EDT text editor
Encyclopedia
There are at least two major text editors named EDT. One was made by Digital Equipment Corporation, the other by what was then Sperry Univac, which later became Unisys.
that was developed by Digital Equipment Corporation
(DEC) for use on its PDP-11
series of computers (including RSX-11
, RSTS/E
and RT-11
), and later for its VAX
/VMS series as well.
The editor contained both line mode commands and a screen based editor. In screen mode, the default action for the user was to directly update text as he or she typed, with special commands available by pressing keypad commands. Arrow keys allowed for simple navigation, while keypad commands allowed for more complex navigation and searches. As with many user interfaces developed around this time, EDT used the "Gold Key" style of input first developed for the WPS-8
word processing system. "Gold Key" editing used the PF1 keypad key as a meta key
allowing the introduction of a wide variety of commands using both the keypad keys and keys on the main keyboard. Pressing the PF2 keypad key would give on-screen help on the keypad and other key combinations:
/-----------------------------------\ /-----------------------------------\
| ^ | DOWN | | | | | | FNDNXT | DEL L |
| | | | | <---- | ----> | | GOLD | HELP | | |
| | | | | LEFT | RIGHT | | | | FIND | UND L |
| UP | v | | | |--------+--------+--------+--------|
\-----------------------------------/ | PAGE | SECT | APPEND | DEL W |
DELETE Delete character | | | | |
LINEFEED Delete to beginning of word | COMMAND| FILL | REPLACE| UND W |
BACKSPACE Backup to beginning of line |--------+--------+--------+--------|
CTRL/A Compute tab level | ADVANCE| BACKUP | CUT | DEL C |
CTRL/D Decrease tab level | | | | |
CTRL/E Increase tab level | BOTTOM | TOP | PASTE | UND C |
CTRL/K Define key |--------+--------+--------+--------|
CTRL/R Refresh screen | WORD | EOL | CHAR | |
CTRL/T Adjust tabs | | | | ENTER |
CTRL/U Delete to beginning of line |CHNGCASE| DEL EOL| SPECINS| |
CTRL/W Refresh screen |-----------------+--------| |
CTRL/Z Exit to line mode | LINE | SELECT | |
| | | SUBS |
Press a key for help on that key. | OPEN LINE | RESET | |
To exit, press the spacebar. \-----------------------------------/
Users could configure default actions or define key sequences for their editor by placing EDT commands in an initialization file which would be executed upon starting the editor.
DEC later developed TPU
, a powerful language for designing text editors on its VMS
systems. TPU was used to produce a new standard text editor, EVE, as well as to rewrite EDT. EVE included an emulator of the EDT screen mode keypad for the benefit of those who were used to particular key functions. Both EVE and the TPU implementation of EDT are still distributed with OpenVMS
.
running on the Unisys
VS/9
operating system
using the UNIVAC 90/60
series mainframe computer
. Other than the fact that coincidentally they both had the same name, the programs were in no way similar, and that editor was not the same as the one made by Digital.
The Univac EDT editor was a line-based editor, in that it did not use function keys. Unlike editors such as Teco
or Emacs
, the program is always in text-entry mode, similar to today's word processors. Even if line numbers were not present in the original file, the editor supplied a pseudo-line number for use in editing each line. Because of the ISAM
file format which supported an 8-character index key, line numbers consisted of a floating-point number in the range of 0.000 to 9999.9999. The usual line number supplied by EDT started at 1.000 and incremented by 1 as a new line was added. Lines could be inserted between other lines by using a fractional number. A renumber command was available to renumber all or part of the file.
Commands were sent to the editor by typing in text in the same manner as entering regular text, but the first character of the line (other than a space) was the at sign ("@"). When a line began with an @, the remainder of the line was used as a text-editing command. To enter a line of text beginning with @ which was not an editor command, it was necessary to prefix the line with a second @ sign, in which case, the first @ would be stripped off, and the line taken as text rather than a command. It was also possible to issue a command that the @ sign command indicator be changed to a different character. One use for this feature would be to write scripts to have EDT perform various actions upon another file. The command set of the editor included the ability to create unattended programmable editing sessions through the use of test, comparison, branch and looping functions.
Commands in EDT generally consisted of a command (which is case insensitive), which may be followed by a range of line numbers that the command was to act upon, and a subfunction indicating how the command was to act. The range was either expressed as a single line number, a range of lines separated by a dash, (e.g. 5-8 would mean any line numbered 5.0000 through 8.9999 inclusive), or a group of lines, each separated by a comma. Some symbols were available to represent various values, such as the ampersand
"&" or the word "all" representing every line in the file.
