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1986-01-14
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1,099 lines
Users Manual For
DED
Version 2.00
A full-screen text editor for DEC Rainbow computers
Written by Dan Pleasant
Lower Falls Software
Newton, MA
(C) Copyright 1985,1986
TABLE OF CONTENTS
=================
Disclaimer . . . . . . . . . . . . . . . . . . . . . . . 1
Introduction . . . . . . . . . . . . . . . . . . . . . . 2
Getting Started . . . . . . . . . . . . . . . . . . . . 2
The First Few Steps . . . . . . . . . . . . . . . . . . 3
Finding and Replacing strings of text . . . . . . . . . 7
Block Operations . . . . . . . . . . . . . . . . . . . . 9
File Insertion . . . . . . . . . . . . . . . . . . . . . 10
User-Defineable Keys (Macros) . . . . . . . . . . . . . 11
Control Characters . . . . . . . . . . . . . . . . . . . 12
Foreign Language Characters . . . . . . . . . . . . . . 12
Printing . . . . . . . . . . . . . . . . . . . . . . . . 14
Cancelling a Command . . . . . . . . . . . . . . . . . . 15
Exiting to MS-DOS . . . . . . . . . . . . . . . . . . . 15
Additional Options . . . . . . . . . . . . . . . . . . . 15
Other Functions . . . . . . . . . . . . . . . . . . . . 16
Editing Very Large Files . . . . . . . . . . . . . . . . 17
i
Disclaimer
==========
DED is a copyrighted program. It is available as
"freeware" for non-commercial use only. DED may not be copied
or sold for any commercial purpose whatsoever except by the
owner of the copyright or his legal representative.
Commercial companies may contact the author for licensing
information.
No warranty of any sort whatsoever is supplied with DED.
Whew!! Now that the pseudo-legal mumbo-jumbo is over
with, we can get down to the good stuff.
DED is a fairly mature product, having been in
widespread use for well over a year now, and most of the bugs
have been worked out. However, any large program is likely to
contain bugs. If you find any, and if you can successfully
document them, please contact the author through FIDO net
number 101, node number 202, at (617) 721-1688.
Your friendly programmer would like to take time now
for a commercial message. DED is a fully functional editor,
and as such, it could be worth as much as $200 on the open
market. DED is supplied free to private individuals who want
it. However, if you like the program, and if you use it,
PLEASE help a starving programmer by sending $25.00 to the
address below. This will allow two things to happen. First,
the extra cash will allow me to continue development of the
program, as well as keeping my enthusiasm at a high level.
Second, those who send money will get questions answered and
bugs fixed. Those who do not will be ignored.
Send checks to:
Dan Pleasant
153 Concord St., #16
Newton, MA 02162
Thanks!!!
DED is written in assembly language, so it would be
fairly difficult anyone but the original author to make
additions to the program. However, should anyone think that
they're up to it, the source code is available (for a
fairly large price). Contact the author for further
information.
1
Introduction
============
DED is a sophisticated, high performance text editor for
use with DEC Rainbow computers. It is not a word processor,
but a program-oriented text editor with cut-and-paste
abilities. It runs under MS-DOS, and is intended to fill the
void caused by the absence of good, fast, full-function
editors for the Rainbow.
DED's features include 4 cut-and-paste buffers,
auto-indenting, 24 user-defineable keys, unlimited file size,
and block move/find/delete operations. All commands are
executed in 1 or 2 keystrokes using the Rainbow's function
keys. There is no limitation on file size other than the
capacity of the mass storage device. DED is also written
completely in assembly language and takes advantage of many
of the Rainbow's advanced features, which makes it incredibly
fast.
DED requires 256 Kbytes of RAM and MS-DOS 2.0 or higher.
It uses three temporary files for virtual memory operations.
Getting Started
===============
To begin the program, simply type
DED
and hit the <Return> key. This will cause DED to load itself
into memory and reserve memory space for your input. To
edit an existing file, type
DED filename
and hit the <Return> key. This will cause DED to load
itself, and then load the specified file for editing. The
top 22 lines of your file will appear on the screen, with
the cursor positioned at the first character.
If an error occurs during loading, DED will print an
error message and halt. This can happen if:
There is less than 256 Kbytes of memory
in your Rainbow.
There is not enough room on the default
disk for DED to create the temporary
files it needs.
