[Emacs-diffs] Changes to msdog-xtra.texi

[Glenn Morris]

CVSROOT:        /sources/emacs
Module name:    emacs
Changes by:     Glenn Morris <gm>       07/09/06 04:47:45

Index: msdog-xtra.texi
===================================================================
RCS file: msdog-xtra.texi
diff -N msdog-xtra.texi
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ msdog-xtra.texi     6 Sep 2007 04:47:45 -0000       1.1
@@ -0,0 +1,687 @@
address@hidden This is part of the Emacs manual.
address@hidden Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, 
Inc.
address@hidden See file emacs.texi for copying conditions.
address@hidden
address@hidden This file is included either in emacs-xtra.texi (when producing 
the
address@hidden printed version) or in the main Emacs manual (for the on-line 
version).
address@hidden MS-DOS
address@hidden Emacs and MS-DOS
address@hidden MS-DOG
address@hidden MS-DOS peculiarities
+
+  This section briefly describes the peculiarities of using Emacs on
+the MS-DOS ``operating system'' (also known as ``MS-DOG'').
address@hidden
+Information about Emacs and Microsoft's current operating system
+Windows (also known as ``Losedows) is in the main Emacs manual
+(@pxref{Microsoft Systems,,, emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
+Information about peculiarities common to MS-DOS and Microsoft's
+current operating systems Windows (also known as ``Losedows) is in
address@hidden Windows}.
address@hidden ifnottex
+
+  If you build Emacs for MS-DOS, the binary will also run on Windows
+3.X, Windows NT, Windows 9X/ME, Windows 2000/XP, or OS/2 as a DOS
+application; all of this chapter applies for all of those systems, if
+you use an Emacs that was built for MS-DOS.
+
address@hidden
+  @xref{Text and Binary,,,emacs, the Emacs Manual}, for information
address@hidden iftex
address@hidden
+  @xref{Text and Binary}, for information
address@hidden ifnottex
+about Emacs' special handling of text files under MS-DOS (and Windows).
+
address@hidden
+* Keyboard: MS-DOS Keyboard.   Keyboard conventions on MS-DOS.
+* Mouse: MS-DOS Mouse.         Mouse conventions on MS-DOS.
+* Display: MS-DOS Display.     Fonts, frames and display size on MS-DOS.
+* Files: MS-DOS File Names.    File name conventions on MS-DOS.
+* Printing: MS-DOS Printing.   Printing specifics on MS-DOS.
+* I18N: MS-DOS and MULE.       Support for internationalization on MS-DOS.
+* Processes: MS-DOS Processes. Running subprocesses on MS-DOS.
address@hidden menu
+
address@hidden MS-DOS Keyboard
address@hidden Keyboard Usage on MS-DOS
+
address@hidden DEL @r{(MS-DOS)}
address@hidden BS @r{(MS-DOS)}
+  The key that is called @key{DEL} in Emacs (because that's how it is
+designated on most workstations) is known as @key{BS} (backspace) on a
+PC.  That is why the PC-specific terminal initialization remaps the
address@hidden key to act as @key{DEL}; the @key{DELETE} key is remapped to act
+as @kbd{C-d} for the same reasons.
+
address@hidden C-g @r{(MS-DOS)}
address@hidden C-BREAK @r{(MS-DOS)}
address@hidden quitting on MS-DOS
+  Emacs built for MS-DOS recognizes @address@hidden as a quit
+character, just like @kbd{C-g}.  This is because Emacs cannot detect
+that you have typed @kbd{C-g} until it is ready for more input.  As a
+consequence, you cannot use @kbd{C-g} to stop a running command
address@hidden
+(@pxref{Quitting,,,emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
+(@pxref{Quitting}).
address@hidden ifnottex
+By contrast, @address@hidden @emph{is} detected as soon as you
+type it (as @kbd{C-g} is on other systems), so it can be used to stop
+a running command and for emergency escape
address@hidden
+(@pxref{Emergency Escape,,,emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
+(@pxref{Emergency Escape}).
address@hidden ifnottex
+
address@hidden Meta (under MS-DOS)
address@hidden Hyper (under MS-DOS)
address@hidden Super (under MS-DOS)
address@hidden dos-super-key
address@hidden dos-hyper-key
+  The PC keyboard maps use the left @key{ALT} key as the @key{META} key.
