+.B XAUTH and XDM
+For xscreensaver to work when launched by
+.BR xdm (1),
+programs running on the local machine as user \fI"nobody"\fP must be
+able to connect to the X server. This means that if you want to run
+xscreensaver on the console while nobody is logged in, you may need
+to disable cookie-based access control (and allow all users who can log
+in to the local machine to connect to the display.)
+
+You should be sure that this is an acceptable thing to do in your
+environment before doing it. See the ``\fIUsing XDM(1)\fP'' section,
+above, for more details.
+
+If anyone has suggestions on how xscreensaver could be made to work with
+.BR xdm (1)
+without first turning off \fI.Xauthority\fP-based access control, please
+let me know.
+.TP 8
+.B Passwords
+If you get an error message at startup like ``couldn't get password
+of \fIuser\fP'' then this probably means that you're on a system in which
+the
+.BR getpwent (3)
+library routine can only be effectively used by root. If this is the case,
+then \fIxscreensaver\fP must be installed as setuid to root in order for
+locking to work. Care has been taken to make this a safe thing to do.
+
+It also may mean that your system uses shadow passwords instead of the standard
+.BR getpwent (3)
+interface; in that case, you may need to change some options
+with \fIconfigure\fP and recompile.
+
+If you change your password after xscreensaver has been launched, it will
+continue using your old password to unlock the screen until xscreensaver
+is restarted. So, after you change your password, you'll have to do
+.EX
+xscreensaver-command -restart
+.EE
+to make \fIxscreensaver\fP notice.
+.TP 8
+.B PAM Passwords
+If your system uses PAM (Pluggable Authentication Modules), then in order
+for xscreensaver to use PAM properly, PAM must be told about xscreensaver.
+The xscreensaver installation process should update the PAM data (on Linux,
+by creating the file \fI/etc/pam.d/xscreensaver\fP for you, and on Solaris,
+by telling you what lines to add to the \fI/etc/pam.conf\fP file.)
+
+If the PAM configuration files do not know about xscreensaver, then
+you \fImight\fP be in a situation where xscreensaver will refuse to ever
+unlock the screen.
+
+This is a design flaw in PAM (there is no way for a client to tell the
+difference between PAM responding ``I have never heard of your module,''
+and responding, ``you typed the wrong password.'' As far as I can tell,
+there is no way for xscreensaver to automatically work around this, or
+detect the problem in advance, so if you have PAM, make sure it is
+configured correctly!
+.TP 8
+.B Colormap lossage: TWM
+The \fBinstallColormap\fP option doesn't work very well with the
+.BR twm (1)
+window manager and its descendants.
+
+There is a race condition between the screensaver and this window manager,
+which can result in the screensaver's colormap not getting installed
+properly, meaning the graphics hacks will appear in essentially random
+colors. (If the screen goes white instead of black, this is probably why.)
+
+The
+.BR mwm (1)
+and
+.BR olwm (1)
+window managers don't have this problem. The race condition exists
+because X (really, ICCCM) does not provide a way for an OverrideRedirect
+window to have its own colormap, short of grabbing the server (which is
+neither a good idea, nor really possible with the current design.) What
+happens is that, as soon as xscreensaver installs its colormap, \fBtwm\fP
+responds to the resultant \fBColormapNotify\fP event by re-instaling the
+default colormap. Apparently, \fBtwm\fP doesn't \fIalways\fP do this; it
+seems to do it regularly if the screensaver is activated from a menu item,
+but seems to not do it if the screensaver comes on of its own volition, or
+is activated from another console.
+.RS 8
+.TP 4
+.B Attention, window manager authors!
+You should only call
+.BR XInstallColormap (3)
+in response to user events. That is, it is appropriate to install a colormap
+in response to \fBFocusIn\fP, \fBFocusOut\fP, \fBEnterNotify\fP,
+and \fBLeaveNotify\fP events; but it is not appropriate to call it in
+response to \fBColormapNotify\fP events. If you install colormaps in
+response to \fIapplication\fP actions as well as in response to \fIuser\fP
+actions, then you create the situation where it is impossible for
+override-redirect applications (such as xscreensaver) to display their
+windows in the proper colors.
+.RE
+.TP 8
+.B Colormap lossage: XV, XAnim, XEarth
+Some programs don't operate properly on visuals other than the default one,
+or with colormaps other than the default one. See the discussion of the
+magic "default-n" visual name in the description of the \fBprograms\fP
+resource in the \fIConfiguration\fP section. When programs only work with
+the default colormap, you need to use a syntax like this:
+.EX
+ default-n: xv -root image-1.gif -quit \\n\\
+ default-n: xearth -nostars -wait 0 \\n\\
+.EE
+It would also work to turn off the \fBinstallColormap\fP option altogether,
+but that would deny extra colors to those programs that \fIcan\fP take
+advantage of them.
+.TP 8
+.B Machine Load