What do ASCII/text/binary/image/raw data mean?
Broadly speaking there are two types of FTP transfer – text transfer and binary transfer. One of the primary differences between an ASCII (American Standard Code for Information Interchange) or text and a binary transfer (in fact the only real one of note) is in the treatment of end-of-line. A binary transfer just copies the bytes with no conversion, an ASCII transfer copies bytes but also changes the end-of-line representation to that of the destination system (eg it might convert CR/LF(Carriage Return/Line Feed) to LF. Other bytes can exist and are copied as is (even non-printing bytes). One other difference, which is a result of this end-of-line conversion, is that the destination system needs to buffer an incoming line in ascii mode in order to write out the whole line (you can’t always write part lines in some systems). As a result, there may be a restriction on the maximum line length of an ASCII or text transfer, whereas there is never any such limit with a binary transfer.