+You have two choices for emulating the @key{SUPER} and @key{HYPER} keys:
+choose either the right @key{CTRL} key or the right @key{ALT} key by
+setting the variables @code{dos-hyper-key} and @code{dos-super-key} to 1
+or 2 respectively.  If neither @code{dos-super-key} nor
address@hidden is 1, then by default the right @key{ALT} key is
+also mapped to the @key{META} key.  However, if the MS-DOS international
+keyboard support program @file{KEYB.COM} is installed, Emacs will
address@hidden map the right @key{ALT} to @key{META}, since it is used for
+accessing characters like @kbd{~} and @kbd{@@} on non-US keyboard
+layouts; in this case, you may only use the left @key{ALT} as @key{META}
+key.
+
address@hidden C-j @r{(MS-DOS)}
address@hidden dos-keypad-mode
+  The variable @code{dos-keypad-mode} is a flag variable that controls
+what key codes are returned by keys in the numeric keypad.  You can also
+define the keypad @key{ENTER} key to act like @kbd{C-j}, by putting the
+following line into your @file{_emacs} file:
+
address@hidden
+;; @r{Make the @key{ENTER} key from the numeric keypad act as @kbd{C-j}.}
+(define-key function-key-map [kp-enter] [?\C-j])
address@hidden smallexample
+
address@hidden MS-DOS Mouse
address@hidden Mouse Usage on MS-DOS
+
address@hidden mouse support under MS-DOS
+  Emacs on MS-DOS supports a mouse (on the default terminal only).
+The mouse commands work as documented, including those that use menus
+and the menu bar
address@hidden
+(@pxref{Menu Bar,,,emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
+(@pxref{Menu Bar}).
address@hidden ifnottex
+ Scroll bars don't work in MS-DOS Emacs.  PC mice usually have only
+two buttons; these act as @kbd{Mouse-1} and @kbd{Mouse-2}, but if you
+press both of them together, that has the effect of @kbd{Mouse-3}.  If
+the mouse does have 3 buttons, Emacs detects that at startup, and all
+the 3 buttons function normally, as on X.
+
+  Help strings for menu-bar and pop-up menus are displayed in the echo
+area when the mouse pointer moves across the menu items.  Highlighting
+of mouse-sensitive text
address@hidden
+(@pxref{Mouse References,,,emacs, the Emacs Manual})
address@hidden iftex
address@hidden
+(@pxref{Mouse References})
address@hidden ifnottex
+is also supported.
+
address@hidden mouse, set number of buttons
address@hidden msdos-set-mouse-buttons
+  Some versions of mouse drivers don't report the number of mouse
+buttons correctly.  For example, mice with a wheel report that they
+have 3 buttons, but only 2 of them are passed to Emacs; the clicks on
+the wheel, which serves as the middle button, are not passed.  In
+these cases, you can use the @kbd{M-x msdos-set-mouse-buttons} command
+to tell Emacs how many mouse buttons to expect.  You could make such a
+setting permanent by adding this fragment to your @file{_emacs} init
+file:
+
address@hidden
+;; @r{Treat the mouse like a 2-button mouse.}
+(msdos-set-mouse-buttons 2)
address@hidden example
+
address@hidden Windows clipboard support
+  Emacs built for MS-DOS supports clipboard operations when it runs on
+Windows.  Commands that put text on the kill ring, or yank text from
+the ring, check the Windows clipboard first, just as Emacs does on the
+X Window System
address@hidden
+(@pxref{Mouse Commands,,,emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
+(@pxref{Mouse Commands}).
address@hidden ifnottex
+Only the primary selection and the cut buffer are supported by MS-DOS
+Emacs on Windows; the secondary selection always appears as empty.
+
+  Due to the way clipboard access is implemented by Windows, the
+length of text you can put into the clipboard is limited by the amount
+of free DOS memory that is available to Emacs.  Usually, up to 620KB of
+text can be put into the clipboard, but this limit depends on the system
+configuration and is lower if you run Emacs as a subprocess of
+another program.  If the killed text does not fit, Emacs outputs a
+message saying so, and does not put the text into the clipboard.
+
+  Null characters also cannot be put into the Windows clipboard.  If the
+killed text includes null characters, Emacs does not put such text into
+the clipboard, and displays in the echo area a message to that effect.
+
address@hidden dos-display-scancodes
+  The variable @code{dos-display-scancodes}, when address@hidden,
+directs Emacs to display the @acronym{ASCII} value and the keyboard scan code 
of
+each keystroke; this feature serves as a complement to the
address@hidden command, for debugging.
