In the diagram below, file transfers occur between students and uiarchive . Your desktop system acts only as a terminal, handling keyboard input and screen output, and is not involved in file transactions between the other two machines. The right part of the diagram is just like the previous illustration, where students has replaced your PC as the local host, and uiarchive has replaced students as the remote host. Typically, command-line programs require the user to type the commands needed for carrying out ftp actions. In graphical programs, ftp actions are carried out by clicking on buttons and icons, and by choosing from menus or dialog boxes.
Binary mode duplicates a file exactly, bit for bit.
If such files are not transferred in binary mode, they will not be usable. When using command-line ftp programs, you must specify in which mode the file is to be transferred. Note that some graphical programs, such as Macintosh Fetch, can interpret the file format and send the file in the correct mode automatically. If you don't know what type of file you're dealing with, often the file extension can help you figure it out. If a file has some other extension, chances are it's binary.