EDT (Digital)
| Company type | Software |
|---|---|
| Industry | Computer software |
| Founder | Digital Equipment Corporation (DEC) |
| Products | Text editor |
| Parent | Digital Equipment Corporation |
EDT is a text editor designed around character input, created by Digital Equipment Corporation (DEC) specifically for PDP-11 machines operating under RSX-11, RSTS/E, and RT-11 systems, and was subsequently modified for the OpenVMS platform. It functions through single keystroke commands and utilizes function keys to execute various operations. Originally launched as a line-oriented editor, EDT's screen-based interface developed from the Keyboard Editor (KED) on RT-11, incorporating improvements to ensure functionality across multiple DEC operating environments.
This editor offers both line and screen editing modes. In its screen mode, users can modify text directly by typing and invoke commands using keypad keys. Basic cursor movement is facilitated by arrow keys, while the keypad provides more sophisticated navigation and search capabilities. EDT implements the "Gold Key" command structure, where the PF1 key serves as a prefix to unlock an extensive set of commands accessible via both the keypad and main keyboard. Pressing PF2 displays contextual help related to key functions.
Customization of default behaviors and key mappings is possible through initialization files that are processed during startup.
DEC later introduced the TPU, a flexible programming language designed for building text editors on the OpenVMS system. TPU was used to develop the standard editor EVE, as well as a rewritten version of EDT. EVE features an emulator replicating the EDT screen mode keypad layout to facilitate user adaptation. Both EVE and the TPU-based iteration of EDT continue to be distributed with OpenVMS.
Several EDT-inspired editors have emerged on other operating systems, including sedt, which is an EDT-based editor tailored for Unix platforms.