Enable higher screen resolution in VirtualBox (for Ubuntu)

This might work on other systems too, I tried it on Ubuntu 14.04.1.

In VirtualBox the screen for Ubuntu was very small and it was difficult to see what’s on the screen. To fix this issue, you need to install the following packages on the guest (VM) box:

sudo apt-get install virtualbox-guest-dkms virtualbox-guest-x11

If you get this error:

The following packages have unmet dependencies. virtualbox-guest-x11 : Depends: xorg-video-abi-15

You will need to remove this package (note: I am not sure what all this removes, it was a lot – use caution):

sudo apt-get remove libcheese-gtk23

Then install these

sudo apt-get install xserver-xorg-core-lts-trusty

And

sudo apt-get install xserver-xorg-core

Then try to install the virtualbox packages, as the first step:

sudo apt-get install virtualbox-guest-dkms virtualbox-guest-x11

Once they install properly, restart the VM and the screen should be normal size. You might need to increase the Display memory in VB before starting the VM.

Fix White Screen of Death in WordPress (3.3.1?)

I haven’t updated WordPress for a while and I was getting the what is know as White Screen Of Death. Basically once I login on the admin panel, all the screens are white and I cannot click or do anything.

In the source of the pages, there is an error message like:

Fatal error: Access to undeclared static property: WP_Screen::$this in wp-admin/includes/screen.php on line 706

To fix this, you will need to access the files on the server, and modify the following file in your favorite text editor:

your-site/wp-admin/includes/screen.php

Go to line 706 and modify the line from:

<?php echo self::$this->_help_sidebar; ?>

to

<?php echo $this->_help_sidebar; ?>

In summary, remove the ‘self::‘ part.

Save it and re-login/refresh your WordPress admin panel.

Add or modify the IP address for Wireless Printer Brother MFC-J6920DW in Linux

If you set up the printer Brother MFC-J6920DW on the network and with their brsaneconfig4 utility in Linux, the value is hard-coded in a file, so if the router is reset and you lose the IP address associated with the printer, some of the functionalists (mainly scanner) will not work.

To fix this, you should edit the following file:

vi /etc/opt/brother/scanner/brscan4//brsanenetdevice4.cfg

Or if you prefer gedit

gedit /etc/opt/brother/scanner/brscan4//brsanenetdevice4.cfg

Modify the IP address at the end of the file to the new IP address that the printer has. To find the new IP address, check the settings on the printer or your router.

The line should look something like this:

DEVICE=MFC-J6920DW , "MFC-J6920DW" , 0x4f9:0x2f5 , IP-ADDRESS=192.168.1.4

If this file is empty, most likely you haven’t set up the scanner with the Brother’s tool (you can download it freely from their website), and if you like to set it up, run the following:

brsaneconfig4 -a name=MFC-J6920DW model=MFC-J6920DW ip=192.168.1.4

That should be it.

Enable Delete button in Gnome

By default the Delete button does not move files to trash, you need to use Ctrl+Delete which is major annoyance. This is after 3.2 Gnome I believe and still the same up to 3.10. They say it is a feature but I don’t see it as such.

To fix this, you will need to modify the accels of Gnome, with few simple steps:

Run the following in the terminal as your user:

gsettings set org.gnome.desktop.interface can-change-accels true

Now you are able to give items different buttons.

Select a file that you might want to delete (create New Folder for example) and after you have selected it, go to the Edit menu (right-click doesn’t work) and position your mouse over the Move To Trash field. Once the field is in focus, press the Delete button twice. The button combination on the right should be changed from Ctrl+Delete to Delete only.

That is all, now it is enabled. You should disable changing of accels now because you might accidentally do it for other things:

gsettings set org.gnome.desktop.interface can-change-accels false

 

This was tested on Gnome 3.4.2 on Debian Wheezy.

Setup plugins directory in Linux (debian) for Firefox

I had issues with Firefox not finding the plugins for flash. I had to setup the following environment variable for it to find it:

Check if it is already set:

echo $MOZ_PLUGIN_PATH

If it is not, set it:

export MOZ_PLUGIN_PATH=/home/user/.mozilla/plugins

Any path will work, I just used the .mozilla directory to keep things clean.

You should restart Firefox to see the plugins.

 

This was tested on Debian Wheezy.