+
address@hidden MS-DOS Display
address@hidden Display on MS-DOS
address@hidden faces under MS-DOS
address@hidden fonts, emulating under MS-DOS
+
+  Display on MS-DOS cannot use font variants, like bold or italic, but
+it does support multiple faces, each of which can specify a foreground
+and a background color.  Therefore, you can get the full functionality
+of Emacs packages that use fonts (such as @code{font-lock}, Enriched
+Text mode, and others) by defining the relevant faces to use different
+colors.  Use the @code{list-colors-display} command
address@hidden
+(@pxref{Frame Parameters,,,emacs, the Emacs Manual})
address@hidden iftex
address@hidden
+(@pxref{Frame Parameters})
address@hidden ifnottex
+and the @code{list-faces-display} command
address@hidden
+(@pxref{Faces,,,emacs, the Emacs Manual})
address@hidden iftex
address@hidden
+(@pxref{Faces})
address@hidden ifnottex
+to see what colors and faces are available and what they look like.
+
+  @xref{MS-DOS and MULE}, later in this chapter, for information on
+how Emacs displays glyphs and characters that aren't supported by the
+native font built into the DOS display.
+
address@hidden cursor shape on MS-DOS
+  When Emacs starts, it changes the cursor shape to a solid box.  This
+is for compatibility with other systems, where the box cursor is the
+default in Emacs.  This default shape can be changed to a bar by
+specifying the @code{cursor-type} parameter in the variable
address@hidden
address@hidden
+(@pxref{Creating Frames,,,emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
+(@pxref{Creating Frames}).
address@hidden ifnottex
+The MS-DOS terminal doesn't support a vertical-bar cursor,
+so the bar cursor is horizontal, and the @address@hidden parameter,
+if specified by the frame parameters, actually determines its height.
+For this reason, the @code{bar} and @code{hbar} cursor types produce
+the same effect on MS-DOS.  As an extension, the bar cursor
+specification can include the starting scan line of the cursor as well
+as its width, like this:
+
address@hidden
+ '(cursor-type bar @var{width} . @var{start})
address@hidden example
+
address@hidden
+In addition, if the @var{width} parameter is negative, the cursor bar
+begins at the top of the character cell.
+
address@hidden frames on MS-DOS
+  The MS-DOS terminal can only display a single frame at a time.  The
+Emacs frame facilities work on MS-DOS much as they do on text-only
+terminals
address@hidden
+(@pxref{Frames,,,emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
+(@pxref{Frames}).
address@hidden ifnottex
+When you run Emacs from a DOS window on MS-Windows, you can make the
+visible frame smaller than the full screen, but Emacs still cannot
+display more than a single frame at a time.
+
address@hidden frame size under MS-DOS
address@hidden mode4350
address@hidden mode25
+  The @code{mode4350} command switches the display to 43 or 50
+lines, depending on your hardware; the @code{mode25} command switches
+to the default 80x25 screen size.
+
+  By default, Emacs only knows how to set screen sizes of 80 columns by
+25, 28, 35, 40, 43 or 50 rows.  However, if your video adapter has
+special video modes that will switch the display to other sizes, you can
+have Emacs support those too.  When you ask Emacs to switch the frame to
address@hidden rows by @var{m} columns dimensions, it checks if there is a
+variable called @address@hidden@var{m}}, and if so,
+uses its value (which must be an integer) as the video mode to switch
+to.  (Emacs switches to that video mode by calling the BIOS @code{Set
+Video Mode} function with the value of
address@hidden@address@hidden in the @code{AL} register.)
+For example, suppose your adapter will switch to 66x80 dimensions when
+put into video mode 85.  Then you can make Emacs support this screen
+size by putting the following into your @file{_emacs} file:
+
address@hidden
+(setq screen-dimensions-66x80 85)
address@hidden example
+
+  Since Emacs on MS-DOS can only set the frame size to specific
+supported dimensions, it cannot honor every possible frame resizing
+request.  When an unsupported size is requested, Emacs chooses the next
+larger supported size beyond the specified size.  For example, if you
+ask for 36x80 frame, you will get 40x80 instead.
