility. Support for the LAN will be added at a later date. It even generates the Microdrive motor noise when a unit is running!

Microdrive cartridges are emulated in the form of .mdr files. These files can be transferred to other emulators supporting the .mdr format.

The Introduction, Games and Business cartridges supplied with new Microdrives are available to download from Spectrum Computing.

For further information, see the ZX Interface 1 and ZX Microdrive manual, available here.

Tip

  • When creating new Microdrive cartridges, don't forget to format them before trying to read or write to them. Normally, a Microdrive not present error occurs if you try this.

Note

  • Jetset Willy has a famous bug whereby when you pause the game, it pauses forever if the Interface 1 is attached! An error in the code accidentally reads from port 0 which halts the processor until the current Microdrive supplies the next byte of data. However, if the Microdrive motor isn't running (as in JSW's case), this locks the machine. You will need to reset the Spectrum, if this happens.

  • Treat Microdrive cartridge files just like the real thing - do not reset the Spectrum or exit Spectaculator while the Spectrum is reading or writing to a cartridge.