Recover data from a damaged hard disk drive

I would like to begin this presentation by first stating that I am not an electronic technician. Nor do I have any more than a very basic understanding of hard disk drive technology. I have a basic understanding of computer technology and of electricity. You do not have to be uber skilled to do what I did.

I successfully retrieved lost data from a dead hard disk drive for a few cents more than $100. I had been quoted $590 and up by professional data recovery firms to do what I did. The following presentation is a brief summary of what I did and how it worked. I cannot guarantee it will work for everyone. I can advise you to be very careful if you try to do any of the things that I did because it is possible that you can so badly corrupt your drive that any data on it might be lost forever.

Before you begin, do what you are doing right now. That is, go on the Internet and read, read, read and then read some more.

BACKGROUND

The disk drive was accidentally exposed to water. The water caused the printed circuit board to dysfunction. My friend, the owner of the drive replaced it and gave it to me to try to recover his data if I could. The arrangements were I could keep the drive in exchange for any data I might be able to recover from it.

My preliminary assessment was that the data was most probably intact. The platters had never been opened or exposed to air in anyway. The printed circuit board was the only part of the drive that had been damaged as a result of the accident. I wrongly assumed that I could simply, “hot swap,” the circuit board that had stopped working for another one from some other drive.

The disk drive details:

Brand: Hitachi
HDD: 5K250-250
Model: HTS542525K9SA00
RPM: 5400
Power: 5v 700mA DC
Capacity: 250GB
Type: SATA
P/N: 0A54876
MLC: DA2010

Complete 2.5″ HDD, PCB has been unscrewed

I have a source locally that is involved in dismantling and recycling computers of all kinds. He advised me that from time to time he gets small SATA drives and he has to drill a hole in them to insure that no data can ever be retrieved from any of them. However he told me that would not stop him from giving me the printed circuit boards if I wanted them.

But when I told him about my project to recover data he told me that he was uncertain why but he was pretty sure that I could not simply hot swap boards between drives with any hope of retrieving data or resurrecting a dead drive. That opinion was further substantiated by another friend who provided me with the following Internet link to the HDD Guru Forum.

ACTUAL REPAIR PROCEDURE

The article on HDD Guru is also a basic primer that explains why it is not possible to simply hot swap one printed circuit board for another when trying to recover data. The key to understanding that is a thing called the NVRAM or the Non-Volatile Random Access Memory chip. While it would appear that two identical drives have identical circuit boards attached to them that is not totally true. It is true that the boards themselves do operate identically and removing one and replacing it with the other is a piece of cake involving a few tiny screws and some careful physical work.

PCB only, NVRAM removed and placed on top of another chip with scotch tape to avoid losing it

But the individual boards are unique in as much as all of the information about the specific hard disk drive is stored within the NVRAM chip. So while the boards will physically move from one drive to the next they will not operate unless the NVRAM chip is moved as well.

The above article includes two photos of the kind of printed circuit board I worked with including a highlighted diagram of where to find the NVRAM chip.

The first problem I addressed was moving that chip. From a casual glance at the dead drive that I had I knew that there was no way that I could ever dream of doing that type of board level electronic work. But here where I live I am familiar with a TV repair shop that has done circuit board work for me in the past when they removed and reinstalled IC circuit chips in an old Sony TV I owned.

I consulted the technician in that shop and he said that moving the NVRAM, which is basically an 8-legged EPROM or an Erasable Programmable Read Only Memory device, is an easy procedure. The NVRAM performs so that once it has been programmed the information contained in it remains non-volatile. So no matter if the power is turned on or off the data remains safe. The technician I spoke with in the TV shop advised me that he has to move those kinds of chips all of the time. It seems that in modern electronics often the new replacement part is unusable unless the original EPROM chip is removed from the old part and then soldered onto the new part. He estimated the labor cost for moving my NVRAM at $25.

The next problem I encountered was finding a donor drive. As I began this discussion I will remind you that I don’t have detailed hard disk drive knowledge. So I was kind of shooting in the dark. On the HDD GURU forums there are various discussions authored by learned individuals who speak of the various characteristics that must be matched between circuit boards. But given the gamble I was taking I determined to set my own standards as I attempted to match a donor drive to my dead drive.

I first determined that the physical description of the two drives had to match exactly (Hitachi, HDD:5K250-250, Model:HTS542525K9SA00). Next I decided that the part numbers for the printed circuit boards should also match because that would insure that the two boards would physically interchange with each other (p/n 0A54876). Finally, I decided that the MLC should also match (DA2010). I know that experienced technicians might suggest that there are other boards which would also interchange but I determined to play it safe and apply my own personal standards in selecting my donor drive.

