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  bash network interface

Some of us may have seen /dev/tcp/<host>/<port> before, is this a special file system implemented in some BSD kernel? Because there is no /dev/tcp in Linux. Actually, this one is implemented in bash. We no need to rely on wget,nc to do network connection. It's very easy to use this interface: bash-4.2$ cat </dev/tcp/time.nist.gov/13 56188 12-09-18 15:34:26 50 0 0 733.5 UTC(NIST) * bash-4.2$ exec 3<>/dev/tcp/www.w3.org/80 bash-4.2$ echo -e "GET / HTTP/1.0\n\n" >&3 b...

   Bash,Network interface,/dev/tcp     2013-07-20 00:57:52

  Java Cipher encryption/decryption example

In Java, Cipher is the API for doing data encryption/decryption. Many cryptographic algorithms such as AES, DES, RC4 etc can be specified when creating Cipher instance. The Cipher instance calls the underlying algorithm specific implementation to do the actual encryption/decryption.  Before doing the encryption/decryption, a key needs to be created and it will be used to do the encryption/decryption. A sample program for performing all these is : import java.security.Key; import javax.cryp...

   Java, Java Security, Cipher, Example, Sample     2015-08-14 07:07:10

  Android 4.0+ occupies quarter of Android market

Google updates its developer page about Android platform version market share. From the latest data, we can find Android 4.0 and above system occupy around 25% of all Android market. But Android 2.3 Gingerbread still occupies over 50% of Android market. From the above chart, Android 4.0 has 23.7% market share, the latest Android 4.1 JellyBean takes 1.8%, these two have 25.5% market share in total. But Android 2.3 Gingerbread alone still dominates the Android market, it takes 55.8% market share....

   Google,Android,Share     2012-10-02 19:22:19

  Origin of Windows blue screen

Many of you from old ages might see the classical blue Windows blue screen before.Do you still remember the most famous Windows blue screen incident during a presentation of a Windows 98 beta by Bill Gates at COMDEX on April 20 1998. But do you know the history of blue screen? John Vert, an ex-Windoes NT kernel guy, shared the story on Quora.  Back in 1991 John Vert wrote the original code for Windows NT 3.1 that put the video screen back into text mode and the routines to put text on it (a...

   Windows blue screen,History     2013-07-24 09:25:16

  Supervisord, God and Monit, which one to choose?

With the popularity of Docker, more and more service have been moved into docker containers and they are easy to build up and maintain for each atomic service(though it's a bit complex to maintain multiple docker containers which contain different service to form a complete solution). Ideally, each docker container should only contain one service which has only one running process. However, in reality there would be cases multiple processes would run in one single docker container and there is a...

   DEVOPS,MONIT,SUPERVISORD,GOD,DOCKER     2017-11-25 12:28:11

  4 asynchronous programming methods in JavaScript

You may know the execution environment of JavaScript is single threaded. The so called single thread means only one task can be running at any time, if there are many tasks, they need to be in a queue and wait for the previous task to be completed. The advantage of this mode is it's easy to implement and the execution environment is relative simple; the disadvantage is that if one task takes long time, the tasks following it must wait in the queue and this will delay other tasks consequently. Th...

   JAVASCRIPT,ASYNCHRONOUS PROGRAMMING, EVENT MODEL,PROMISE     2012-12-25 00:55:47

  The requirements of DevOps development

DevOps has become a popular and commonly adopted software development model in IT industry in recent years. Its popularity is partially because it advocates it could improve software development efficiency, delivery speed and cost saving. This is especially favored by managers who become the main force to promote this type of development model in their companies. However, we must be cautious about DevOps model as well. With their advantages, they also bring challenges to development teams and th...

   AGILE,DEVOPS,SPRINT     2018-06-03 23:18:44

  Some thoughts about Facebook native app

On Techcrunch Disrupt last month, Facebook CEO Mark Zuckerberg's remarks about their mobile app sparked a denunciation against Web App. HTML 5 seems to have become the bottleneck of poor experience of all related mobile applications. From the user perspective, Facebook native iOS App rates from the 1.5 star to four star now; since the introduction of new native app, the user usage is doubled. It's not easy to have a huge rise of user usage for such a big app like Facebook. Especially consid...

   Facebook, Native app, Analysis     2012-10-12 20:38:11

  Implementing DESede/ECB/NoPadding cipher algorithm in GoLang

By default, GoLang doesn't provide the ECB mode cipher for DESede though there is CBC mode provided. In cases we need to encrypt/decrypt data with ECB mode, we need to implement those by ourselves. This mode is frequently used when encrypting/decrypting PIN block which is small block data less than 16 bytes. In this post, we will introduce how to implement the DESede/ECB/NoPadding algorithm in GoLang by using the existing cipher support. Here we will not cover how DESede works in detail, instead...

   SECURITY,SAMPLE,GOLANG,DES,DESEDE,3DES     2019-07-29 06:43:50

  Recursive class initialization in Java

When a Java class is referenced and initialized, it has to go through the loading and linking first. Once the loading and linking complete successfully. The class will be initialized. The static variables and constant variables will be initialized during this process. Once the class is initialized, it is ready for use. If when class A is initialized and it is referencing a class B, the class B will also get initialized. But what will happen if class B is referencing class A as well? This is call...

   Java,JVM,class initialization,static final     2015-04-15 21:04:29

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