+
+  The variables @address@hidden@var{m}} are used only
+when they exactly match the specified size; the search for the next
+larger supported size ignores them.  In the above example, even if your
+VGA supports 38x80 dimensions and you define a variable
address@hidden with a suitable value, you will still get
+40x80 screen when you ask for a 36x80 frame.  If you want to get the
+38x80 size in this case, you can do it by setting the variable named
address@hidden with the same video mode value as
address@hidden
+
+  Changing frame dimensions on MS-DOS has the effect of changing all the
+other frames to the new dimensions.
+
address@hidden MS-DOS File Names
address@hidden File Names on MS-DOS
address@hidden file names under MS-DOS
address@hidden init file, default name under MS-DOS
+
+  On MS-DOS, file names are case-insensitive and limited to eight
+characters, plus optionally a period and three more characters.  Emacs
+knows enough about these limitations to handle file names that were
+meant for other operating systems.  For instance, leading dots
address@hidden  in file names are invalid in MS-DOS, so Emacs transparently
+converts them to underscores @samp{_}; thus your default init file
address@hidden
+(@pxref{Init File,,,emacs, the Emacs Manual})
address@hidden iftex
address@hidden
+(@pxref{Init File})
address@hidden ifnottex
+is called @file{_emacs} on MS-DOS.  Excess characters before or after
+the period are generally ignored by MS-DOS itself; thus, if you visit
+the file @file{LongFileName.EvenLongerExtension}, you will silently
+get @file{longfile.eve}, but Emacs will still display the long file
+name on the mode line.  Other than that, it's up to you to specify
+file names which are valid under MS-DOS; the transparent conversion as
+described above only works on file names built into Emacs.
+
address@hidden backup file names on MS-DOS
+  The above restrictions on the file names on MS-DOS make it almost
+impossible to construct the name of a backup file
address@hidden
+(@pxref{Backup Names,,,emacs, the Emacs Manual})
address@hidden iftex
address@hidden
+(@pxref{Backup Names})
address@hidden ifnottex
+without losing some of the original file name characters.  For
+example, the name of a backup file for @file{docs.txt} is
address@hidden even if single backup is used.
+
address@hidden file names under Windows 95/NT
address@hidden long file names in DOS box under Windows 95/NT
+  If you run Emacs as a DOS application under Windows 9X, Windows ME, or
+Windows 2000/XP, you can turn on support for long file names.  If you do
+that, Emacs doesn't truncate file names or convert them to lower case;
+instead, it uses the file names that you specify, verbatim.  To enable
+long file name support, set the environment variable @env{LFN} to
address@hidden before starting Emacs.  Unfortunately, Windows NT doesn't allow
+DOS programs to access long file names, so Emacs built for MS-DOS will
+only see their short 8+3 aliases.
+
address@hidden @env{HOME} directory under MS-DOS
+  MS-DOS has no notion of home directory, so Emacs on MS-DOS pretends
+that the directory where it is installed is the value of the @env{HOME}
+environment variable.  That is, if your Emacs binary,
address@hidden, is in the directory @file{c:/utils/emacs/bin}, then
+Emacs acts as if @env{HOME} were set to @samp{c:/utils/emacs}.  In
+particular, that is where Emacs looks for the init file @file{_emacs}.
+With this in mind, you can use @samp{~} in file names as an alias for
+the home directory, as you would on GNU or Unix.  You can also set
address@hidden variable in the environment before starting Emacs; its
+value will then override the above default behavior.
+
+  Emacs on MS-DOS handles the directory name @file{/dev} specially,
+because of a feature in the emulator libraries of DJGPP that pretends
+I/O devices have names in that directory.  We recommend that you avoid
+using an actual directory named @file{/dev} on any disk.
+
address@hidden MS-DOS Printing
address@hidden Printing and MS-DOS
+
+  Printing commands, such as @code{lpr-buffer}
address@hidden
+(@pxref{Printing,,,emacs, the Emacs Manual}) and @code{ps-print-buffer}
+(@pxref{PostScript,,,emacs, the Emacs Manual})
address@hidden iftex
address@hidden
+(@pxref{Printing}) and @code{ps-print-buffer} (@pxref{PostScript})
address@hidden ifnottex
+can work on MS-DOS by sending the output to one of the printer ports,
+if a Posix-style @code{lpr} program is unavailable.  The same Emacs
+variables control printing on all systems, but in some cases they have
+different default values on MS-DOS.
+
address@hidden
address@hidden Printing,,,emacs, the Emacs Manual},
address@hidden iftex
address@hidden
address@hidden Printing},
address@hidden ifnottex
+for details about setting up printing to a networked printer.
