Update docs for change to UTF-8 by default, and emphasise UTF-8 more generally.

[u/mdw/putty] / doc / config.but

diff --git a/doc/config.but b/doc/config.but
index 9842758..467ea28 100644 (file)
--- a/doc/config.but
+++ b/doc/config.but
@@ -1254,12 +1254,16 @@ mechanism for PuTTY and the server to communicate this information,
 so it must usually be manually configured.
 
 There are a lot of character sets to choose from. The \q{Remote
-character set} option lets you select one. By default PuTTY will
-attempt to choose a character set that is right for your \i{locale} as
-reported by Windows; if it gets it wrong, you can select a different
-one using this control.
+character set} option lets you select one.
 
-A few notable character sets are:
+By default PuTTY will use the \i{UTF-8} encoding of \i{Unicode}, which
+can represent pretty much any character; data coming from the server
+is interpreted as UTF-8, and keystrokes are sent UTF-8 encoded. This
+is what most modern distributions of Linux will expect by default.
+However, if this is wrong for your server, you can select a different
+character set using this control.
+
+A few other notable character sets are:
 
 \b The \i{ISO-8859} series are all standard character sets that include
 various accented characters appropriate for different sets of
@@ -1273,12 +1277,6 @@ Euro symbol.
 \b If you want the old IBM PC character set with block graphics and
 line-drawing characters, you can select \q{\i{CP437}}.
 
-\b PuTTY also supports \i{Unicode} mode, in which the data coming from
-the server is interpreted as being in the \i{UTF-8} encoding of Unicode,
-and keystrokes are sent UTF-8 encoded. If you select \q{UTF-8} as a
-character set you can use this mode. Not all server-side applications
-will support it.
-
 If you need support for a numeric \i{code page} which is not listed in
 the drop-down list, such as code page 866, then you can try entering
 its name manually (\c{\i{CP866}} for example) in the list box. If the
@@ -3208,6 +3206,29 @@ send an over-sized packet.  If this bug is enabled when talking to a
 correct server, the session will work correctly, but download
 performance will be less than it could be.
 
+\S{config-ssh-bug-winadj} \q{Chokes on PuTTY's SSH-2 \cq{winadj} requests}
+
+\cfg{winhelp-topic}{ssh.bugs.winadj}
+
+PuTTY sometimes sends a special request to SSH servers in the middle
+of channel data, with the name \cw{winadj@putty.projects.tartarus.org}
+(see \k{sshnames-channel}). The purpose of this request is to measure
+the round-trip time to the server, which PuTTY uses to tune its flow
+control. The server does not actually have to \e{understand} the
+message; it is expected to send back a \cw{SSH_MSG_CHANNEL_FAILURE}
+message indicating that it didn't understand it. (All PuTTY needs for
+its timing calculations is \e{some} kind of response.)
+
+It has been known for some SSH servers to get confused by this message
+in one way or another \dash because it has a long name, or because
+they can't cope with unrecognised request names even to the extent of
+sending back the correct failure response, or because they handle it
+sensibly but fill up the server's log file with pointless spam, or
+whatever. PuTTY therefore supports this bug-compatibility flag: if it
+believes the server has this bug, it will never send its
+\cq{winadj@putty.projects.tartarus.org} request, and will make do
+without its timing data.
+
 \H{config-serial} The Serial panel
 
 The \i{Serial} panel allows you to configure options that only apply