2
You specified a file that DED cannot
read. This can be caused by specifying
the name of a file that is zero bytes
long, or by specifying an illegal file
name.
Once DED is loaded, the top 22 lines of the screen will
be used for editing. There will be a solid line in line
23, and the bottom line is maintained by DED as a "status"
line. The status line is used by DED for communication with
the user. The "Insert Mode" status always appears at the
end of the status line in reverse video. This will always say
"Insert ON" or "Insert OFF". Just before this is the name of
the file you are editing. If no file name is listed here, you
must specify one before you can save your file.
A new feature of DED, version 2.0, is the line and
column number notation at the far left of the status
line. The cursor line and column number will always appear
here.
All commands in DED are initiated by pressing one of the
Rainbow's special function keys. Different commands can be
specified by holding the <Shift> or <Ctrl> keys while
pressing a function key. To see what any individual key does,
press <Help> and then the function key. DED will clear the
screen and print a brief explanation of that key's three
possible functions. Not every possible keystroke executes a
command, however. If you press a key that does nothing, the
computer will just beep.
By the way, you should also press <Shift>-<Help>
and read the message that you find there.
It is probably possible to discover all of DED's
features just by pressing the HELP key and experimenting.
However, on the assumption that not everyone likes that
sort of puzzle, the following pages present a tutorial on
the care and feeding of DED.
The First Few Steps
===================
Let's suppose you have started DED as described in the
last section. You did not enter a file name, so the top
23 lines of the screen are blank, there is no file name
listed in the status line, and "Insert" is on. (Insert mode
is always on when DED is first started.)
The first thing you want to do is specify a file name,
so you can save the text you are about to type. To tell
3
DED that you want to enter a file name, press the <Main
Screen> key. (Most of the other function keys are named
more logically than this one. Unfortunately, DEC did not
see fit to include an "Enter-new-file-name" key on the
Rainbow's keyboard.) When you press <Main Screen>, the
cursor will move to the status line and the message "Enter
new file name:" will appear. At this point, you can type in
any file name you wish, including a drive specifier and a
path name if necessary. In fact, you can enter an illegal
file name here if you want to, but DED won't let you save
anything with an illegal file name. If you enter a full path
name, the string might be too long to fit in the space
provided on the status line. This makes things look funny,
but don't worry about it. Nothing bad will happen.
Now let's suppose you have entered a file name, like
"TEST.TXT". When you press the <Return> key, the cursor
will jump back to the top of the screen and the new file
name TEST.TXT will appear in the status line. Now you can
enter text.
To enter text, just type it. Anything you type now will
appear in the top 22 lines of the screen. There is virtually
no limit to the length of a line, even though the screen is
only 80 characters wide (the real limit is 1800 characters).
If you type more than 80 characters on a line, the the whole
screen will move 30 characters to the left to give you more
room to type. (This happens VERY FAST and can be a little
disconcerting the first few times it happens.) When you hit
the <Return> key, the screen will return to the beginning of
the next line. DED will scroll horizontally in this way as
many times as you need it to.
If you are using this manual as a tutorial, type in some
text now so you can practice editing it later.
Now that you have some text to work with, try using the
cursor movement keys. These keys have been defined so that if
pressing the key alone does something, holding the <Ctrl> key
does more of the same thing, and holding the <Shift> key does
even more. For instance, the "Up Arrow" key moves the cursor
up one line. Holding the <Ctrl> key while pressing the "Up
Arrow" key moves the cursor up 11 lines, and holding the
<Shift> key while pressing the "Up Arrow" key moves the
cursor all the way to the top of the screen. The four cursor
control keys are defined as follows:
<Up>: Move up 1 line
<Crtl>-<Up>: Move up 11 lines
<Shift>-<Up>: Move to the top of the screen
<Down>: Move down 1 line
4
<Crtl>-<Down>: Move down 11 lines
<Shift>-<Down>: Move to the bottom of the screen
<Left>: Move left 1 character
<Crtl>-<Left>: Move left 1 word
<Shift>-<Left>: Move to the beginning of the line
<Right>: Move right 1 character
<Crtl>-<Right>: Move right 1 word
<Shift>-<Right>: Move to the end of the line
The <Next Screen> and <Prev Screen> keys are defined
similarly. For instance, pressing <Next Screen> will move
the cursor down 22 lines. This also happens VERY FAST.
