File transfer
Encyclopedia
File transfer is a generic term for the act of transmitting
files over a computer network
or the Internet
. There are numerous ways and protocols to transfer files over a network. Computers which provide a file transfer service are often called file server
s. Depending on the client
's perspective the data transfer is called uploading or downloading
. File transfer for the enterprise now increasingly is done with Managed File Transfer.
There are 2 types of file transfers:
File transfer can take place over a variety of levels:
s stored as a single unit in a file system
, plus any relevant metadata
such as the filename
, file size and timestamp
. File transfer protocols usually operate on top of a lower-level protocol in a protocol stack
. For example, the HTTP protocol operates at the topmost application layer of the TCP/IP stack, whereas XMODEM, YMODEM, and ZMODEM typically operate across RS-232
serial connections.
Transmission (telecommunications)
Transmission, in telecommunications, is the process of sending, propagating and receiving an analogue or digital information signal over a physical point-to-point or point-to-multipoint transmission medium, either wired, optical fiber or wireless...
files over a computer network
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
or the Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
. There are numerous ways and protocols to transfer files over a network. Computers which provide a file transfer service are often called file server
File server
In computing, a file server is a computer attached to a network that has the primary purpose of providing a location for shared disk access, i.e. shared storage of computer files that can be accessed by the workstations that are attached to the computer network...
s. Depending on the client
Client (computing)
A client is an application or system that accesses a service made available by a server. The server is often on another computer system, in which case the client accesses the service by way of a network....
's perspective the data transfer is called uploading or downloading
Uploading and downloading
In computer networks, to download means to receive data to a local system from a remote system, or to initiate such a data transfer. Examples of a remote system from which a download might be performed include a webserver, FTP server, email server, or other similar systems...
. File transfer for the enterprise now increasingly is done with Managed File Transfer.
There are 2 types of file transfers:
- Pull-basedPull technologyPull technology or client pull is a style of network communication where the initial request for data originates from the client, and then is responded to by the server. The reverse is known as push technology, where the server pushes data to clients.. Usually, customers will look for a site and...
file transfers where the receiver initiates a file transmission request - Push-basedPush technologyPush technology, or server push, describes a style of Internet-based communication where the request for a given transaction is initiated by the publisher or central server...
file transfers where the sender initiates a file transmission request.
File transfer can take place over a variety of levels:
- TransparentNetwork transparencyNetwork transparency in its most general sense refers to the ability of a protocol to transmit data over the network in a manner which is transparent to those using the applications that are using the protocol....
file transfers over network file systemsDistributed file systemNetwork file system may refer to:* A distributed file system, which is accessed over a computer network* Network File System , a specific brand of distributed file system... - Explicit file transfers from dedicated file transfer services like FTPFile Transfer ProtocolFile Transfer Protocol is a standard network protocol used to transfer files from one host to another host over a TCP-based network, such as the Internet. FTP is built on a client-server architecture and utilizes separate control and data connections between the client and server...
or HTTPHypertext Transfer ProtocolThe Hypertext Transfer Protocol is a networking protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web.... - Distributed file transfers over peer-to-peerPeer-to-peerPeer-to-peer computing or networking is a distributed application architecture that partitions tasks or workloads among peers. Peers are equally privileged, equipotent participants in the application...
networks like Bittorent or GnutellaGnutellaGnutella is a large peer-to-peer network which, at the time of its creation, was the first decentralized peer-to-peer network of its kind, leading to other, later networks adopting the model... - In IBM Systems Network Architecture, LU 6.2 peer-to-peer file transfer programs such as CA, Inc.'s XCOM Data TransportXCOM Data TransportXCOM, is a proprietary file transfer utility owned by Computer Associates. It has been popular on mainframe and midrange computers for many decades and functions on both SNA and TCP/IP networks. XCOM establishes a peer-to-peer connection as opposed to FTP which is client/server relationship...
- File transfers over instant messagingInstant messagingInstant Messaging is a form of real-time direct text-based chatting communication in push mode between two or more people using personal computers or other devices, along with shared clients. The user's text is conveyed over a network, such as the Internet...
or LAN messengerLAN messengerA LAN messenger is an instant messaging program designed for use within a single local area network .There are advantages using a LAN messenger over a normal instant messenger. The LAN messenger runs inside a company or private LAN, and so an active Internet connection or a central server is not... - File transfers between computerComputerA computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
s and peripheral devices - File transfers over direct modemModemA modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...
or serialSerial portIn computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time...
(null modemNull modemNull modem is a communication method to connect two DTEs directly using an RS-232 serial cable. The name stems from the historical use of the RS-232 cable to connect two teleprinter devices to modems in order to communicate with one another; null modem communication was possible by instead using...
) links, such as XMODEMXMODEMXMODEM is a simple file transfer protocol developed as a quick hack by Ward Christensen for use in his 1977 MODEM.ASM terminal program. XMODEM became extremely popular in the early bulletin board system market, largely because it was so simple to implement...
, YMODEMYMODEMYMODEM is a protocol for file transfer used between modems. YMODEM was developed by Chuck Forsberg as the successor to XMODEM and MODEM7, and was first implemented in his CP/M YAM program...
and ZMODEMZMODEMZMODEM is a file transfer protocol developed by Chuck Forsberg in 1986, in a project funded by Telenet in order to improve file transfers on their X.25 network...
.
Protocols
A file transfer protocol is a convention that describes how to transfer files between two computing endpoints. They are meant solely to send the stream of bitBit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...
s stored as a single unit in a file system
File system
A file system is a means to organize data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device which contain it. A file system organizes data in an efficient manner and is tuned to the...
, plus any relevant metadata
Metadata
The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...
such as the filename
Filename
The filename is metadata about a file; a string used to uniquely identify a file stored on the file system. Different file systems impose different restrictions on length and allowed characters on filenames.A filename includes one or more of these components:...
, file size and timestamp
Timestamp
A timestamp is a sequence of characters, denoting the date or time at which a certain event occurred. A timestamp is the time at which an event is recorded by a computer, not the time of the event itself...
. File transfer protocols usually operate on top of a lower-level protocol in a protocol stack
Protocol stack
The protocol stack is an implementation of a computer networking protocol suite. The terms are often used interchangeably. Strictly speaking, the suite is the definition of the protocols, and the stack is the software implementation of them....
. For example, the HTTP protocol operates at the topmost application layer of the TCP/IP stack, whereas XMODEM, YMODEM, and ZMODEM typically operate across RS-232
RS-232
In telecommunications, RS-232 is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE and a DCE . It is commonly used in computer serial ports...
serial connections.
See also
- List of file transfer protocols
- File sharingFile sharingFile sharing is the practice of distributing or providing access to digitally stored information, such as computer programs, multimedia , documents, or electronic books. It may be implemented through a variety of ways...
- USB flash drive - Security threats