This was part of a "Microdrive" series, but it doesn't have anything to do with MD management as such. In fact, it does what it says on the tin: it reports the Spectrum's free memory.#It does require {hardware|1000192} to be present, because it uses that to extend the BASIC grammar.
Files2
Free Memory
1984 · Your Computer
Runnable
Tapes, snapshots and disks — these boot in the emulator.