Aqeel Zafar’s Randomness

File system is a system to store and access the files (and directories) on any computer. Usually users don’t have to worry about which file system they are using, operating systems take care of it all. Though knowing their strength and weaknesses can sometimes help one to choose better option depending on the scenario.

There are many file systems present, suitable for different needs and can be categorized in many different categories, though we aren’t going to discuss them all here (if you are interested, you can check the list of all file system). In most Linux distributions, there is option to choose from two to five different file systems, which can be classified in two general categories:

• Journaled (or journaling) File System
• Non-journaled File System

Journaling File System:

Journaling file systems makes a log (or journal) of all the changes made before they are written to disk. This is helpful when system crash or power failure may cause loss of some data, while the changes are still being written to disk. In such case, system compares the disk state with journal, and update the disk where required, resulting in data recovery.

Every file has two parts, data and meta data. Data (or user data) is everything present in the file, that is, in case of text file it will be all the text present in file, for music file, it will be the music etc. whereas, meta data is data about data, like when was file last accessed, modified or created. Title of the song and artist information for music file and author information stored by some office programs is also meta-data.

This brings us to a sub-category of journaled file system.

• Meta-data Journaling

As the name implies, meta data journaling file systems only log the meta data of the file and not the user data. It provides better performance then complete journaling file system, but doesn’t provide full data recovery options.

Non-journaled File System:

Non-journaled file system are those which doesn’t provide journaling. Which means in case of system crash or power failure, there are chances of data getting corrupt. It also means data is written just once (as it doesn’t have to written to the journal) there are fewer read/write operations on disk compared to journaled file system, which makes it preferable to use on flash drives and other solid-state drives, which can increase their life span.

That’s all for now, in next post I will provide comparison of different file systems for linux.

Due to some personal problems, I had to swap my notebook (Sony VAIO) with my brother’s (Acer Aspire 5720, also known as TravelMate 5720), for a month. So, like any honorable linux geek, I didn’t waste any time and installed linux - Ubuntu 8.04 - on it.

Hardware:

• VGA: Intel X3100
• Audio: Intel 82801H HDA (ICH8 Family), builtin microphone
• Modem: Conexant
• Ethernet: Broadcom NetLink BCM5787M Gigabit Ethernet
• Wireless: Intel PRO/Wireless 3945abg Network Connection
• Special Keys: FN keys, volume control, hotkeys (wireless, bluetooth & two editable keys), euro sign, dollar sign
• Misc: Card Reader, Bluetooth, InfraRed

What Works:

I really love it when everything just works, and with Aspire 5720, everything really does, well atleast all the important stuff anyway. VGA, audio, ethernet, FN keys, volume control, wireless, bluetooth and power saving options (hibernate and suspend) works out of the box.

What Doesn’t Work:

• Modem: Unfortunately, soft-modems are still a weak point for linux, though, fewer and fewer people use dialup connections now, so, it’s not much of a problem. If you really want a driver, you can get it from linuxant.com, for a suitable price ofcourse.
• Programmable Hot keys: These hot keys don’t work out of the box, and I couldn’t find any way to make them work in my quick google search.

Couldn’t Try Completely:

• Wireless: Intel PRO/Wireless 3945abg is fully supported in linux, and according to many reports works out of the box in ubuntu but I wasn’t able to check that because my wireless router is out of order.
• InfraRed: I don’t have any infrared device, so, didn’t check it either.

Conclusion:

I don’t have vast experience with notebooks, I have only tried a few, but out of these all Acer Aspire 5720 offers most hardware compatibility with linux. So, if you are looking for a nice laptop to use with linux, I would definately vote for this machine.

I recently did a fresh install of Kubuntu 8.04 (hardy) on my Sony Vaio (VGN-NR220E), this is a list of notebook hardware that does or doesn’t work with linux. It is mostly based on my experience with kubuntu 8.04, but it should be pretty much same with other distributions, using latest kernel.

First of all, a little about hardware:

• VGA: Intel X3100 - chipset: Intel Mobile GL960
• Audio: Intel 82801H HDA (ICH8 Family)
• Modem: Conexant HDAUDIO SoftV92 Data Fax Modem with SmartCP
• Ethernet: Marvell Technologies 88E8039
• Wireless: Atheros AR5007EG (most probably)
• Misc: Builtin Card Readers (SD/MMC/Express Card/Sony Memory Stick)

Works:

• Audio: Works out of the box.
• VGA: Works out of the box
• Ethernet: Works out of the box, it uses “sky2″ module, so, if it doesn’t work in your distro, make sure it is loaded.
• Card Readers: Works out of the box, Only tried with SD card, but I assume others should work too.
• Wireless: Atheros AR5007EG drivers are available from madwifi, but they are quite new, and currently they are not available in any distro that I know of. You can manually install the new/patched madwifi drivers.
  Step-by-step instructions are provided at ubuntu forums. Ubuntu users can follow it step-by-step, others can look at it to get the general idea.
• LCD Brightness: You will need xbacklight (a command-line only program) to change the LCD brightness. You can change brightness using the following command:
  xbacklight -set X
  where X is any value from 0 - 100, if that doesn’t work, then run
  xrandr --output LVDS --set BACKLIGHT_CONTROL native
  and then try again. Hopefully this will work now. For future, you can add the xrandr line in your ~/.profile file (that is .profile file in your home directory), so, that you won’t have to run it yourself after every login.

Doesn’t Work:

• Modem: Drivers for conexant are available from linuxant.com for “a modest price”. I don’t really need modem so, I never tried hard looking for open source drivers but the quick google search didn’t return any satisfactory results.
• Keys: FN keys, S1 and AV Mode.

I am still trying to get the keys to work, if you have any idea, please let me know.

Once again, we are observing DST (Daylight Saving Time) in Pakistan; tonight at midnight, all clocks were moved one hour ahead - causing an hour early power load-shedding :(.

If you are living in Pakistan and haven’t changed your computer clock yet, you can update the zone info and have your computer automatically change it’s time (both tonight and at the end of DST).

For more information click on your operating system: Microsoft Windows or Linux (unix, bsd, solaris).

Update: Corrected the link for linux, which reflects the DST changes in Pakistan, that is, DST will continue till October 31st, instead of August 31st.

Today, while browsing the LinuxMint forums, I found a link to a nice article Linux is Not Windows.

It is aimed at Windows users coming to Linux, and would help them set their expectations. If you have never understood why people like Linux so much, or had trouble explaining why you like it, then go ahead and read it.