+
+  Some printers expect DOS codepage encoding of address@hidden text, even
+though they are connected to a Windows machine which uses a different
+encoding for the same locale.  For example, in the Latin-1 locale, DOS
+uses codepage 850 whereas Windows uses codepage 1252.  @xref{MS-DOS and
+MULE}.  When you print to such printers from Windows, you can use the
address@hidden RET c} (@code{universal-coding-system-argument}) command before
address@hidden lpr-buffer}; Emacs will then convert the text to the DOS
+codepage that you specify.  For example, @kbd{C-x RET c cp850-dos RET
+M-x lpr-region RET} will print the region while converting it to the
+codepage 850 encoding.  You may need to create the @address@hidden
+coding system with @kbd{M-x codepage-setup}.
+
address@hidden dos-printer
address@hidden dos-ps-printer
+  For backwards compatibility, the value of @code{dos-printer}
+(@code{dos-ps-printer}), if it has a value, overrides the value of
address@hidden (@code{ps-printer-name}), on MS-DOS.
+
+
address@hidden MS-DOS and MULE
address@hidden International Support on MS-DOS
address@hidden international support @r{(MS-DOS)}
+
+  Emacs on MS-DOS supports the same international character sets as it
+does on GNU, Unix and other platforms
address@hidden
+(@pxref{International,,,emacs, the Emacs Manual}),
address@hidden iftex
address@hidden
+(@pxref{International}),
address@hidden ifnottex
+including coding systems for converting between the different
+character sets.  However, due to incompatibilities between
+MS-DOS/MS-Windows and other systems, there are several DOS-specific
+aspects of this support that you should be aware of.  This section
+describes these aspects.
+
+  The description below is largely specific to the MS-DOS port of
+Emacs, especially where it talks about practical implications for
+Emacs users.  For other operating systems, see the @file{code-pages.el}
+package, which implements support for MS-DOS- and MS-Windows-specific
+encodings for all platforms other than MS-DOS.
+
address@hidden @kbd
address@hidden M-x dos-codepage-setup
+Set up Emacs display and coding systems as appropriate for the current
+DOS codepage.
+
address@hidden M-x codepage-setup
+Create a coding system for a certain DOS codepage.
address@hidden table
+
address@hidden codepage, MS-DOS
address@hidden DOS codepages
+  MS-DOS is designed to support one character set of 256 characters at
+any given time, but gives you a variety of character sets to choose
+from.  The alternative character sets are known as @dfn{DOS codepages}.
+Each codepage includes all 128 @acronym{ASCII} characters, but the other 128
+characters (codes 128 through 255) vary from one codepage to another.
+Each DOS codepage is identified by a 3-digit number, such as 850, 862,
+etc.
+
+  In contrast to X, which lets you use several fonts at the same time,
+MS-DOS normally doesn't allow use of several codepages in a single
+session.  MS-DOS was designed to load a single codepage at system
+startup, and require you to reboot in order to change
address@hidden, one particular codepage is burnt into the
+display memory, while other codepages can be installed by modifying
+system configuration files, such as @file{CONFIG.SYS}, and rebooting.
+While there is third-party software that allows changing the codepage
+without rebooting, we describe here how a stock MS-DOS system
+behaves.}.  Much the same limitation applies when you run DOS
+executables on other systems such as MS-Windows.
+
address@hidden unibyte operation @r{(MS-DOS)}
+  If you invoke Emacs on MS-DOS with the @samp{--unibyte} option
address@hidden
+(@pxref{Initial Options,,,emacs, the Emacs Manual}),
address@hidden iftex
address@hidden
+(@pxref{Initial Options}),
address@hidden ifnottex
+Emacs does not perform any conversion of address@hidden
+characters.  Instead, it reads and writes any address@hidden
+characters verbatim, and sends their 8-bit codes to the display
+verbatim.  Thus, unibyte Emacs on MS-DOS supports the current
+codepage, whatever it may be, but cannot even represent any other
+characters.
+
address@hidden dos-codepage
+  For multibyte operation on MS-DOS, Emacs needs to know which
+characters the chosen DOS codepage can display.  So it queries the
+system shortly after startup to get the chosen codepage number, and
+stores the number in the variable @code{dos-codepage}.  Some systems
+return the default value 437 for the current codepage, even though the
+actual codepage is different.  (This typically happens when you use the
+codepage built into the display hardware.)  You can specify a different
+codepage for Emacs to use by setting the variable @code{dos-codepage} in
+your init file.