Pressing <Shift>-<Next Screen> moves the cursor to the end
of the file. <Prev Screen> moves the cursor up 22 lines,
and <Shift>-<Prev Screen> moves the cursor to the beginning
of the file.
<Ctrl>-<Next Screen> and <Ctrl>-<Prev Screen> are a
little different. The move the cursor up or down in the
file continuously until you press any key. This is useful for
scanning through a file until you find the place you are
looking for.
After you have typed in some text, try experimenting
with these keys, especially the <Next Screen> and <Prev
Screen> keys. If you are accustomed to another full-screen
editor, the speed at which DED moves to a new screen is
almost frightening.
One thing that programmers usually need to do is find a
specific line number within the file. Of course, you can just
hold down the <Down Arrow> key until you reach the line you
want, but it is much faster to use the <Resume> key. When you
press <Resume>, DED will ask you what line you want to go
to. Type in the line number, and you will be there
exceptionally quickly.
The next function key to try is the <Insert Here> key.
This key toggles DED's insertion function. The first time
you press <Insert Here>, the indication in the status line
will change to "Insert OFF", the second time it will change
to "Insert ON", and so on. If the insertion mode is OFF,
anything you type will appear "on top of" anything that was
already there. If the insertion mode is ON, anything that has
already been entered will move to the right to make room for
the new text. Try experimenting with this for a while until
you see how it works.
If you make a mistake, DED supplies a truly frightening
variety of ways to erase your error, from deleting a single
5
character to erasing the entire file. The basic key to use is
the <Remove> key. <Remove> won't erase more than a line full
of characters at a time, so it is fairly safe to use. It is
defined as follows:
<Remove>: Remove 1 character
<Crtl>-<Remove>: Remove 1 word
<Shift>-<Remove>: Remove 1 line
This is all fairly benign. Now let's suppose you made a
REALLY big mistake, and you want to erase a lot of text. The
<F4> key is one way to handle this. <F4> is defined as
follows:
<F4>: Erase everything from the cursor to the
end of the file
<Crtl>-<F4>: Erase everything from the beginning
of the file to the cursor
<Shift>-<F4>: Erase the entire file
Another method of selectively deleting large blocks of
text is discussed later, in the "Block Operations" section.
You can also delete specific strings of text by using the
<Shift>-<Find> or <Shift>-<Addtnl Options> keys, as described
in the next section.
Now you should be able to enter, change and delete text,
and to move the cursor around at will. The next question
is, how do you save it?
There are 2 ways to save your file, and both of them are
initiated by pressing the <Exit> key. If you press
<Shift>-<Exit> your file will be saved and DED will return
control to MS-DOS. If you press <Exit> without holding the
<Shift> key, DED will save your file and return, allowing you
to make further changes. In both cases, a backup file is
maintained on the disk with a ".BAK" extension. If the disk
fills up, DED will tell you so. If this happens you should
use the <Main Screen> key to rename the file, only this time
you should specify another disk. DO NOT remove the default
disk because DED keeps its temporary files there.
If you decide that you are completely dissatisfied with
everything you have done so far, you can press the <Cancel>
key. This will cause DED to return control to MS-DOS without
saving any changes you may have made. (DED will ask you for
verification before it halts, just in case you pressed
<Cancel> by accident.)
The commands discussed so far are enough to allow you to
create, edit and save text files. However, DED (like all
other text editors) includes features that allow much
6
greater flexibility in file and text menipulation. These are
covered in detail in the next sections.
Finding and Replacing strings of text
=====================================
As you might expect, the <Find> key causes the computer
to find any string of text. This saves you a lot of time and
eye-strain. The <Find> key is defined as follows:
<Find>: Find a string that you specify
<Crtl>-<Find>: Find the same string again
<Shift>-<Find>: Find a string and replace it with
another string
If you press <Find>, DED will print an arrow in the
status line followed by the message "Find what?". The arrow
represents the direction the search will be made in. If the
arrow points to the right, DED will search from the cursor
position to the end of the file. If it points to the left,
DED will search in the opposite direction. At this point, you
can type the string you want to find. You can enter up to 200
characters. If you want to search in the opposite direction,
press any of the four cursor movement keys. Pressing "left"
or "up" causes DED to search backwards, and pressing "right"
or "down" causes DED to search forward. When you press the
<Return> key DED will find the string you entered, if it
exists. If not, the cursor will return to wherever it was
before you pressed the <Find> key.
