Volatile Yard 挥洒自如 Write anything I want to write...

(Part 1 is here if you haven't read it.)

Checked Again

A few hours ago, I connected my 'suspicious' Seagate 500GB harddisk to a motherboard of another computer. I fired up Palimpsest and checked the harddisk again. Oops, I got the same Last self-test FAILED (Read) error again. I repeated the test for a few more times and still got the same error.

I thought I couldn't do much with the harddisk already, so I started to shred [en.wikipedia.org] it. Why shred it? There were no sex videos on my harddisk, but these days you won't know how those weird people will make use of whatever irrelevant data you have in whatever ways beyond your imagination. So I just gave shred a few hours to do her job.

After shred-ing, I checked the harddisk again. I ran a self-test and re-ran both the short and conveyance self-tests for a few more times. Again and again, I got this:

Computer Hanged

My Linux box hanged yesterday! When a Linux box hangs, you normally blame (1) a memory-leaked program, (2) an I/O-hungry program, or (3) a hardware failure. Checked my Conky monitor, no program was swallowing my memory or I/O bandwidth. Hardware problem? I checked my /var/log/messages, and something really went wrong (I've highlighted those abnormal events):

  Mar 10 15:53:11 peace-desktop kernel: [ 2434.881018] ata3: hard resetting link
  Mar 10 15:53:18 peace-desktop kernel: [ 2442.392316] ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
  Mar 10 15:53:23 peace-desktop kernel: [ 2447.400079] ata3.00: qc timeout (cmd 0xec)
  Mar 10 15:53:23 peace-desktop kernel: [ 2447.400092] ata3.00: failed to IDENTIFY (I/O error, err_mask=0x4)
  Mar 10 15:53:23 peace-desktop kernel: [ 2447.400110] ata3: hard resetting link
  Mar 10 15:53:24 peace-desktop kernel: [ 2447.940060] ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
  Mar 10 15:53:24 peace-desktop kernel: [ 2447.943275] ata3.00: configured for UDMA/33
  Mar 10 15:53:24 peace-desktop kernel: [ 2447.943311] ata3: EH complete

Was it really a harddisk problem? Turned out that it's not that simple yet!

Last Updated (07-Mar-09): Added the monitoring of CPU fan speed.

I have recently discovered Conky, a very nice light-weight system monitor. A screenshot along with the current configuration file are attached below.

Sometimes, especially if you have just installed Windows operating system alongside with your Ubuntu, your precious Grub boot loader will be wiped out from the MBR (Master Boot Record) from your hard disk. How do you restore it?

The steps here have been tested with Ubuntu 9.10.

1. Boot into the Ubuntu Live CD or USB stick.
2. Open a terminal with 'Accessories' -> 'Terminal'.
3. Find out the partition that correspond to your root /. If you have a separate partition for /boot, find it out too. The command sudo fdisk -l may help. Here we assume that the partitions are /dev/sda1 and /dev/sda2 (if any) respectively.
4. Now mount your root partition with sudo mount /dev/sda1 /mnt. If you have a separate partition for /boot, mount it too with sudo mount /dev/sda2 /mnt.
5. Restore Grub with sudo grub-install --root-directory=/mnt /dev/sda. (Assume that you want to install Grub to the MBR of /dev/sda.)

Reboot your computer and it should work fine now.

I have just installed Ubuntu 9.10 Karmic Koala, and have spent some time to customize my Xfce panel. I have used GIMP to create a snapshot of my panel, split it into two (since the panel is too wide, with 1440 pixels), and attach them here.

I configured to use only one panel, with a height of 34 pixels at the bottom of the screen.

The Left Part

The left part of the panel consists of the items below (from left to right):

1. Xfce Menu. Only shows the icon to save space.
2. Places. For fast access.
3. Launcher for Firefox. I use Firefox often.
4. Launcher for Chromium. I use Google Chromium often too. Add the repository with a simple sudo add-apt-repository ppa:chromium-daily
5. Launcher for Xfce Terminal. A must-have for hardcore GNU/Linux hacker!
6. Separator. A Line.
7. Task List. I configure it to 'Never group tasks'.
8. Separator. A Line.

The Right Part

This part is much more dynamic and interesting.

