Saturday, April 5, 2014

Linux on Android using Complete Linux Installer: Hiccup and Fix!

The benefit of having a full linux distribution running on android device, such as Asus transformer Prime/Infinity, is up to who you are. For me as a developer, it's really a great platform for me to play around with new language, practice new skill and, experiment with new tools without mass up with my work notebook. For sys admin, it's quite a nice to have a full bowl linux to work on ... And I think Complete Linux Installer does a good job helping me to setup a linux distribution on android device.

Nothing perfect thou. There are a few hiccup ... a few annoying issues which may or may not have a fix for it. Keep in mind, the app allow to have a full linux running on android by chroot to a linux image, and connect to it with vnc or ssh. There will be some issues that there is no solution for it (or there is but I don't know :p)

Where is my eth0?

First hiccup after boot the system is this error message:
If connecting from a different mach ... android device use the address below:
eth0: error fetching interface information: Device not found

This is a simply the /root/init.sh expect the network interface to be "eth0". Unfortunately, that is not always true. To find out which interface you have, use "ifconfig". In my case, it is "wlan0".

To fix this, simply edit /root/init.sh script. Change "eth0" to "wlan0", in my case, and you will be done.




How much disk space I have?, "df" issue

This is quite annoy when simple command like "df" (diskfree) doesn't work at all. It's not report any thing. This is because the "df" command can not read file table which provide this information. Fortunately, there are easy solution for issue if all you want is to see how much disk space available.

By simply alias "df" to take which file system to report on, it's solve the problem. This time you edit /root/.bashrc script to add alias, as shown. This fix is only report disk space on "/" and "/sdcard", and it's not useful for other system tools which require to have device information.


Where is my external sdcard?

Like me, you probably have external microsd card install with the system. Is the "/sdcard" refer to this external sdcard? ... No it's not. It's the internal sdcard that come with the prime tablet.

Sorry to say, I don't know the answer to this question because the external sd card is mount on "/Removable/SD" which can not be access in the chroot system. There might be a way to allow access to /Removeable/SD from the chroot system, but I do not know now. If you know, please comment below. :)

Can I create normal account? What do I need to know?

Obviously, running the system as root is not a good idea. First thing, create a user using command
$ adduser new_user

What you need to do after that is adding the new_user to the following groups:
This will allow new_user to use network and also access both read and write to internal sdcard.

I also recommand to add new_user to group: sudo, users, ssh, and crontab if you plan to use it.

However, it's still booting directly to root! Obviously, you can just type

$ su -l new_user

And you will be right at home. However, it's an extra step to do after boot, which kinda annoying.
However, we can do this automatically but edit "/root/init.sh" once again.


The line "/bin/bash -i" is responsible for spwan a shell. We just has to replace that line with
"/bin/su -l new_user" and the system will boot directly to the new_user.

That's it! for today. See you next post ... which I will try to get more memory to the system by enabling swap image. :)

Using Linux on Android with Complete Linux Installater and debian testing-Large image.

If you have android tablet/phone and you wish to use full linux on it. You are in luck. I am running one on Asus Transformer Prime. You need to root the device thou. You can find out how to root your device from xda-developers.com.

Here is going to be my experience with "Complete Linux Installater" app, which you can find it on the app store for free. There is also a donation version too, $3.50.

What I like about Compete Linux Installer, is simplicity, good guide line and various of distribution of linux you can choose from. 

I start with debian testing (Jessie) small image. It's 2GB image file, and very easy to setup ... just follow the instruction and it will be done in second after long downloading and extracting of the image. There are a few hiccup that might consider annoying. I have fixed some of these "hiccup", and shared with you later.

Setup with debian testing LARGE image file:

Get back to my major issue. Since 2GB is too small after I try to get some serious work on it, I try debian testing LARGE image. This time it's not that simple any more. I find couple major issues with it.

Get The Right File:

First of all, the zip large image that I download by follow the app is damaged and can not be extract. I try different mirrors, always get the same result. So I googling and find this 

which you can directly download. Notice that there are couple of  images you can download from,
debian-testing, debian-8.LARGE.ext2 and debian-8.LARGE.ext4 ... The question is which one?

If you follow the app, it will download debian-8.LARGE.ext2 file, which about 500MB. This is the damage one. Since debian-8.LARGE.ext4 is about the same size, it's also damage one. The one that you have to download is

debian-testing.LARGE.ext4 (1.0GB) file.

Change the Script:

After a long wait for downloading and extracting, I expecting this image should work like a charm! ... Unfortunately, the bootscript is expecting the file system to be ext2, not ext4.  This can be solved pretty easily by changing the bootscript. The bootscript.sh is located here:
/data/data/com.zpwebsites.linuxonandroid/files/bootscript.sh
Use any editor you like, obviously :) ... and looking for the word "ext2", and the line is look some thing like this:
$bbox mount -t ext2 /dev/block/loop255 $mnt
$bbox is refer to "busybox" which the app provided. You can change to the one that you like, but I won't recommend. $mnt is the mount point, which is /data/local/mnt. Since the large image that I download is using ext4, I would have to change "ext2" to "ext4". The line become:
$bbox mount -t ext4 /dev/block/loop255 $mnt

At this point you should be about to boot up the debian testing LARGE image with ext4 file system, and enjoy 3.5gb space!

