Differences

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--- doc:appunti:hardware:eeepc_debian [2010/11/06 18:52] – niccolo
+++ doc:appunti:hardware:eeepc_debian [2010/11/07 11:26] – niccolo
@@ Line 359: / Line 359: @@
 EndSection
 </file>
+Per vedere le ''XkbOptions'' attive usare il comando:
+<code>
+setxkbmap -print
+xkb_keymap {
+        xkb_keycodes  { include "evdev+aliases(qwerty)" };
+        xkb_types     { include "complete"      };
+        xkb_compat    { include "complete"      };
+        xkb_symbols   { include
+            "pc+us+it:2+gr:3+inet(evdev)+level3(ralt_switch)+compose(menu)+eurosign(e)" };
+        xkb_geometry  { include "pc(pc105)"     };
+};
+</code>
+Per impostare le opzioni //una tantum// da riga di comando:
+<code>
+setxkbmap -option lv3:ralt_switch,compose:menu,eurosign:e
+</code>
 ===== xfce =====
@@ Line 391: / Line 411: @@
 </code>
-===== Disk performances and TRIM command =====
+===== Disk performances =====
 Asus EeePC 900, disk performances measured with **''hdparm -t''**
@@ Line 398: / Line 418: @@
 ^ /dev/sdb  | 25.46 MB/sec  | Second SSD, 16 Gb  |
 ^ /dev/sdc  | 14.51 MB/sec  | MiniSD card, 4 Gb  |
+==== TRIM command ====
 Solid State Disks should support the [[wp>TRIM]] command, this is a command used by the operating system to inform a SSD that a particular sector is no longer used and can be internally wiped.
@@ Line 414: / Line 436: @@
 /dev/sda: DSM/TRIM command not supported, aborting.
 </code>
+==== Journal data writeback ====
+To gain a little in disk performances, you can enable writeback for journal data. Here it is an example for the ''/dev/sdb1'' partition, formatted as ext3 and mounted under ''/home''.
+<code>
+tune2fs -o journal_data_writeback /dev/sdb1
+mount -o remount,data=writeback /dev/sdb1
+</code>
+To enable this option on bootstrap, you have to change **''/etc/fstab''**:
+<file>
+/dev/sda1  /home  ext3  defaults,noatime,data=writeback  0  1
+</file>
+For the root filesystem, it is required also to pass the option to the kernel, using a GRUB parameter. With Debian Squeeze the option is added into **''/etc/default/grub''**:
+<file>
+GRUB_CMDLINE_LINUX_DEFAULT="rootflags=data=writeback quiet"
+GRUB_CMDLINE_LINUX="rootflags=data=writeback"
+</file>
+Run **''update-grub''** to install that option into **''/boot/grub/grub.cfg''**.
 ===== WiFi interface =====
-The WiFi interface is supported by the new **ath5k** kernel module. Once loaded the **wlan0** interface is available.
+The WiFi interface is supported by the new **ath5k** kernel module. Once loaded, the **wlan0** interface is available.
-The new **''iw(8)''** command can be used to manipulate the device configuration. Here it is an example how to reconfigure the interface from scratch:
+The new **''iw(8)''** command can be used to manipulate the device configuration, its purpose is similar to the ''wlanconfig'' command, used with the old ''ath_pci'' kernel module.
+Here it is an example on how to deconfigure/reconfigure the interface from scratch:
 <code>
@@ Line 425: / Line 473: @@
 iw phy phy1 interface add wlan0 type managed
 </code>
+To use the WiFi interface with **''kismet''**, you need this in the **''/etc/kismet/kismet.conf''** configuration file:
+<file>
+source=ath5k,wlan0,atheros
+</file>
+After exiting ''kismet'', the ''wlan0'' interface must be reconfigured as explained above, and ''knetworkmanager'' should be restarted.