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Below are some familiar terms that may have slightly different denotations than what most are used to in the present day. All terms come directly from the RFCs referenced for this site which range from April 1969 to late 1973 and beyond.


ARPANET- Advanced Research Projects Agency Network
ASCII - American Standard Code for Information Interchange. The US ASCII character set as defined in NIC #7104.

BBN - Bolt, Beranek and Newman. The company contracted to build the Interface Message Processors.
Block Data Terminals - Devices such as printers, card readers, paper tape, and magnetic tape equipment


Data Connection - A simplex connection over which data is transferred, in a specified byte size, mode and type. The data transferred may be a part of a file, an entire file or a number of files.
Data Socket - The socket on which an application layer process "listens" for a data connection.
Direct Use - Implies that a network user is "logged" into a remote host, uses it as a local user, and interacts with the remote system via a terminal (teletypewriter, graphics console) or a computer. Differences in terminal characteristics are handled by host system programs, in accordance with standard protocols (such as TELNET (RFC 97) for teletypewriter communications, NETRJS (RFC 88) for remote job entry. These are old examples). The user, however, has to know the different conventions of the remote systems, in order to use them.
DNS - Domain Name System developed to allow a structured network, in the form of domain names, to proliferate (.com, .gov, .mil, .org, .net, .int)

Efficiency - CPU time or cost
EOF - The end-of-file condition that for example, defines the end of a file being transferred.
Error Recovery - A procedure that allows a user to recover form certain transmission errors such as failure of either Host system or transfer process.

File - A sequence of bits, a sequence or characters, or programs of arbitrary length uniquely identified by a pathname.
FTP Commands - A set of commands that comprise the control information flowing from the user-FTP to the server-FTP process.
Full duplex - Full-duplex data transmission means that data can be transmitted in both directions on a signal carrier at the same time. For example, on a local area network with a technology that has full-duplex transmission, one workstation can be sending data on the line while another workstation is receiving data. Full-duplex transmission necessarily implies a bidirectional line (one that can move data in both directions).


Host Socket - This is commonly known as port in todays terminology.
Host-to-Host - The Host-Host Protocol is discussed in the ARPANET section of the THINK website.

ICCC - International Conference on Computer Communication
IMP - Interface Message Processor
IEEE - Institute of Electrical and Electronics Engineers
Indefinite Bit Stream - A method of transfer that terminates only when the connection is closed and represents a single transaction for the duration of the connection
Initial Connection Protocol (ICP) - The protocol used by the TELNET protocol to make an initial connection to a specified server



Local Byte Size - The number of bits used for the local system's file storage representation, e.g. NVT-ASCII has different data storage representations in different systems: PDP-10's generally store NVT-ASCII as five 7-bit ASCII characters, left justified in a 36 bit word; 360's store NVT-ASCII as 8-bit EBCDIC codes; and Multics stores NVT-ASCII as four 9-bit characters in a 36-bit word. The local bytes would be 7, 8, and 9, respectively.
Logical Blocking - A term focused around the grouping/blocking of data messages over a transaction. The term is synonymous with transfer modes.

Messages - Physical blocks of data communicated between NCP's
Mode of Transfer - The mode in which data is to be transferred via the data connection. The mode defines the data format including End Of File.

NCC - Network Control Center - Set up to monitor the status of the IMPs
NCP - Network Control Protocol - The first host to host protocol
NLS - Online System
NWG - Network Working Group
NVT - The Network Virtual Terminal as defined in the ARPANET TELNET Protocol. NVT was a bi-directional character device, representing characters as 7-bit ASCII codes, using an 8-bit field.


Pathname - Defined to be the character string which must be input to a file system by a user in order to identify a file. Pathname normally contains device and/or directory names, and file name specification. Each user must follow the file naming conventions of the file systems he wishes to use.
Print File - Presumably it is a file which is intended to be sent (eventually) to a printer process to create a hard copy. Many operating systems (particularly those which are batch-processing oriented) allow the programmer to include control codes within a file to be printed, to control the vertical format of the printed page--for example, single/double line spacing, overprinting, and page ejection. A "print file" is one which includes such vertical format control ("VFC") information. [RFC 448]


Receiver - The Host (user, server, or other) that is to receiver the requested file.
Record - A sequential file may be structured as a number of contiguous parts called records. Record structures are supported by FTP but are not mandatory.
Reliability - error rate and failure rate
Reply - An acknowledgment (positive or negative) sent from the server to the user via the telnet connections. The general form of a reply is a completion code (including error codes) followed by an ASCII text string. The codes are for use by programs and the text is for human users.
RFC - Request For Comments

Sender - The Host (user, server, or other) sending the requested file.
Server-FTP process - A process or set of processes which perform the function of file transfer in cooperation with a user-FTP process. The server-FTP process must interpret and respond to user commands and initiate the data connection.
Server site - A HOST site which has a server-FTP process.
Server Socket - This is commonly known as port in todays terminology.
Server-TELNET process - A TELNET process which listens on a specified socket for an ICP initiated by a user-TELNET, and performs in accordance with the ARPANET TELNET Protocol.
Simplex - This type of communication means that communication can only flow in one direction and never flow back the other way.
Speed - real time delay and transmission rate
Sub-system - A system operating above the network level and is thus used to distinguish between the network level and the Telnet process built on top of the network level in early implementations.
System calls - Essentially an API mechanism allowing Telnet to begin interfacing with the operating system

TCP - Transmission Control Protocol. This protocol would replace the Network Control Protocol, and allows for Internetworking. TCP splits into TCP and IP, where TCP is the end to end process, and IP is the network routing process.
Telnet Connection - The full-duplex communication path between a user-TELNET and a server-TELNET. The TELNET connections are established via the standard ARPANET Initial Connection Protocol (ICP).
Terminal - A terminal (sometimes qualified as a "dumb" terminal) is an end-use device (usually with display monitor and keyboard) with little or no software of its own that relies on a mainframe or another computer for its "intelligence." In this case, the term is used to mean any personal computer or user workstation that is hooked up to the network
TIP - Terminal IMP - A device allowing direct terminal access to the network.
Time-sharing computer - A system which allows mulitple-users to run processes on a computer
Transaction Sequence - an entity of information communicated between cooperating processes
Transfer Byte Size - The byte size specified for the transfer of data. The data connection is opened with this byte size. Data connection byte size is not necessarily the byte size in which data is to be stored in a system, and may not be related to the structure of data.
Transparent Mode - A mode of transfer where transactions end whenever a special escape sequence is encountered. It requires some type of parsing of the data stream.
Type - The data representation type used for data transfer and storage. Type implies certain transformations between the time of data storage and data transfer.

Usage - suitablility for various application and user classes
User - A process on behalf of a human being or a human being wishing to obtain file transfer service.
User-FTP process - A process or set of processes which perform the function of file transfer in cooperation with a server-FTP process.
User-TELNET process - A TELNET process which initiates ICP to make a connection to a specified server-TELNET socket, and performs in accordance with the ARPANET TELNET protocol.







Written by the THINK Protocols team, CS Dept, UT Austin
Please direct comments to Chris Edmondson-Yurkanan.

Tuesday, 11-Jun-2002 10:19:44 CDT.