Contributor: ALEX RUSSKIH Unit Tools; Interface Function DriveValid(Drive: Char): Boolean; Function SelectDrive(Drive: Char): Word; Implementation Function DriveValid; Assembler; Asm Mov Ah,19h Int 21h Mov Bl,Al Mov Dl,Drive Sub Dl,'A' Mov Ah,0Eh Int 21h Mov Ah,19h Int 21h Mov Cx,0 Cmp Al,Dl Jne @@1 Mov Cx,1 Mov Dl,Bl Mov Ah,0Eh Int 21h @@1: Xchg Ax,Cx End; Function SelectDrive; Assembler; Asm Mov Dl,Drive Sub Dl,'A' Mov Ah,0Eh Int 21h End; End.