If you press <Crtl>-<Find>, DED will try to find to same
string again. If you have never pressed <Find> and entered a
string, pressing <Crtl>-<Find> will not do anything.
<Crtl>-<Find> does not allow you to change the direction of
the search.
If you want to replace a string with another string,
press <Shift>-<Find>. DED will prompt you for a string to
search for, and then it will ask you "Replace with what?".
Enter the string with which you want to replace the first
string. To delete the first string entirely, just press
<Return> without entering anything. You can change the
direction of the search at any time, as before. After you
enter the replacement string, DED will ask you how many
times you want to do the replacement. The default is 1, and
the maximum is 65537. Then DED will ask if you want to
confirm each replacement before it is made. Press "Y", "N",
<Break>, or <Return>. <Break> cancels the command entirely,
and <Return> takes the default. The default is "Y" the first
time you use <Shift>-<Find>. After that, the default is
whatever you entered the last time.
7
The <Find> key finds what you are looking for VERY
quickly, but it has a few limitations. For instance, you
cannot search for a tab character because DED changes all
tabs to spaces. And sometimes you will want to search for a
string that looks like "AxBCD", where "x" can be "anything
except an A" or maybe "any series of spaces, no matter how
long". Furthermore, the <Find> key is case-sensitive, meaning
that you have to know if the string you are searching for is
upper-case or lower-case. Version 2.0 of DED solves this
problem through the <Addtnl Options> key.
Pressing the <Addtnl Options> key allows you to use a
wide variety of wild-card characters when searching for a
string. When you press <Addtnl Options>, DED will prompt you
with "Find What?" in the status line, exactly as it did when
you pressed the <Find> key. This time, however, DED will
allow you to use the <Select> key while you are typing the
string you want to search for. The <Select> key tells DED
that you are going to use a wild card character in this
search. To see what all the possible wild cards are, you can
press the <Help> key after you press the <Addtnl Options>
key. All of the wild cards are two- or three-key sequences,
starting with the <Select> key, as in the table below:
<Select>-X Accept ANY character as a match
<Select>-A Accept any alphabetic character
<Select>-1 Accept any digit
<Select>-N Accept any alphanumeric character
<Select>-<ESC> Accept any non-alphanumeric
character
<Select>-~ Accept any character from the DEC
extended character set
<Select>-L Accept any lower-case alphabetic
character
<Select>-U Accept any upper-case alphabetic
character
<Select>-<Space> Accept any string of spaces and/or
tabs
<Select>-<Select>-x Accept any character EXCEPT "x"
When you enter a wild card character, it will appear in
boldface on the screen. If you use the last wild card in the
list above (<Select>-<Select>-x), the whatever character you
enter for "x" will appear in reverse video instead of bold.
Wild card characters can be entered anywhere in the
string, including the first character. Furthermore, a search
that is started with the <Addtnl Options> key is NOT
case-sensitive. This makes the search routine very flexible.
The <Shift>-<Addtnl Options> and <Ctrl>-<Addtnl Options>
8
keys are defined analogously with the <Find>
key. <Crtl>-<Addtnl Options> finds the same string (including
wild cards) again, and <Shift>-<Addtnl Options> finds a
string and replaces it with another. (You cannot put wild
cards in the replacement string.) Additionally, the <Find>
and <Addtnl Options> keys are completely separate. You can
set them up so that one key searches forward and the other
backward, if you wish.
Why are there two separate ways to search in DED? There
are two reasons. First, the <Find> key's routine is
blindlingly fast when compared to the <Addtnl Options>
key. Second, the <Find> key is easier to use in many cases,
because you don't have to worry about wild cards. This makes
the <Find> key the one to use unless you really need the
extra flexibility allowed by the <Addtnl Options> key.
Block Operations
================
One of the best features of any good text editor is the
ability to move and delete selected blocks of text. DED uses
two different function keys for this purpose: <Select> and
<Do>.