For example, to alter every "To" in a document to the word "From" you would type in
@ON ALL CHANGE "To" TO "From"
or
@on & change "To" to "From"
followed by the transmit key (equivalent to Enter on a PC), and the editor would perform the action. Editing was basically full-screen, with actions not taking place until the user pressed the transmit key, a procedure very similar to today's practice of entering text into an input box in a web page, with no action being taken until the user clicks on the submit
button.
Univac's EDT editor provided extremely powerful editing capabilities, including
Digital
EDT was a text editorText editor
A text editor is a type of program used for editing plain text files.Text editors are often provided with operating systems or software development packages, and can be used to change configuration files and programming language source code....
that was developed by Digital Equipment Corporation
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
(DEC) for use on its PDP-11
PDP-11
The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...
series of computers (including RSX-11
RSX-11
RSX-11 is a family of real-time operating systems mainly for PDP-11 computers created by Digital Equipment Corporation , common in the late 1970s and early 1980s. RSX-11D first appeared on the PDP-11/40 in 1972...
, RSTS/E
RSTS/E
RSTS is a multi-user time-sharing operating system, developed by Digital Equipment Corporation , for the PDP-11 series of 16-bit minicomputers. The first version of RSTS was implemented in 1970 by DEC software engineers that developed the TSS-8 time-sharing operating system for the PDP-8...
and RT-11
RT-11
RT-11 was a small, single-user real-time operating system for the Digital Equipment Corporation PDP-11 family of 16-bit computers...
), and later for its VAX
VAX
VAX was an instruction set architecture developed by Digital Equipment Corporation in the mid-1970s. A 32-bit complex instruction set computer ISA, it was designed to extend or replace DEC's various Programmed Data Processor ISAs...
/VMS series as well.
The editor contained both line mode commands and a screen based editor. In screen mode, the default action for the user was to directly update text as he or she typed, with special commands available by pressing keypad commands. Arrow keys allowed for simple navigation, while keypad commands allowed for more complex navigation and searches. As with many user interfaces developed around this time, EDT used the "Gold Key" style of input first developed for the WPS-8
WPS-8
WPS-8 was the name of a Word Processing System sold by Digital Equipment Corporation for use with their PDP-8 processors ....
word processing system. "Gold Key" editing used the PF1 keypad key as a meta key
Meta key
The meta key is a special key on MIT keyboards, such as the space-cadet keyboard, and on Sun Microsystems keyboards, marked as a solid diamond.The key is similar in function to the Macintosh's command key, which has the same location...
allowing the introduction of a wide variety of commands using both the keypad keys and keys on the main keyboard. Pressing the PF2 keypad key would give on-screen help on the keypad and other key combinations:
/-----------------------------------\ /-----------------------------------\
| ^ | DOWN | | | | | | FNDNXT | DEL L |
| | | | | <---- | ----> | | GOLD | HELP | | |
| | | | | LEFT | RIGHT | | | | FIND | UND L |
| UP | v | | | |--------+--------+--------+--------|
\-----------------------------------/ | PAGE | SECT | APPEND | DEL W |
DELETE Delete character | | | | |
LINEFEED Delete to beginning of word | COMMAND| FILL | REPLACE| UND W |
BACKSPACE Backup to beginning of line |--------+--------+--------+--------|
CTRL/A Compute tab level | ADVANCE| BACKUP | CUT | DEL C |
CTRL/D Decrease tab level | | | | |
CTRL/E Increase tab level | BOTTOM | TOP | PASTE | UND C |
CTRL/K Define key |--------+--------+--------+--------|
CTRL/R Refresh screen | WORD | EOL | CHAR | |
CTRL/T Adjust tabs | | | | ENTER |
CTRL/U Delete to beginning of line |CHNGCASE| DEL EOL| SPECINS| |
CTRL/W Refresh screen |-----------------+--------| |
CTRL/Z Exit to line mode | LINE | SELECT | |
| | | SUBS |
Press a key for help on that key. | OPEN LINE | RESET | |
To exit, press the spacebar. \-----------------------------------/
Users could configure default actions or define key sequences for their editor by placing EDT commands in an initialization file which would be executed upon starting the editor.
DEC later developed TPU
Text Processing Utility
DEC Text Processing Utility was a language developed by Digital Equipment Corporation for developing text editors. In 1986, DEC developed a new version of EDT written in DECTPU. DECTPU is distributed with OpenVMS...
, a powerful language for designing text editors on its VMS
OpenVMS
OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...
systems. TPU was used to produce a new standard text editor, EVE, as well as to rewrite EDT. EVE included an emulator of the EDT screen mode keypad for the benefit of those who were used to particular key functions. Both EVE and the TPU implementation of EDT are still distributed with OpenVMS
OpenVMS
OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...