+
address@hidden language environment, automatic selection on @r{MS-DOS}
+  Multibyte Emacs supports only certain DOS codepages: those which can
+display Far-Eastern scripts, like the Japanese codepage 932, and those
+that encode a single ISO 8859 character set.
+
+  The Far-Eastern codepages can directly display one of the MULE
+character sets for these countries, so Emacs simply sets up to use the
+appropriate terminal coding system that is supported by the codepage.
+The special features described in the rest of this section mostly
+pertain to codepages that encode ISO 8859 character sets.
+
+  For the codepages which correspond to one of the ISO character sets,
+Emacs knows the character set name based on the codepage number.  Emacs
+automatically creates a coding system to support reading and writing
+files that use the current codepage, and uses this coding system by
+default.  The name of this coding system is @address@hidden, where
address@hidden is the codepage address@hidden standard Emacs coding
+systems for ISO 8859 are not quite right for the purpose, because
+typically the DOS codepage does not match the standard ISO character
+codes.  For example, the letter @samp{@,{c}} (@samp{c} with cedilla) has
+code 231 in the standard Latin-1 character set, but the corresponding
+DOS codepage 850 uses code 135 for this glyph.}
+
address@hidden mode line @r{(MS-DOS)}
+  All the @address@hidden coding systems use the letter @samp{D}
+(for ``DOS'') as their mode-line mnemonic.  Since both the terminal
+coding system and the default coding system for file I/O are set to
+the proper @address@hidden coding system at startup, it is normal
+for the mode line on MS-DOS to begin with @samp{-DD\-}.
address@hidden
address@hidden Line,,,emacs, the Emacs Manual}.
address@hidden iftex
address@hidden
address@hidden Line}.
address@hidden ifnottex
+Far-Eastern DOS terminals do not use the @address@hidden coding
+systems, and thus their initial mode line looks like the Emacs
+default.
+
+  Since the codepage number also indicates which script you are using,
+Emacs automatically runs @code{set-language-environment} to select the
+language environment for that script
address@hidden
+(@pxref{Language Environments,,,emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
+(@pxref{Language Environments}).
address@hidden ifnottex
+
+  If a buffer contains a character belonging to some other ISO 8859
+character set, not the one that the chosen DOS codepage supports, Emacs
+displays it using a sequence of @acronym{ASCII} characters.  For example, if 
the
+current codepage doesn't have a glyph for the letter @address@hidden (small
address@hidden with a grave accent), it is displayed as @address@hidden@}}, 
where
+the braces serve as a visual indication that this is a single character.
+(This may look awkward for some non-Latin characters, such as those from
+Greek or Hebrew alphabets, but it is still readable by a person who
+knows the language.)  Even though the character may occupy several
+columns on the screen, it is really still just a single character, and
+all Emacs commands treat it as one.
+
address@hidden IBM graphics characters (MS-DOS)
address@hidden box-drawing characters (MS-DOS)
address@hidden line-drawing characters (MS-DOS)
+  Not all characters in DOS codepages correspond to ISO 8859
+characters---some are used for other purposes, such as box-drawing
+characters and other graphics.  Emacs maps these characters to two
+special character sets called @code{eight-bit-control} and
address@hidden, and displays them as their IBM glyphs.
+However, you should be aware that other systems might display these
+characters differently, so you should avoid them in text that might be
+copied to a different operating system, or even to another DOS machine
+that uses a different codepage.
+
address@hidden dos-unsupported-character-glyph
+  Emacs supports many other characters sets aside from ISO 8859, but it
+cannot display them on MS-DOS.  So if one of these multibyte characters
+appears in a buffer, Emacs on MS-DOS displays them as specified by the
address@hidden variable; by default, this glyph
+is an empty triangle.  Use the @kbd{C-u C-x =} command to display the
+actual code and character set of such characters.
address@hidden
address@hidden Info,,,emacs, the Emacs Manual}.
address@hidden iftex
address@hidden
address@hidden Info}.
address@hidden ifnottex
+
address@hidden codepage-setup
+  By default, Emacs defines a coding system to support the current
+codepage.  To define a coding system for some other codepage (e.g., to
+visit a file written on a DOS machine in another country), use the
address@hidden codepage-setup} command.  It prompts for the 3-digit code of
+the codepage, with completion, then creates the coding system for the
+specified codepage.  You can then use the new coding system to read and
+write files, but you must specify it explicitly for the file command
+when you want to use it
address@hidden
+(@pxref{Text Coding,,,emacs, the Emacs Manual}).
address@hidden iftex
address@hidden
+(@pxref{Text Coding}).
address@hidden ifnottex
+
+  These coding systems are also useful for visiting a file encoded using
+a DOS codepage, using Emacs running on some other operating system.