The <Select> key defines the beginning of a block. Just
move the cursor to the first line in the block you want to
define and press <Select>. Nothing will visibly happen until
you define the end of the block. To do this, go to the end
of the block and press <Ctrl>-<Select>. (You can press
<Select> and <Crtl>-<Select> in either order.) When you have
defined both a beginning and an end of a block, the entire
block will appear in reverse video. (If you decide you want
to "un-define" the block, press <Shift>-<Select>.) Now you
can use this block of text in any of several ways.
The <Do> key is used as a prefix for block operations.
If you press <Do> before you have defined a block, the
computer will beep. You must define a block using the
<Select> key before the <Do> key will function. Assuming you
have already defined a block, pressing the <Do> key will
cause DED to ask "Do what?" in the status line. Now you can
press any of several keys, which are:
<Help> Prints a list of options.
<Print Screen> Sends the block to the printer.
<Find> Moves the cursor to the beginning of
the block.
9
<Remove> Deletes the entire block.
<Insert Here> Copies the block to the cursor
location.
<PF1> Saves the block in a disk file
called "BUFFER1.DED".
<PF2> Saves the block in a disk file
called "BUFFER2.DED".
<PF3> Saves the block in a disk file
called "BUFFER3.DED".
<PF4> Saves the block in a disk file
called "BUFFER4.DED".
The <PF1..4> keys have a dual function. If you press
<Shift>-<PF1..4>, DED will overwrite anything that was
previously written to the buffer file. If you don't hold the
<Shift> key, DED will append the block of text to the end of
whatever was already in the file. The BUFFERn.DED files can
be inserted elsewhere in your file or into another file
through use of the <Crtl>-<Insert Here> key, which is
explained more fully in the next section. Normally, DED will
erase these four files when you quit. However, one of the
options you can set by pressing the <Shift>-<Main Screen> key
allows you to tell DED to save them instead. You can also
make DED save them by default, by setting an environment
variable. This is described fully in the section on
"Additional Options".
There are a few limitations on the use of blocks. First,
blocks can only be made up of complete lines -- you cannot
make a block begin or end in the middle of a line. Second, a
few operations (notably the <Shift>-<Insert Here>,
<Crtl>-<Insert Here>, <F4>, <Shift>-<F4> and <Crtl>-<F4>
keys) will automatically un-define any block that you have
defined. Also, certain virtual memory operations can cause a
block definition to be lost. If this happens, a warning
message will appear. However, virtual memory operations are
seldom necessary except in files larger than about 55K-bytes
or so, and even then it is very rare for a block to be
un-defined.
File Insertion
==============
As you saw briefly in the last section, pressing <Crtl>-
<Insert Here> allows you to insert one of the buffer files
BUFFER1.DED, BUFFER2.DED, BUFFER3.DED or BUFFER4.DED. DED
10
will ask you which of the four files you wish to insert, and
you answer by pressing PF1, PF2, PF3 of PF4. If the file you
selected does not exist in the current directory, DED will
print an error message. Note that you can transfer data
between different files by this method.
You can also insert a file other than one of the buffer
files. Pressing <Shift>-<Insert Here> causes DED to ask you
for a file name. You can enter any legal file name, including
a drive specifier and a path name if necessary. If DED cannot
find the file, an error message will appear. Otherwise, the
file will be inserted to the cursor position.
User-Defineable Keys (Macros)
=============================
The <F17>, <F18>, <F19>, <F20>, <PF1>, <PF2>, <PF3>,
and <PF4> keys, and <Shift> and <Crtl> combinations of
them, are all user-defineable keys. This allows a total of
24 possible macros. Macros in DED can include any combination
of keystrokes, including function keys AND ILLEGAL
KEYSTROKES. No error checking is done during the definition
of a macro. Macros can be used to enter text, to "press" any
function key, or to answer any prompt. In fact, it is
possible to define a macro that defined itself, but this is
not recommended and will probably hang up the computer. The
user-defineable keys are intended to be as flexible as
possible, but this flexibility can sometimes be dangerous.
If you press a macro key that has not been defined, the
computer will just beep. To define a macro, press <Crtl>-<Do>
and then press the key you wisk to define. DED will prompt
you in the status line. You can enter up to 50 keystrokes in
the definition of a macro. If you press a function key or an
illegal key, a funny character will appear. Don't worry about
it. This is just DED's way of telling you that you have
entered something other than an alphanumeric character. To
end the macro definition, press <Crtl>-<Return>.
