INT 6F - 10NET - LOCK HANDLE AH = 07h BX = file handle CX:DX = starting offset in file SI = record length Return: CF clear if successful CF set on error AX = error code (see also AH=00h) 0002h file not found SeeAlso: AH=08h"10NET",AH=0Fh,INT 21/AH=5Ch