SEARCH KEYWORD -- Application Programming


  Introduction to the Application of eBPF in Golang

Most of the time, when we develop software or even use software, we play within the safe boundaries of the operating system. We might not know how the network interface welcomes that IP packet, nor how the filesystem handles the inodes when we save a file. This boundary is called user space, which is where we write applications, libraries, and tools. But there's another world, kernel space, where the operating system's kernel resides and is responsible for managing system resources such as memor...

   EBPF,GOLANG,GUIDE,APPLICATION     2024-10-02 08:46:37

  Why using + to concatenate string in Java loop is not a good option

String concatenation is a common operation in Java programming. It is to concatenate multiple strings into a single string. Java provides a String class which is an immutable class which means the object cannot be mutated once instantiated. Once a String object is instantiated, its properties cannot be changed anymore, so when concatenating strings, it's actually create a new String instance to store the concatenated string values. For example, below is a simple string concatenation example. Str...

   JAVA,STRING,JAVA 8     2019-01-18 22:07:12

  Google is returning back to China

It has been five years since Google announced its difficult decision to leave China in 2010. The well known reason was that Google didn't want to conform to China's censorship request on sensitive information. During these five years, many stories happened bbetween these two sides. Things may turn around now as there are a few indications where Google may return back to China at an appropriate time soon. The most convincing indication is that a customized Google play -- Google online shop may a...

   Google,China,Alphabet,Google play     2015-09-06 04:13:30

  Something you may not know about Shell

Shell is also called command line interface, it is the interface between *nix users and computer. Shell is a program which provides service to access OS kernel services. This article is to introduce some not so well known but useful and interesting knowledge about shell. Wiki shell was born almost at the same time as Unix. The first UNIX shell was written by Ken Thompson in 1971 and its name is Thompson sh. It's older than Linux kernel. The default Shell in most *nix and MacOS is bash, bash was...

   Linux, Unix,Shell,Command     2012-11-24 07:19:47

  Cripple Pachebel's Canon on Matlab

What can Matlab do? What the following Matlab code does is playing the piano music of Cripple Pachebel's Canon. You can have a try if you have Matlab installed on your computer. % Cripple Pachebel's Canon on Matlab % Have fun fs = 44100; % sample rate dt = 1/fs; T16 = 0.125; t16 = [0:dt:T16]; [temp k] = size(t16); t4 = linspace(0,4*T16,4*k); t8 = linspace(0,2*T16,2*k); [temp i] = size(t4); [temp j] = size(t8); % Modification functions mod4 =...

   Matlab,Programming,Canon,Music     2012-05-16 11:55:13

  Use DTrace to diagnose gdb issues

A few days ago, I installed the newest 64-bit gdb program (version 7.7.1) on Solaris 10 (X86_64 platform) to debug programs. After playing with the gdb a day, I found 2 issues about gdb:(1) The "set follow-fork-mode child" command doesn't take effect. By default, after the parent process forks the child process, the gdb will track the parent process, so this command can make gdb begin to follow the child process. But this command works OK on Linux.(2) The gdb can't parse the 32-bit application c...

   DTrace, debug, gdb, UNIX     2014-06-28 05:11:20

  Write Your Own R Packages

Introduction A set of user-defined functions (UDF) or utility functions are helpful to simplify our code and avoid repeating the same typing for daily analysis work. Previously, I saved all my R functions to a single R file. Whenever I want to use them, I can simply source the R file to import all functions. This is a simple but not perfect approach, especially when I want to check the documentation of certain functions. It was quite annoying that you can’t just type ?func&n...

   DATA SCIENCE,R PROGRAMMING,DATA ENGINEERING     2019-10-19 07:20:52

  Arrays.equals() vs MessageDigest.isEqual()

Both Arrays.equals() and MessageDigest.isEqual() are used to compare the equality of two arrays. They can be interchangeably in many cases. However, they do have some differences which lead to different use cases in real applications. One difference is that the arrays passed to MessageDigest.isEqual() cannot be null while it's ok for Arrays.equals(). The one major difference between these two methods is that Arrays.equals() is not time-constant while MessageDigest.isEqual() is time-constant. Thi...

   Arrays.equal(),MessageDigest.isEqual(),Java,Security     2015-05-14 22:03:29

  Resolve SystemStackError issue when resolving IP address in Ruby

In Ruby, Resolv is the default DNS resolution implementation. It can be used to resolve IP address of a hostname. To use it, one just needs to require 'resolv' in the code. But sometimes, a user would want to check /etc/hosts first or some other mechanisms to resolve an IP address. In this case, one can require 'resolv-replace' and then replace the default DNS resolvers with customized DNS resolvers. For example, using resolv-replace, one would write require 'resolv-replace' Resolv::DefaultResol...

   RUBY,RUBY ON RAILS,NETWORK     2017-07-08 09:54:35

  Twitter service down incidents summary

This Thursday, Twitter encountered a global service down incident. This is the second service down incident since last month. Later Twitter updated its website and stated that users might not be able to access Twitter temporarily.Twitter admitted the service down incident and explained that this time's service down was caused by problems of their both data centers.Ok, now lets summarize the service down incidents encountered by Twitter in past few years.in May 2008, Twitter's new engineer team w...

   Twitter,Service down,History     2012-07-28 12:36:39

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