.
Univac
EDT was also the name of the text editorText editor
A text editor is a type of program used for editing plain text files.Text editors are often provided with operating systems or software development packages, and can be used to change configuration files and programming language source code....
running on the Unisys
Unisys
Unisys Corporation , headquartered in Blue Bell, Pennsylvania, United States, and incorporated in Delaware, is a long established business whose core products now involves computing and networking.-History:...
VS/9
VS/9
VS/9 was a computer operating system available for the Univac 90/60, 90/70 and 90/80 mainframe during the late 1960s through 1980s. The 90/60 and 90/70 were repackaged Univac 9700 computers...
operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
using the UNIVAC 90/60
UNIVAC 90/60
The Univac 90/60 series computer was a mainframe class computer manufactured by Sperry Corporation as a competitor to the IBM System 360 series of mainframe computers...
series mainframe computer
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...
. Other than the fact that coincidentally they both had the same name, the programs were in no way similar, and that editor was not the same as the one made by Digital.
The Univac EDT editor was a line-based editor, in that it did not use function keys. Unlike editors such as Teco
Text Editor and Corrector
TECO is a text editor originally developed at the Massachusetts Institute of Technology in the 1960s, after which it was modified by 'just about everybody'...
or Emacs
Emacs
Emacs is a class of text editors, usually characterized by their extensibility. GNU Emacs has over 1,000 commands. It also allows the user to combine these commands into macros to automate work.Development began in the mid-1970s and continues actively...
, the program is always in text-entry mode, similar to today's word processors. Even if line numbers were not present in the original file, the editor supplied a pseudo-line number for use in editing each line. Because of the ISAM
ISAM
ISAM stands for Indexed Sequential Access Method, a method for indexing data for fast retrieval. ISAM was originally developed by IBM for mainframe computers...
file format which supported an 8-character index key, line numbers consisted of a floating-point number in the range of 0.000 to 9999.9999. The usual line number supplied by EDT started at 1.000 and incremented by 1 as a new line was added. Lines could be inserted between other lines by using a fractional number. A renumber command was available to renumber all or part of the file.
Commands were sent to the editor by typing in text in the same manner as entering regular text, but the first character of the line (other than a space) was the at sign ("@"). When a line began with an @, the remainder of the line was used as a text-editing command. To enter a line of text beginning with @ which was not an editor command, it was necessary to prefix the line with a second @ sign, in which case, the first @ would be stripped off, and the line taken as text rather than a command. It was also possible to issue a command that the @ sign command indicator be changed to a different character. One use for this feature would be to write scripts to have EDT perform various actions upon another file. The command set of the editor included the ability to create unattended programmable editing sessions through the use of test, comparison, branch and looping functions.
Commands in EDT generally consisted of a command (which is case insensitive), which may be followed by a range of line numbers that the command was to act upon, and a subfunction indicating how the command was to act. The range was either expressed as a single line number, a range of lines separated by a dash, (e.g. 5-8 would mean any line numbered 5.0000 through 8.9999 inclusive), or a group of lines, each separated by a comma. Some symbols were available to represent various values, such as the ampersand
Ampersand
An ampersand is a logogram representing the conjunction word "and". The symbol is a ligature of the letters in et, Latin for "and".-Etymology:...
"&" or the word "all" representing every line in the file.
For example, to alter every "To" in a document to the word "From" you would type in
@ON ALL CHANGE "To" TO "From"
or
@on & change "To" to "From"
followed by the transmit key (equivalent to Enter on a PC), and the editor would perform the action. Editing was basically full-screen, with actions not taking place until the user pressed the transmit key, a procedure very similar to today's practice of entering text into an input box in a web page, with no action being taken until the user clicks on the submit
Submission
Submission is the acknowledgement of the legitimacy of the power of one's superior or superiors.Submission may also refer to:* Submission/Submitter , an Islamic organisation...
button.
Univac's EDT editor provided extremely powerful editing capabilities, including
- text formatting similar to RunoffRunoff (program)runoff was the text formatting program on the Multics operating system.It was a descendant of the RUNOFF type-setting program from CTSS and was originally written by Jerome H. Saltzer...
(in which commands were given for text editing by preceding lines with a period) - possibly one of the first programs (the Univac 90/60 goes back to the late 1960s and early 1970s) to support the use of plugins to allow other programs to use the text the editor held in memory, as well as send commands back to the editor for processing.
- sort
- search
- editing of plain text and files with line numbers
- direct on-disk editing of files too large to hold in memory