I also note that there are other characteristics between my donor drive and my dead drive that did not match. There are a variety of numbers on both the hard disk drive enclosure as well as the two PCBs that do not match. I don’t know what those numbers mean but I assumed that if the basic information like the size of the drive, the numbers of heads, the speed, the voltage, the number of cylinders etc. all matched then the two boards would probably interchange. I also noted that if the model numbers, pin numbers, and MLC numbers matched those other characteristics should also match.

Finally, I needed a USB, SATA, hard disk drive enclosure in order to have a way to attach the repaired disk drive to my computer. There are countless numbers of them on the market and I bought mine for less than $10 from Amazon. Enough said.

When I was finally able to locate a donor drive, my cost was $55 plus freight. When it arrived the very first thing I did was record all of the characteristics about the two drives and the two PCBs so that they would not become confused during the exchange process. I then careful removed the individual PCBs using the standard static precautions employed in handling any electronic circuitry. Basically you should not touch the PCB except by the edges but there are many places on the internet that can help you understand the precautions in dealing with electrostatic discharge and how it can ruin a printed circuit board.

 

Bare HDD, no PCB

After I delivered the two printed circuit boards to the TV shop technician, I waited about a week to get them back. I advised the technician to retain the donor NVRAM as I supposed that if my experiment failed I could at least put it back and have one functional hard disk drive. But my concerns were unfounded. He was able to successfully exchange the NVRAM that matched my dead drive with the one that was on the donor drive PCB. When I swapped out my dead PCB with the donor PCB that now had my NVRAM chip soldered onto it, everything worked perfectly.

RECAP

Just to recap exactly what I did, I had a dysfunctional hard disk drive printed circuit board which had on it the NVRAM which had all of my disk drive’s data in it. I also had a printed circuit board which was functional but which had on it an NVRAM that contained data about that other hard disk drive. I had the technician exchange the two NVRAM chips so that the functional printed circuit board now had on it my data’s NVRAM chip.

For me the work involved finding a functional drive that matched, and then carefully removing the two circuit boards and safely packing them into electrostatic bags to deliver to the TV technician.

I was able to recover all of the lost data off of my friend’s hard disk drive. The drive functions perfectly and I am actually considering installing it in my laptop as it has a greater capacity than the drive I am currently using.

The final cost for the whole operation total just a bit more than $100. The expenses were as follows:

USB SATA hard disk drive enclosure ........ $  5.58
Used Hitachi donor drive .................. $ 55.00
Shipping for above ........................ $  6.00
TV technician labor fees .................. $ 35.00

Total charges ............................. $101.58

This was a guest post by TJD.

Recover MySQL root password on Linux and Windows

It happens that sometimes (after 2 days :) ) you forget the password for your root user on MySQL, well there are few steps to perform to recover it.

This was performed on version:

$ mysql -V
mysql  Ver 14.14 Distrib 5.1.61, for debian-linux-gnu (x86_64) using readline 6.2

The following steps need to be performed as root user, so either login with it or use sudo.

Step 1:Stop the MySQL service

$ sudo /etc/init.d/mysql stop

Step 2: Start the MySQL server without password

$ sudo mysqld_safe --skip-grant-tables &

Step 3: Connect to the MySQL server using the MySQL client

$ sudo mysql -u root

Step 4: Change the password for the root user

mysql> use mysql;
Database changed
mysql> update user set password=PASSWORD("YOUR_NEW_PASS") where user = 'root';
Query OK, 3 rows affected (0.01 sec)
Rows matched: 3  Changed: 3  Warnings: 0
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Bye

Step 5: Stop the MySQL server again

$ sudo /etc/init.d/mysql stop

Step 6: Start the MySQL server (normally) and test the new password

$ sudo /etc/init.d/mysql start
$ sudo mysql -u root -p

 

This should also work on Windows as well, you will just need to use different commands for start/stop of the MySQL deamon.

