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  How does computer boot up?

The whole boot process of computer can be summarized in 4 phases. 1. BIOS In the 70's  read-only memory(ROM) was invented. The boot program is written into ROM, the first thing the computer does is to read and execute this program when it's powered on. The program in this chip is called "Basic Input/Output System" (BIOS). 1.1 Power-On Self-Test The BIOS will first check whether the computer hardware can fulfill the basic conditions for booting up, this process is called Power-On Self-Test...

   Computer, boot, partition     2013-02-23 23:19:47

  Understanding GoLang interface

If goroutine and channel are considered as the foundation for GoLang concurrency, interface would be the key for data types in GoLang. In practical Go programming, almost all data types are built/used around interfaces, interface is the core of GoLang data structures. Go is not a typical OOP language, it has no class and inheritance concept syntactically. But it doesn't mean that there cannot be polymorphism in GoLang. Because of interface, it achieves the same polymorphism effect as in C++, tho...

   INTERFACE,GOLANG     2021-05-15 04:16:42

  Set PHP session timeout

There are many different discussions about PHP sessions. We may often face some weird issues while handling PHP sessions. Sometimes session is expired earlier than expected. Or sometimes the session is not expired. This introduces many confusions. Today we discuss how to set PHP session timeout correctly today. In php.ini, there are three key parameters which will affect the session timeout. session.gc_maxlifetime, session.gc_probability and session.gc_divisor. session.gc_maxlifetime defined the...

   PHP,session,timeout     2013-08-31 08:11:03

  Why are column oriented databases so much faster than row oriented databases?

I have been playing around with Hybrid Word Aligned Bitmaps for a few weeks now, and they turn out to be a rather remarkable data structure.  I believe that they are utilized extensively in modern column oriented databases such as Vertica and MonetDB. Essentially HWABs are a data structure that allows you to represent a sparse bitmap (series of 0's and 1's) really efficiently in memory.  The key trick here is the use of run length encoding to compress the bitmap into fe...

   Database,Column oriented,Speed analysis,Vertica     2012-01-29 04:27:05

  Jelly Bean becomes the most popular Android OS

Google released the latest Android usage stats on Monday. Jelly Bean becomes the most popular Android OS for the first time. It takes 37.9% Android market share(32.3% from 4.1.x and 5.6% from 4.2.x). Ginegerbread is at the second place and it has 34.1% Android market share. This is a good news to many Android developers as they can use many new features provided in the new system if there are more and more users are using the new OS. Also if Google wants to attract news users, they have to enco...

   Android,Jelly Bean,Usage     2013-07-09 04:52:28

  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

  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

  Many Chinese applicants to US universities may be affected by Gmail cut out

Just after Christmas, many Chinese found that they could not connect to Gmail anymore in mainland China. Since Google announced leaving from China in 2010, the web version of Gmail was not accessible anymore. But people from China could still access Gmail through some Gmap apps. This time, Gmail is not accessible even with these apps. It is said that all the mail service protocols of Gmail including IMAP/POP/SMTP have been cut out by Chinese government. This means no mails can be sent to or rece...

   Gmail, China, Gmail cut out     2014-12-30 00:35:28

  Google.com is considered as partially dangerous by Google

Google has a service called Transparency Report which is to examine billions of URLs per day to identify dangerous pages which may trigger downloading of malicious software.  When you search a site, it will give the status of the site and also the safety details of the site if there are potential dangerous pages on the site.  These details will help the site owners to identify the potential issues and fix them as early as possible, Embarrassingly when searching for Google.com, it is c...

   GOOGLE,GOOGLE.COM     2016-04-20 00:38:15

  WeChat has 100 million international users now

Just one month ago, Tencent announced that it had 70 million international users outside of China mainland. Today, they announced that WeChat hit 100 million international users. In just one month, the international users increase by 30 million. WeChat becomes one of the most tough competitors in the international IM market. Although there are still Whatsapp, Line and some other IMs, WeChat provides many different robust features, especially in the newly released WeChat 5. The new features in W...

   WeChat,Tencent,Internationalization     2013-08-20 02:38:14

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