SEARCH KEYWORD -- PSEUDO RANDOM

  Cool HTML5 matrix effect

Do you still remember the movie The Matrix? Do you still remember the cool matrix effect in that movie? How is that effect achieved? Shaun Dunne shared a piece of HTML5 code which displays a cool matrix effect. The matrix demo can be found here. Below is the code which he achieves this effect: with var s = window.screen; var width = q.width = s.width; var height = q.height = s.height; var letters = Array(256).join(1).split(''); var draw = function () { q.getContext('2d').fillStyle='rgba(0,0,...

   Matrix,HTML5     2013-08-14 08:03:34

  FTP active mode and passive mode

1. What's active mode and passive mode a. FTP has two ports to control: Port 20 is for data transfer Port 21 is for control or establish TCP connection b. The process of active connection Note: C represents Client and S represents Server S opens port 20 and 21 C connects to port 21 of S with a random port, this port can be between 1024 and 65536, it sends port+x to server at the same time to specify C(X)->S(21) When S receives the command, it will sends back ACK, S(21)->C(X) S will set ...

   FTP,Active mode,Passive mode     2013-04-01 07:01:25

  Tips to improve JavaScript efficiency

Writing JavaScript code is tedious and error prone. You not only need to implement the necessary functions, but also need to ensure cross browser compatibility. This often causes the low efficiency of JavaScript developers. Here we recommend 12 tips you can benefit from. 1. Remove array element by index If we want to remove one element in an array, we can use splice. function removeByIndex(arr, index) { arr.splice(index, 1); } test = new Array(); test[0] = ’Apple’; test[1] = &rsq...

   JavaScript,Tips,Array     2013-07-27 20:50:40

  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

  Shell script common interview questions

Shell script is frequently used when monitoring system status on Linux. It's not an easy task to write shell script but it's a very important skill for developers and system administrators to ease work and automate common tasks. This post will share some common interview questions about shell script. 1. Get random characters(8 characters) Method 1 # echo $RANDOM |md5sum |cut -c 1-8 471b94f2 Method 2 # openssl rand -base64 4 vg3BEg== Method 3 # cat /proc/sys/kernel/random/uuid |cut -c 1-8 ed...

   LINUX,INTERVIEW,SHELL SCRIPT     2018-09-28 10:46:00

  The Problem With Client-Side Analytics

Client-side analytics is broken. The numbers produced by it are trivially spoofable by competitors and nefarious characters. Most websites use client-side analytics of one type or another and the only way to get numbers you can trust is to compare numbers from multiple providers and to take an average of the closest two.This post highlights the problem and proposes a partial solution that substantially mitigates the issues with minimal effort. Our proposed solution is simply to include a digital...

   Client side,Analysis,Problem,Tricks,ASP.NET,spoof     2011-10-22 12:58:51

  SkipList in Go

Algorithmic thinking is the must-have in the coding world, so I have been keeping the routine of algorithm practice every week, consolidating my knowledge of data structures on one hand, and improving my coding skills as well. A difficult one happened to be stuck in my mind- Implement SkipList with Go, which took me quite a weekend. Below is the front-line report of how I finally got the hang of it. First, from its concept. Wiki has explained it well. a skip list is a probab...

   GOLANG,SKIPLIST     2022-04-05 02:21:59

  RAM is the new disk...

Jim Gray, a man who has contributed greatly to technology over the past 40 years, is credited with saying that memory is the new disk and disk is the new tape. With the proliferation of "real-time" web applications and systems that require massive scalability, how are hardware and software relating to this meme? Tim Bray, in his discussions about grid computing before it became such a hot topic, pointed out how advances in hardware around RAM and networking were allowing for the creation...

   RAM,Flash,Memory,,Future,Disk     2011-08-12 07:34:27

  Ways to check existence of JavaScript object

The design of JavaScript is not so sophisticated. It's very easy for us to make mistakes if we are not very careful when using JavaScript. For example, to check the existence of JavaScript object. Now we want to check whether a global object myObj exists or not, if it doesn't exist, we declare it. The pseudo code for this is : if(myObj not exist){ declare myObj; } You may think it's very easy to write the code. In fact, it is much more difficult than we may think. Juriy Zaytsev says there are m...

   JAVASCRIPT,OBJECT,EXISTENCE     2020-09-12 02:14:02

  Google+ is sick

Google says that Google+ now has over 170million registered users, but according a new research report of Fast Company about Google+,  Google+ is just a virtual ghost town.This research selected a sample of 40,000 random Google+ users. The result is :The average post on Google+ has less than one +1, less than one reply, and less than one re-shareRoughly 30% of users who make a public post never make a second oneEven after making five public posts, there is a 15% chance that a user will not ...

   Google+,Sick,Research     2012-05-16 05:41:35

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