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SEARCH KEYWORD -- Samsung Galaxy Tab 3

  Samijyon : A tablet from North Korea

According to Sina Tech, North Korea Tech posted an article about Samijyon. Samijyon is a model of Android  tablet manufactured by North Korea. You can buy it with $200 in North Korea. Smajiyon's hardware configuration is as good as Samsung and Apple, but it doesn't allow WiFi connection and ordinary North Koreans cannot connect to Internet as well, users can only connect to domestic network of North Korea. On this tablet, there are no built-in Google apps such as Gmail and Google Play. But...

   Samijyon,North Korea,Tablet     2013-08-03 22:01:35

  A possible way to recover deleted files on Linux

Last week I was generating a MD5 sum for an virtual machine image on one OpenNebula server: # ls -l test.img -rw-r--r-- 1 root root 10486808576 Oct 12 02:21 test.img # md5sum test.img At the same time I was clearing the files on the server on another terminal and deleted the above image file mistakenly with : # rm test.img Since this image file is 10GB, it took some time to remove this file from the server, so I used the Ctrl+Z command to suspend the remove command. [1]+ Stopped ...

   Linux,File,Recovery     2013-11-26 07:03:37

  this in JavaScript in detail

this in JavaScript is always confusing, it is one of the most frequently seen traps in JavaScript. this is not a good design in JavaScript(You can refer some other design flaws of JavaScript here), since it's lazy binding feature, it can be a global object, the current object or.... Some people even avoid using this in JavaScript. Actually if you master how this works, then you will know how to stay away from these traps. Let's take a look at what this points to in below situations. 1. In global...

   JavaScript,this,bind     2013-05-09 18:35:12

  jQuery to check whether checkbox is checked

In Vanilla JavaScript, the correct way of checking whether a checkbox is checked is to get the property checked of the checkbox. Assuming there is an checkbox with id "checkbox1", below line will return true if the checkbox is checked while it will return false if the checkbox is unchecked: document.getElementById("checkbox1").checked In jQuery, there are a few ways to check this. The first one is to using the corresponding counterpart of the Vanilla JavaScript, it is to check the checked proper...

   jQuery,checked,checkbox,attr,prop     2015-07-25 08:49:54

  Why 0.1+0.2 != 0.3

In programming languages such as JavaScript, c/c++, Java and Matlab, you will find that you will get unexpected result when doing float point calculation. For example, when calculating 0.1 + 0.1, you will not get 0.3: > 0.1 + 0.2 == 0.3 false > 0.1 + 0.2 0.30000000000000004 Don't be surprised of this result, this is the end result of IEEE 754 standard, float point number cannot be accurately represented according to IEEE 754 because: No enough memory is allocated for representing the num...

   float point,comparison,JavaScript     2014-11-19 05:32:46

  Recover deleted file in Linux EXT3 file system

Environment : CentOS 5.3 x86_64, /dev/sdb1 is the data segment /data0. EXT3 file system. Problem : /data0/tcsql/cankao/phpcws-1.5.0/httpcws.cpp is deleted mistakenly and httpcws.cpp is not backed up. It will take much time to rewrite this program again. So we must recover it back. debugfs is feasible in EXT2 file system, but in EXT3 file system, it's not very useful. There is one open source software called ext3grep which can help us recover deleted file in EXT3 file system. The recovery steps a...

   Linux,EXT3,File recovery     2013-08-16 07:06:45

  Handy PHP functions should be in your toolkit

When developing projects, there are always some common work should be accomplished, for example, encrption/decryption, get IP. As a PHP developer, you should have a list of the handy functions in your toolkit so that you can pick up in every project you work on. Here is a summary of some handy PHP functions. 1. PHP encryption/decryption Encryption/decryption can be used when storing user confidential information such as passwords. Below function uses base64 and MD5 to accomplish encryption/decry...

   PHP,function,real IP,SQL injection     2014-12-06 08:46:08

  A Python assignment trap

Python has no assignment, it only has reference. Assume, we have following code snippet: >>> values = [0, 1, 2] >>> values[1] = values >>> values [0, [...], 2] Why the result is not [0, [0, 1, 2], 2], instead it goes into an infinite loop? To understand this, we need to understand some basics about Python. Python has no variables, it only has labels. When we run: values = [0, 1, 2] Python will first create a list object [0,1,2], then it labels it as values. If we later...

   Python,Assignment,Trap,Shallow copy     2013-07-19 22:08:36

  Build Hadoop environment in Linux

Hadoop standalone installation: 1. Install JDK Install JDK with below command: sudo apt-get install sun-java6-jdk Configure Java environment, open /etc/profile, add below contents: export JAVA_HOME = （Java installation directory） export CLASSPATH =".:$JAVA_HOME/lib:$CLASSPATH" export PATH = "$JAVA_HOME/:PATH" Verify installation of Java Type java --version, if it outputs Java version information, then Java is successfully installed. 2. Install SSH Install SSH with below command: sudo ...

   Hadoop.Linux,Configuration     2013-07-31 23:22:27

  Migrate from MySQL to MariaDB in Ubuntu

The biggest movement of escaping from MySQL in this century starts, openSUSE,Fedora and Arch have started to use MariaDB instead of MySQL as their default database. Many people also dislike the attitude of Oracle on MySQL, so it's reasonable to migrate from MySQL to MariaDB. The whole process is not complicated. Here we share the steps to migrate from MySQL to MariaDB in Ubuntu. Installation procedure: sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 0xcbcb082a1bb943db Modify /etc/a...

   MySQL,MariaDB,Ubuntu     2013-08-13 11:14:51

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