Great items for chip collectors !!!
 
 Ultra RARE Russian Soviet Clone of Western Digital FDC1793 (Floppy Disk Controller)

IC from the Old Stock, in working order.

KR1818VG93 - (40-pins, Unknown plant, Unmarked Year of produce) USSR Plastic clone of WD FDC1793 (Floppy Disk Controller).
Very Rare because it not marked.
 
Often used in Beta-disk ZX-Spectrum Floppy Controller for TR-DOS

en.wikipedia.org/wiki/Beta_Disk_Interface

Also for more information You may visit -  en.wikipedia.org/wiki/Western_Digital_FD1771 

IC from the Old Stock, in working order.