(<Crtl>-<Return> is used here so that you can enter <Return>
as part of the macro.)
After a key has been defined you just have to press it
again to execute the new macro. If you pressed a function
key during the macro definition, that key's function will
be executed. Any alphanumeric characters will be entered
just as though you had typed them yourself.
DED also allows you to save your macro definitions on
disk. Pressing <Shift>-<Do> causes DED to store them on the
default disk in the file MACROS.DED. If this file exists, DED
will overwrite whatever is in it. When DED initializes itself
11
it looks for this file and, if it exists, uses it to define
the macro keys. Otherwise, all 24 macros will be undefined
until you use <Crtl>-<Do> to define them.
Control Characters
==================
DED allows only 4 control characters to be inserted in a
file. Pressing the <F11>, <F12>, or <F13> keys enters,
respectively, escape, backspace, and linefeed. Pressing
<Shift>-<F13> enters a form feed.
If DED encounters a control character other than one of
these in a file, it changes it to a space. The only
exceptions are the TAB character and <Crtl>-Z.
By default, tab characters are usually expanded to
fields of 8 spaces. DED tries to handle tab settings in a
semi-intelligent way. When you start DED, the tab setting
will be 8 spaces UNLESS you have entered a file name that
ends with ".C" or ".PAS". If the file extension is ".C" or
".PAS", then the tab setting will be automatically be set to
4 spaces. This is generally convenient for programmers. If
you want to set the tab stops yourself, you can use the
<Shift>-<Main Screen> key to do so, and you can create an
environment variable that will change DED's default
values. See the section on "Additional Options" for better
instructions.
<Crtl>-Z is interpreted as end-of-file. This is
consistent with the CP/M convention. Since a fairly large
number of MS-DOS programs were converted from CP/M, DED also
appends a <Crtl>-Z to the end of the file to accommodate any
other program that may expect it.
Foreign Language Characters
===========================
DED allows you to insert DEC 8-bit multinational
characters in your file. If you have a Rainbow 100-B, which
does directly supports the <Compose Character> key, all you
have to do is press <Compose Character> followed by the usual
key sequence for whatever character you want. If you have a
Rainbow 100-A, which does not support the <Compose Character>
key, press <Compose Character> followed by any other
alphanumeric key to access the special characters. DED will
insert a character into your file according to the following
table.
You Press To Get
a
b
12
c
d
e
f
g
h
i
j
k
l
m
n
o
p not allowed
q
r
s
t
u
v
w
x
y
z
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P not allowed
Q
R
S
T
U
V
W
X
Y
Z
1
2
13
3
4 not allowed
5
6
7
8 not allowed
9
0
!
@
#
$ not allowed
%
^ not allowed
*
(
)
This arrangement is not consistent with the <Compose
Character> function as implemented by DEC on the Rainbow
100B. It does not seem to be a problem, however. Note that if
you have the extended character ROM in your Rainbow, the
characters that you get will not be the same.
Printing
========
DED allows you to print all or part of a file at any
time. If you press <Print Screen>, DED will do just that.
To print the whole file, press <Shift>-<Print Screen>. To
print any part of a file, define that part of the file as a
block, then press <Do> and <Print Screen>.
By default, DED will send a form feed character to the
printer at the end of each page. This will work fine if you
own a printer that uses pin-fed sheets of paper, like the DEC
LA-50. However, some people may own printers that do not
respond to form feeds or that only take one sheet of paper at
a time. If you own such a printer, use the <Shift>-<Main
Screen> key to tell DED not to send form feeds. When you
press <Shift>-<Main Screen>, one line that appears on
the screen will say "Pause each page while printing". If you
set this option to "Yes", DED will pause after it prints a
page and wait for you to insert a new sheet of paper. When
the paper is inserted, press any key to resume printing.
While DED prints a special character on the screen for
each of the four allowable control characters, it will
send the actual character to the printer. This allows
you to create special printer functions by inserting escape
codes into your file, and then testing them on your printer
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without exiting DED.
To abort printing at any time, press any key. Printing
may not cease for a second or two if the computer is waiting
for the printer to drop its XOFF signal or if you have a
large printer buffer.
Cancelling a Command
====================
You can terminate any command by pressing the <Break>
key if DED is asking for keyboard input. Press <Break>
if you have started a command (such as <Find>) and you
decide that you don't want that command to continue. The
cursor will return to the main screen, and the command will
abort.
