The Memotech MTX Series
MEMOTECH DISK SYSTEMS
HDX Disc System
In addition to the FDX
and SDX floppy disk drive options
for the MTX, Memotech also announced a hard disk
version of the FDX which could accommodate a
small (10, 20 or 32 MB) hard disk installed in an FDX
case alongside a single 1MB floppy disk.
According to the
Manual, the HDX used an 8MHz Z80H processor. I have never seen
one of these, and given the expected price (the retail
price was never announced), I
would guess that very few, if any, were actually sold.
The image above shows how the HDX might have looked with a
half-height hard disk adjacent to the floppy drive, it is almost
certain that no actual pictures of HDX systems have survived.