 

 

Surveillance system with Motion

There is a time when you are leaving your home empty and you don’t have an expensive security and alarm system. You need to be protected and be aware if there are any changes or visits that you do not approve of while you are gone. There is an easy way to achieve just that with Motion. What you need is:

  1. Linux OS (ex. Ubuntu)
  2. Motion (free)
  3. Webcam
  4. Internet (optional)
  5. Hosting (optional)
  6. Smartphone with data plan (optional)

After you have your computer ready, webcam installed and working, go and download the Motion project or use Ubuntu’s apt to get it (check to get the latest version):

sudo apt-get install motion

Run the program (Motion) with root privileges, like sudo motion, however please note that you should probably run it with sleep or cron, otherwise it will activate immediately and most probably detect you while you are exiting the room.

Now you are all set for the basic surveillance with just a webcam which will record when there is a movement in front of the camera, however there are some more advanced options which could help a lot.

Email you when there is movement detected

For this you will need to install sendmail and mutt, assuming you are on Ubuntu

sudo apt-get install sendmail mutt

The basic settings for sendmail are enough for most users, but if you are an advanced user feel free to modify it as you desire.

Open the file /etc/motion/motion.conf in your favorite text editor (ex. vim), then locate the text on_even_start value and change the value part with:

echo "This is the body of the message" | mutt -s "Motion has been detected" your@mail.com

If there is a ; (semi-colon) on the beginning of the row, remove it, also if there is any empty space before the on_event_start.

Sending images to a webserver

It would be good to have the images taken from the motion to a webserver so that you can check from a remote location what is there on the images and report to the police if needed.
Open the /etc/motion/motion.conf file again in a text editor and locate the text on_picture_save value and change the value part with:

scp %f user@yourdomain.com:/path/for/images/

If there is a ; (semi-colon) on the beginning of the row, remove it, also if there is any empty space before the on_picture_save.

Enable login without password on your webserver

You need to create a ssh key on your machine with the following

sudo ssh-keygen -t dsa

Upload the key to your webserver:

sudo ssh-copy-id -i /root/.ssh/id_dsa.pub user@yourdomain.com

Tips and tricks: if you have a LED light on your camera, put a plastic electrician tape (isolation tape) on it so that the camera is not noticeable. Also, make sure you have some light in the room, unless the camera has a feature for night vision.

Making rounded corners in GIMP

I bugged myself a little to create an image in GIMP which will have rounded corners. I tried with selection tools and everything else I could think of to no avail. Then I browsed trough the Filters selections and I found the script Round Corners. The image I created was initially like this (you can also import a picture):

Looks kinda dull and boring, so now we will make it with round edges and make it more interesting :)

Click on the Filters -> Decor -> Round Corners… and a new window with settings will be shown.

NOTE: if the filter Round Corners is grayed-out and you cannot select it, it means that the image has Alpha channel, so you need to remove that. Go to Layer -> Transparency -> Remove Alpha Channel

The window with the settings should look like this

The default settings might not work for everybody, so you can test it how it transforms and what you need.

The options are pretty much self explanatory, so for example if you do not want any shadows just set the Shadow X/Y offset to 0, Work on copy will create a new file and will not modify the original, Add Background will put the new image on a background etc.

The default settings will generate an image like this

You can see the rounded edges, the shadow, the blur on the shadow and the background (white). Now the image looks much slicker and more modern.

Let me know if you have questions about this in the comments below.

Change default search engine in Firefox (in address bar)

The default search engine in Firefox is Google. There is a way to change it to whichever search engine you wish. In this post I will talk for transferring the default search from Google to DuckDuckGo. I am experimenting with DDG now and seeing if it will suit my needs better than Google.

Instant Search

For the instant search () you can easily add new search engines or select one on the go, there is even a GUI which will help you add new ones, remove and edit them

When you are on a website that offers search services, you will see a new entry “Add <site>” in the instant search list of engines, click it and it will be added automatically. So visit https://www.duckduckgo.com/ now to add it if you wish.

Default Search in Address Bar

The default search is the address bar (), instead of typing a URL, you type a search query and hit enter. The search query is then passed to your default search engine and the results are displayed on their website.

There is a way to modify the default search engine in Firefox, start by typing this in the address bar:

about:config

agree to the warning and in the search field enter the following:

browser.search.defaultenginename

It should show one row and the Value field should be Google. Double click on it, and enter the value of your desired default search engine (in this case DuckDuckGo).

Click OK and you are good to go.

Note: The search engine that you want to make as your default must be in the Instant Search list.

This is good for productivity if you are using multiple search engines, you can set them on each and search faster without distractions.

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