Xorg

Il demone Xorg si occupa dell'intefaccia gracia di Linux. Xorg nasce come costola di XFree86, per poi diventare un programma a se stante, totalmente Open Source, al contrario di Xfree86 che aveva deciso di includere in parte driver proprietario.

L'interfaccia grafica in linux si avvia, di solito, quando il pc vene messo in init 5, cioe' nella configurazione di runlevel 5. Slackware e' l'unica che la tiene nel runlevel 4.

Se il vostro computer non vi mostra nessuna interfaccia grafica lanciate il comando

 $ startx

e si avviera' il vostro desktop manager preferito.

Se invete volete vede la schermata grafica di richiesta del login con la scelta del Desktop manager lanciate come root:

 # init 5

(oppure init 4 se usate Slackeware)

Chiaramente se volete evitarvi tutta questa procedura ogni volta modificate il file /etc/inittab cosi':

 # These are the default runlevels:
 #   0 = halt
 #   1 = single user mode
 #   2 = unused (but configured the same as runlevel 3)
 #   3 = multiuser mode 
 #   4 = unused (but configured the same as runlevel 3)
 #   5 = X11 with KDM/GDM/XDM (session managers)
 #   6 = reboot
 # Default runlevel. (Do not set to 0 or 6)
 id:5:initdefault:

in queto caso ogni riga cominciante per # e' ignorata del programma, e' solo un commento per capirci qualcosa.

Desktop manager

Ecco una lista dei desktop manager piu' diffusi, potete installarli tutti e poi scegliere di giorno in giorno quello che piu' vi aggrada:

Alcuni sono vere e prorpie suite desktop complete di moltissimi programmi in piu' (KDE e GNOME), altre servono solo a gestire le finestre in modo personale, ed altre ancora servono a risparmiare le risorse del PC. Per una guida piu' approfondita leggete: http://xwinman.org/

Il server X

Xorg, chiamato anche server X, nasce per gestire piu' schede grafiche, utenti, tastiere e monitor alla volta. Se avete l'hardware potete farci tutto!

Il file piu' importante di configurazione, ed anche l'unico, e' /etc/X11/xorg.conf.

Quello che segue e' il file di configurazione per un pc con scheda Radeon 9250 e monitor Philips da 17":

 # File generated by xorgconfig.
 # **********************************************************************
 # Refer to the xorg.conf(5x) man page for details about the format of 
 # this file.
 # **********************************************************************
 # **********************************************************************
 # Module section -- this  section  is used to specify
 # which dynamically loadable modules to load.
 # **********************************************************************
 #
 Section "Module"
 # This loads the DBE extension module.
    Load        "dbe"  	# Double buffer extension
 # This loads the miscellaneous extensions module, and disables
 # initialisation of the XFree86-DGA extension within that module.
    SubSection  "extmod"
      Option    "omit xfree86-dga"   # don't initialise the DGA extension
    EndSubSection
 # This loads the font modules
    Load        "type1"
 #    Load        "speedo"
    Load        "freetype"
 #    Load        "xtt"
 # This loads the GLX module
    Load       "glx"
 # This loads the DRI module
    Load       "dri"
 EndSection
 # **********************************************************************
 # Files section.  This allows default font and rgb paths to be set
 # **********************************************************************
 Section "Files"
 # The location of the RGB database.  Note, this is the name of the
 # file minus the extension (like ".txt" or ".db").  There is normally
 # no need to change the default.
    RgbPath	"/usr/X11R6/lib/X11/rgb"
 # Multiple FontPath entries are allowed (which are concatenated together),
 # as well as specifying multiple comma-separated entries in one FontPath
 # command (or a combination of both methods)
    FontPath   "/usr/X11R6/lib/X11/fonts/misc/"
    FontPath   "/usr/X11R6/lib/X11/fonts/TTF/"
    FontPath   "/usr/X11R6/lib/X11/fonts/Type1/"
    FontPath   "/usr/X11R6/lib/X11/fonts/CID/"
    FontPath   "/usr/X11R6/lib/X11/fonts/75dpi/"
    FontPath   "/usr/X11R6/lib/X11/fonts/100dpi/"
    FontPath   "/usr/X11R6/lib/X11/fonts/local/"
    FontPath   "/usr/X11R6/lib/X11/fonts/Speedo/"
    FontPath   "/usr/X11R6/lib/X11/fonts/cyrillic/"
 # The module search path.  The default path is shown here.
 #    ModulePath "/usr/X11R6/lib/modules"
 EndSection
 # **********************************************************************
 # Server flags section.
 # **********************************************************************
 Section "ServerFlags"
 EndSection
 # **********************************************************************
 # Input devices
 # **********************************************************************
 # **********************************************************************
 # Core keyboard's InputDevice section
 # **********************************************************************
 Section "InputDevice"
    Identifier	"Keyboard1"
    Driver	"kbd"
    Option "AutoRepeat" "500 30"
    Option "XkbRules"	"xorg"
    Option "XkbModel"	"pc104"
    Option "XkbLayout"	"it"
 EndSection
 # **********************************************************************
 # Core Pointer's InputDevice section
 # **********************************************************************
 Section "InputDevice"
 # Identifier and driver
    Identifier	"Mouse1"
    Driver	"mouse"
    Option "Protocol"    "IMPS/2"	# IntelliMouse PS/2
    Option "Device"      "/dev/mouse"
    Option "ZAxisMapping"   "4 5 6 7"
 EndSection
 # **********************************************************************
 # Monitor section
 # **********************************************************************
 # Any number of monitor sections may be present
 Section "Monitor"
    Identifier  "Philips170S4"
    HorizSync   31.5 - 64.3
    VertRefresh 50-90
 EndSection
 # **********************************************************************
 # Graphics device section
 # **********************************************************************
 # Standard VGA Device:
 Section "Device"
    Identifier	"Standard VGA"
    VendorName	"Unknown"
    BoardName	"Unknown"
     Driver     "vga"
 EndSection
 # Device configured by xorgconfig:
 Section "Device"
    Identifier  "Radeon2500"
    Driver      "radeon"
    VideoRam    262144
 EndSection
 # **********************************************************************
 # Screen sections
 # **********************************************************************
 Section "Screen"
    Identifier  "Screen 1"
    Device      "Radeon2500"
    Monitor     "Philips170S4"
    DefaultDepth 24
    Subsection "Display"
        Depth       8
        Modes       "1280x1024" "1024x768" "800x600" "640x480"
        ViewPort    0 0
    EndSubsection
    Subsection "Display"
        Depth       16
        Modes       "1280x1024" "1024x768" "800x600" "640x480"
        ViewPort    0 0
    EndSubsection
    Subsection "Display"
        Depth       24
        Modes       "1280x1024" "1024x768" "800x600" "640x480"
        ViewPort    0 0
    EndSubsection
 EndSection
 # **********************************************************************
 # ServerLayout sections.
 # **********************************************************************
 Section "ServerLayout"
    Identifier  "Simple Layout"
    Screen "Screen 1"
    InputDevice "Mouse1" "CorePointer"
    InputDevice "Keyboard1" "CoreKeyboard"
 EndSection

Il modo piu' semplice per configurare il file xorg.conf e' usare il programma:

 # xorgconfig