Next post, I am going to talk about hiccup that annoyance me and how I fix it.

Saturday, February 16, 2013

Mortgage Biweekly Option, the true.

Couple weeks ago, a little landed on my inbox. It's about "Biweekly Option" payment for mortgage.
Essentially say, if I setup a smaller biweekly payment (half of the monthly payment), I will reduce my loan term from 30 year to about 23.9 years. Therefore, I will save money on interest!

Ding! ... save money ... shoter team loan ... wow all good stuff! :D

So I called the number that they give me on the letter ...

Wait a minute, this is not my lender ... it's another financial instrution. What is going on here?
So I drop the call right away, and then start googling to find out how the "Biweekly Option" really work ... or worthwhile!

In short: No.
Long answer: it's depend, if you really want to pay off your mortgage early ... ya do it!  BUT do it yourself. You don't need the service offer in the letter.

Here is where I findout about this Biweekly option ... the true!

Just in case, if you wonder. I did call my lender, and they don't offer option to pay biweekly. They just say "No".

Sunday, October 28, 2012

Luminance HDR - A Linux HDR tool that I can actually use.

About a year ago, I came across Luminance HDR during a search
for linux HDR tools. I wasn't so impressed back then.

Now, after try Luminace HDR again, I was stunned by the result I get. 
And Yes, I find a Linux HDR tool that I can actually use! 

I took these pictures at Franciscan Monastery, a lost gem in DC.
You will find original photos at the end of the post.


Tuesday, October 23, 2012

Thursday, October 18, 2012

Canon 5D Mark II vs Mark III

First of all, I have to admit that I do not have neither 5D Mark II or Mark III. But I do own a Canon 5D thou. It was a little surprise for me when I heart about Mark III because I was still thinking about upgrade to Mark II.

Don't get me wrong, I love my 5D and I don't need the video features. That why I am still thinking about upgrade to Mark II (and never did). Should I upgrade to Mark III then? or Should I just save some money by upgrade to Mark II? ... Here what I found out:

You can find full spec and full review of Mark II here and Mark III here.

5D Mark II Mark III
Price  discontinue 1,799 3,459
year Aug 2005 Sept 2008 Mar 2012
Photography Features
LCD Size 2.5" 3.0" 3.2"
Max Resolution 4368x2912 5616x3744 5760x3940
(megapixels) 12.7 21.2 22.3
Processor Digic II Digic 4 Digic 5
ISO (Auto) 100-1600 in 1/3 stops 100-6400 in 1/3 stops 100-25600 in 1/3 stops
(manual) 50, 3200 50, 12800 and 51200 50, 51200 and 102400
Auto focus points 9 9 61
Viewfinder Coverage 96% 98% 100%
Continuous Drive 3 fps (60 JPEG, 17 RAW) 3.9 fps (78 JPEG, 13 RAW) 6 fps
Exposure Compensation ±2 EV (at 1/3 EV, 1/2 EV steps) ±2 EV (at 1/3 EV, 1/2 EV steps) ±5 EV (at 1/3 EV, 1/2 EV steps)
AE Bracketing ±2 (3 frames at 1/3 EV, 1/2 EV steps) ±2 (3 frames at 1/3 EV, 1/2 EV steps) ±3 (2, 3, 5, 7 frames at 1/3 EV, 1/2 EV steps)
Muli-exposure no no up to 9 exposures
HDR in cameras no no 5 options
Horizon level no no dual axis leveling
Weight 895g 850g 950g
Memory Card 1 CF 1 CF 1 CF and 1 SD
Video Features
1080 n/a yes yes
720 n/a no 60,50
640 n/a 30,25 30,25
Longest clip n/a 12 mins (approx) 30 mins
Microphone/ Headphone Jack n/a mono/no mono/yes
Audio level ctrl n/a yes (pre recording) yes (while recording)
Aperture control in video n/a no yes
Histogram in video n/a no yes
Chromatic Aberration fix n/a no yes
Time code support n/a no yes

Overall, Mark III is an improvement over Mark II in the photography featrues, little bit bigger censor, faster processor, wider range ISO, more auto focus points, two memory cards, etc. Mark III is greatly improve on HDR support, such as, HDR in cameras, AE Bracketing and Multi-exposure, and 6 fps would help to get better HDR pictures. For me, I wish to have 5 or 7 frame AE Bracketing for quite some time.

Beside HDR, I would say, other improved features are nice the have. It's won't convince me to pay almost double to get Mark III.

Obviously the different between Mark II and Mark III is in video features. I don't know much about it but I can see that Mark III is greatly improve over Mark II. If the video features are important to you, then you should consider Mark III.

On the other hand, if you are looking for your first canon full frame camera, spend some time looking at  Mark II, specially at this price. It is a great photography tools and it is must better than 5D. It come with video features that you can explore. If I am not mistake, Mark II is very successful in this area too.

For me, I already have 5D. I am still happy with it and I don't really need video features. So I probably wait and see how Mark IV is going to look like.