file type : it can be of binary, ASCII, EBCDIC or local type (the latter to transfer the files
among hosts using bytes of different dimensions)
file format : FTP defines three types of format checking:
nonprint : it means that the file doesn't contain any vertical format indication;
Telnet : with vertical format indications;
Fortran : the first character of each line is a checking character which
specifies the formatting.
transmission modality
: it specifies how the transmission through the TCP data connection occurs. FTP
defines thee transmission modality:
blocks : the file is transferred in a series of blocks contained one or more
header bytes. The transfer occurs in the same sequence where
the data are in the file;
compressed : a simple encoding algorithm compresses the repetitions of a
same byte, the encoding is represented by a special symbol
followed by a calculation;
continuous : the file is transferred as a byte continuous flux.