ReadCommand struc ; data struct to describe a read command PackSize db 0 Reserved db 0 BlockCount dw 0 BufferAddr dd 0 BlockNumLow dd 0 BlockNumHigh dd 0 ReadCommand ends DiskAddressFD ReadCommand<10h,0,20h,10000000h,138e4h,0> ; read 20h sectors from sector 0x138e4 into address 1000:0000