1. Weather Update. I can access the weather details and forecast in a few clicks. Handy information for me before hanging clothes outside!
2. Dictionary. I have also added the web service with URL http://dictionary.sina.com.hk/p/word/{word} for English <-> Chinese translation.
3. Notes. The 'physical' sticky notes I used did not stick well on the edge of my monitor. I resort to this 'soft' sticky notes for the moment. Bad thing is that it has to occupy some display area and not all notes are visible anytime.
4. Governor Plugin. I use the 'ondemand' governor most of the time to save power and reduce the heat generated. Will use 'performance' governor sometimes when I'm desperate. :p
5. CPUFreq. Shows the current CPU frequency, in GHz.
6. System Load Monitor. Shows monitors for CPU, memory, swap, and uptime respectively.
7. Free Space Checkter for /tmp. I have modified /etc/fstab to mount /tmp as tmpfs with this line: tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0. The capacity of tmpfs in my box, mounted with 4GB RAM, is 2GB. It's sufficient but it's better to monitor its space usage, as I often use /tmp to hold temporary files when compiling software, hold temporary ISO images during disc burning, etc.
8. Network Monitor. The maximums for incoming and outgoing are set to be 200 kBytes/s and 50 kBytes/s respectively.
9. Sensor plugin. sensors-detect found that I need to use the it87 module, but the module will not load successfully under Karmic Koala due to 'ACPI: I/O resource it87 [0x295-0x296] conflicts with ACPI region ECRE [0x290-0x2af]' as found in dmesg. To workaround with the problem, edit /etc/default/grub by assigning GRUB_CMDLINE_LINUX="acpi_enforce_resources=lax", execute sudo update-grub2, and reboot the box. I configured it to show M/B Temp, CPU Temp, and the temperatures of two hard disks.
10. Workspace Switcher. I use 6 workspaces, shown in 3 rows here.
11. Notification Area. The volume control and IBus input method framework are always accessible here.
12. Orage Clock. Line 1: %R, with font Sans 10. Line 2: %d-%b, with font Sans Bold 10.
13. Action Buttons. To lock the screen with just one click.

Your comments or suggestions are welcomed.

IMPORTANT NOTE!!!

For updated and latest instructions for Ubuntu 9.10 onwards, go to this page.
This page keeps only the OBSOLETE instructions for setting up this printer up to Ubuntu 9.04 in case some people still need it.

Update (25-Apr-09): Updated for Ubuntu 9.04 Jaunty Jackalope and Samsung Unified Driver version 3.xx
Update (08-Nov-08): Updated for Ubuntu 8.10 Intrepid Ibex
Update (30-Apr-08): Improved the workaround with hal-cups-utils
Update (28-Apr-08): Updated for Ubuntu 8.04 Hardy Heron
Update (23-Oct-07): Updated for Ubuntu 7.10 Gutsy Gibbon

I started to use my Fuji Xerox WorkCentre PE220 since Ubuntu 7.10, and I needed to do many tricks to install the driver properly. But since Ubuntu 9.04 and Samsung Unified Driver version 3.xx, the installation is so easy and it works out-of-box!

Note that the installation steps involved differ for different Ubuntu and driver versions. I make this guide more 'practical' by only showing the steps for the latest Ubuntu (9.04 Jaunty Jackalope) and printer driver (version 3.xx).

1. Download the Unified Linux Printer Driver from Samsung

Some Xerox printers are Samsung OEM. This Xerox WorkCentre PE220 looks like a clone of Samsung SCX-4521F [www.samsung.com] (Note: This link changed very often! Navigate from the main page if the link does not work.) except that it has a slightly different button layout on the control panel. Download the driver. The latest driver I use is UnifiedLinuxDriver.tar.gz (Version 3.00.37) as of this writing.

Configuring internet connection sharing in GNU/Linux normally involves modifying several configuration files and issuing several commands. You need to at least:

• Give Linux kernel the permission to forward network packets;
• Set up DHCP service;
• Set up firewall and route the network packets properly;
• Set up DNS forwarder.

This is definitely not user-friendly for beginners or for those who just want to set up a simple network.

Luckily, since version 0.7 of NetworkManager [projects.gnome.org], shipped with Ubuntu 8.10 and later, includes a very simple GUI for you set up a simple NAT network.

Suppose that you want to set up the following network: