Browse Prior Art Database

Decode Encode Language (DEL) (RFC0005) Disclosure Number: IPCOM000003635D
Original Publication Date: 1969-Jun-01
Included in the Prior Art Database: 2019-Feb-11
Document File: 15 page(s) / 19K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Rulifson: AUTHOR

Related Documents

10.17487/RFC0005: DOI

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 13% of the total text.

Network Working Group 4691 RFC-5 Jeff Rulifson June 2, l969


:DEL, 02/06/69 1010:58 JFR ; .DSN=1; .LSP=0; [’=] AND NOT SP ; [’?]; dual transmission?


The Decode-Encode Language (DEL) is a machine independent language tailored to two specific computer network tasks:

accepting input codes from interactive consoles, giving immediate feedback, and packing the resulting information into message packets for network transmissin.

and accepting message packets from another computer, unpacking them, building trees of display information, and sending other information to the user at his interactive station.

This is a working document for the evolution of the DEL language. Comments should be made through Jeff Rulifson at SRI.


The initial ARPA network working group met at SRI on October 25-26, 1968.

It was generally agreed beforehand that the runmning of interactive programs across the network was the first problem that would be faced.

This group, already in agreement about the underlaying notions of a DEL-like approach, set down some terminology, expectations for DEL programs, and lists of proposed semantic capability.

At the meeting were Andrews, Baray, Carr, Crocker, Rulifson, and Stoughton.

A second round of meetings was then held in a piecemeal way.

Crocker meet with Rulifson at SRI on November 18, 1968. This resulted in the incorporation of formal co-routines.

and Stoughton meet with Rulifson at SRI on Decembeer 12, 1968. It was decided to meet again, as a group, probably at UTAH, in late January 1969.

The first public release of this paper was at the BBN NET meeting in Cambridge on February 13, 1969.


NST The NST library is the set of programs necessary to mesh efficiently with the code compiled at the user sites from the DEL programs it receives. The NST-DEL approach to NET interactive system communication is intended to operate over a broad spectrum.

The lowest level of NST-DEL usage is direct transmission to the server-host, information in the same format that user programs would receive at the user-host.

In this mode, the NST defaults to inaction. The DEL program does not receive universal hardware representation input but input in the normal fashion for the user-host.

And the DEL 1 program becomes merely a message builder and sender.

A more intermediate use of NST-DEL is to have echo tables for a TTY at the user-host.

In this mode, the DEL program would run a full duplex TTY for the user.

It would echo characters, translate them to the character set of the server-host, pack the translated characters in messages, and on appropriate break characters send the messages.

When messages come from the server-host, the DEL program would translate them to the user-host character set and print them on his TTY.

A more ambitious task for DEL is the operation of large, display-oriented systems from remote consoles over the NET.

Large interactive systems usually offer a lot of feedback to the user. The unusual natur...