Editing File Transfer Protocol (section)

===Data transfer modes===
Data transfer can be done in any of three modes:<ref name="for" /><ref name="tcpip" />
* Stream mode (MODE S): Data is sent as a continuous stream, relieving FTP from doing any processing. Rather, all processing is left up to [[Transmission Control Protocol|TCP]]. No End-of-file indicator is needed, unless the data is divided into [[Record (computer science)|records]].
* Block mode (MODE B): Designed primarily for transferring record-oriented files (STRU R), although can also be used to transfer stream-oriented (STRU F) text files. FTP puts each record (or line) of data into several blocks (block header, byte count, and data field) and then passes it on to TCP.<ref name="clark" />
* Compressed mode (MODE C): Extends MODE B with data compression using [[run-length encoding]].

Most contemporary FTP clients and servers do not implement MODE B or MODE C; FTP clients and servers for mainframe and minicomputer operating systems are the exception to that.

Some FTP software also implements a [[DEFLATE]]-based compressed mode, sometimes called "Mode Z" after the command that enables it. This mode was described in an [[Internet Draft]], but not standardized.<ref>{{cite IETF |title=Deflate transmission mode for FTP |draft=draft-preston-ftpext-deflate-03 |first=J. |last=Preston |date=January 2005 |publisher=[[Internet Engineering Task Force|IETF]] |access-date=27 January 2016}}</ref>

[[GridFTP]] defines additional modes, MODE E<ref>{{Cite web|last=Allcock|first=W.|date=April 2003|title=GridFTP: Protocol Extensions to FTP for the Grid|url=https://ogf.org/documents/GFD.20.pdf}}</ref> and MODE X,<ref>{{Cite web|last=Mandrichenko|first=I.|date=May 4, 2005|title=GridFTP v2 Protocol Description|url=https://ogf.org/documents/GFD.47.pdf}}</ref> as extensions of MODE B.