+
address@hidden MS-Windows codepages
+  MS-Windows provides its own codepages, which are different from the
+DOS codepages for the same locale.  For example, DOS codepage 850
+supports the same character set as Windows codepage 1252; DOS codepage
+855 supports the same character set as Windows codepage 1251, etc.
+The MS-Windows version of Emacs uses the current codepage for display
+when invoked with the @samp{-nw} option.  Support for codepages in the
+Windows port of Emacs is part of the @file{code-pages.el} package.
+
address@hidden MS-DOS Processes
address@hidden Subprocesses on MS-DOS
+
address@hidden compilation under MS-DOS
address@hidden inferior processes under MS-DOS
address@hidden compile @r{(MS-DOS)}
address@hidden grep @r{(MS-DOS)}
+  Because MS-DOS is a single-process ``operating system,''
+asynchronous subprocesses are not available.  In particular, Shell
+mode and its variants do not work.  Most Emacs features that use
+asynchronous subprocesses also don't work on MS-DOS, including
+Shell mode and GUD.  When in doubt, try and see; commands that
+don't work output an error message saying that asynchronous processes
+aren't supported.
+
+  Compilation under Emacs with @kbd{M-x compile}, searching files with
address@hidden grep} and displaying differences between files with @kbd{M-x
+diff} do work, by running the inferior processes synchronously.  This
+means you cannot do any more editing until the inferior process
+finishes.
+
+  Spell checking also works, by means of special support for synchronous
+invocation of the @code{ispell} program.  This is slower than the
+asynchronous invocation on other platforms
+
+  Instead of the Shell mode, which doesn't work on MS-DOS, you can use
+the @kbd{M-x eshell} command.  This invokes the Eshell package that
+implements a Posix-like shell entirely in Emacs Lisp.
+
+  By contrast, Emacs compiled as a native Windows application
address@hidden support asynchronous subprocesses.
address@hidden
address@hidden Processes,,,emacs, the Emacs Manual}.
address@hidden iftex
address@hidden
address@hidden Processes}.
address@hidden ifnottex
+
address@hidden printing under MS-DOS
+  Printing commands, such as @code{lpr-buffer}
address@hidden
+(@pxref{Printing,,,emacs, the Emacs Manual}) and
address@hidden (@pxref{PostScript,,,emacs, the Emacs Manual}),
+work in MS-DOS by sending the output to one of the printer ports.
address@hidden Printing,,,emacs, the Emacs Manual}.
address@hidden iftex
address@hidden
+(@pxref{Printing}) and @code{ps-print-buffer} (@pxref{PostScript}),
+work in MS-DOS by sending the output to one of the printer ports.
address@hidden Printing}.
address@hidden ifnottex
+
+  When you run a subprocess synchronously on MS-DOS, make sure the
+program terminates and does not try to read keyboard input.  If the
+program does not terminate on its own, you will be unable to terminate
+it, because MS-DOS provides no general way to terminate a process.
+Pressing @kbd{C-c} or @address@hidden might sometimes help in these
+cases.
+
+  Accessing files on other machines is not supported on MS-DOS.  Other
+network-oriented commands such as sending mail, Web browsing, remote
+login, etc., don't work either, unless network access is built into
+MS-DOS with some network redirector.
+
address@hidden directory listing on MS-DOS
address@hidden dired-listing-switches @r{(MS-DOS)}
+  Dired on MS-DOS uses the @code{ls-lisp} package where other
+platforms use the system @code{ls} command.  Therefore, Dired on
+MS-DOS supports only some of the possible options you can mention in
+the @code{dired-listing-switches} variable.  The options that work are
address@hidden, @samp{-a}, @samp{-c}, @samp{-i}, @samp{-r}, @samp{-S},
address@hidden, @samp{-t}, and @samp{-u}.
+
address@hidden
+   arch-tag: 868d50ff-07f8-4a13-a807-dab6f1cdb431
address@hidden ignore