Exiting to MS-DOS
=================
Besides using the <Shift>-<Exit> key to exit DED, you
can execute MS-DOS commands by using the <Interrupt> key. If
you press <Interrupt>, DED will attempt to run COMMAND.COM.
If COMMAND.COM cannot be found, DED will print an error
message. If COMMAND.COM exists, DED will temporarily exit to
MS-DOS. However, the status line will remain on the screen as
a reminder that DED is still active. To return to DED, type
"EXIT" at the MS-DOS command level.
If you use <Interrupt> to enter MS-DOS and then print a
directory of the current disk, you will see the three files
that DED uses for virtual memory operations. DO NOT ERASE
THESE FILES. If you are using any of the four BUFFERn.DED
files, do not erase them either. DED will not be able to
properly close the files if you erase them, and you will
probably lose a portion of your data.
Additional Options
==================
The <Shift>-<Main Screen> key allows you to toggle four
of DED's less-often used functions. these are "Tab Setting",
"Save Buffer Files", "Auto-Indent" and "Pause Before
Printing". When you press the <Shift>-<Main Screen> key these
options are listed on the screen, followed by either "Yes" or
"No", except for "Tab Setting" which is either 4 or 8. The
first three are set to "No" by default when DED starts
up. Tab settings are set as described in the "Control
Characters" section above.
To set any of these functions, type "Y" or "N" (or "4"
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or "8") when the cursor is at the appropriate spot. <Return>
moves the cursor to the next option without changing the
current one, and <Break> cancels the command.
If "Save Buffer Files" is set to "Yes", DED will not
erase the four files BUFFERn.DED (n=1,2,3,4). Note that
these files are not created unless you use the <Do> <PF1..4>
sequence to do so.
If "Auto-Indent" is set to "Yes", DED will automatically
indent the cursor each time you type <Return> while entering
text. The cursor will be indented to the same depth as the
preceeding line.
If "Pause Before Printing" is set to "Yes", DED will
pause at the end of each page while printing a document to
allow you file put in another sheet of paper.
You can set the default values of any of these four
functions by using environment variables. When DED starts up,
it looks for four environment variables:
DEDIND sets the auto-indent feature. You should set
either DEDIND=Y or DEDIND=N.
DEDBUF tells DED whether or not to save the BUFFERn.DED
buffer files. Set DEDBUF=Y or DEDBUF=N.
DEDPAG sets the "pause while printing" feature. Set
DEDPAG=Y or DEDPAG=N.
DEDTAB sets the tab setting. Set DEDTAB=4 or DEDTAB=8.
If DED finds any of these four variables when it starts
up, it sets the default accordingly. For instance, if you
want to use tab stops in columns of 4 all the time, type
SET DEDTAB=4
at the MS-DOS command level before you start DED. Then all
tabs will be expanded in columns of 4 spaces. You can still
change the tab setting at any time by using the <Shift>-<Main
Screen> key.
Other Functions
===============
For those of you who, like the author, tend to transpose
characters, the <Crtl>-<Compose Character> and
<Shift>-<Compose Character> keys may be of some
use. NOTE: These functions ONLY operate on Rainbow 100-A
computers.
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<Crtl>-<Compose Character> will swap the last two
letters you have typed. <Shift>-<Compose Character> will
swap the last two lines.
Editing Very Large Files
========================
Theoretically, there is no limit to file size when using
DED. However, the usual disk size rules apply, with a couple
of caveats related to "virtual memory".
When you edit a file, DED will attempt to read the
entire file into memory. Most files will fit with no problem
since DED uses a 64K-byte buffer. (Allowing for overhead,
this allows DED to completely read any file up to about 55
Kbytes.) For longer files, DED uses 3 temporary files in the
current default directory. One of these files is always
empty. However, the other two contain that part of the file
that DED could not put into memory. These files are swapped
into memory as needed during the editing session.
A problem may occur when the disk drive fills up while
DED is swapping the files. There is a point during this
time when DED cannot recover if the disk fills up. If this
happens, DED will print an error message and exit. This
problem is easy to avoid, and there are several obvious
ways of doing so. If you rarely fill up a disk you will
probably never encounter the problem. In fact, in all the
time DED has been in use this problem has never been
encountered by anyone.
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