Notes
RemarksD40/D80 was floppy system produced by Slovak company Didaktik Skalica.
This product was spread mainly in the Czech Republic (and Slovakia too).
D40/80 consists of power supply, drive (D40 = 5.25 DD; D80 = 3.5 DD) and port for the second drive B (max 2 drives can be connected). It has 16Kb EPROM with an operating system called M-DOS (the official versions are 1.0, 1.0 +, 2.0), 2Kb SRAM for system variables, the controller WD2797 (for newer models controller Intel 8272) and separated data and address bus.
There is a parallel interface with a chip 8255 (eg, for printer). Standard floppy with D40/D80 is 40/80x09 (feet x sectors) and 512 bytes per sector.
When you connect HD drive, capacity does not increase (still, it will work as DD). Max number of files on the disk is 128. System preserves the original computer ROM.