SEARCH KEYWORD -- SYSTEM CRASH


  Linux Clock : CST,UTC and NTP setup

1. There is an option when you set up clock on installing Linux: system clock users UTC, so what does UTC mean? It's Universal Time Coordinated(UTC), there are two different times in GPS system: one is UTC , the other one is LT(Local Time). The difference between these two is just the timezone difference, UTC is the time in timezone 0. If the local time in Beijing is 8 o'clock in the morning, then UTC time is 0 o'clock, which is a 8 hour difference. 2. In Linux, when we use date to check the tim...

   Linux,Clock,UTC     2013-03-21 12:19:30

  PHP to output string to client terminal

It is a common task to echo messages to the user using PHP. There are lots of ways where the message can be echoed to the client terminal(browser or console window) through PHP. These includes some well know debug methods like var_dump() and var_export() etc. In this post, we will show you some other methods shared by Laruence, one of the core members of PHP development team. 1. echo First comes with the most common one : echo. $str = "Hello PHP\n"; echo $str; 2. print Then comes another c...

   TRICKS,DEBUG,OUTPUT,PHP     2015-10-01 03:16:56

  Using MemoryMappedBuffer to handle large file in Java

When handling large files, it will largely affect the process speed while using traditional FileInputStream, FileOutputStream or RandomAccessFile since they trigger lots of read and write operations. In Java NIO, a new way of handling large file is introduced which is to use MmeoryMappedBuffer to create memory mapped file. Memory-mapped I/O uses the filesystem to establish a virtual memory mapping from user space directly to the applicable filesystem pages. With a memory-mapped file, you can pre...

   JAVA,IO,NIO     2015-11-13 01:58:08

  Unix directory hierarchy history

As a beginner user of Unix or Linux, people would frequently get confused about the use of different directories of the system.  For example, there is a /bin directory under root(/), it is used to store binary files. However, there are /usr/bin and /usr/local/bin under /usr which are used for storing binary files as well. Some systems even have /opt/bin. What are the differences among them? Though there are articles explaining different directories in *nix such as Filesystem Hierarchy Stan...

   UNIX,LINUX,FILESSYTEM,DIRECTORY HIERARCHY,HISTORY     2016-10-21 23:47:17

  Bill Gates : Ctrl+Alt+Del was a mistake

Microsoft chairman Bill Gates admitted that Ctrl+Alt+Del command was a mistake when he was in a fund raising campaign at Harvard University last week. This command was initially designed to reboot the system. David Rubenstein, the Harvard fund raising campaign chairman, asked Bill Gates : "Why when I turn on my software or computer do I need to have my three fingers to press control,alt and delete? Whose idea was that?" The answer given by Bill Gates is : "Basically because when you turn your co...

   Bill Gates,Ctrl-Alt-Del,Mistake     2013-09-26 23:28:37

  Eight C++ programming mistakes the compiler won’t catch

C++ is a complex language, full of subtle traps for the unwary. There is an almost infinite number of ways to screw things up. Fortunately, modern compilers are pretty good at detecting a large number of these cases and notifying the programmer via compile errors or warnings. Ultimately, any error that is compiler-detectable becomes a non-issue if properly handled, as it will be caught and fixed before the program leaves development. At worst, a compiler-detectable error results in los...

   C++,Compiler,Error detection     2012-04-08 09:55:20

  Differences between bashrc and profile in Linux

After login to a Linux system, the command console will show up with a prompt label such as # or ~, a shell command can be typed after this prompt and the system can execute the command thereafter. All these operations are handled by shell. Shell is a command language interpreter that executes commands read from the standard input device (keyboard) or from a file. There are different types of shells such as bash, ksh, csh etc. The most commonly used of them is bash and it's also the de...

   LINUX,PROFILE,BASH,BASHRC,.BASHRC,.PROFILE     2016-11-05 22:17:51

  One reason why mcrypt responds slowly

This morning one colleague came over and talked about one script which used mcrypt responded very slowly, the server configurations are fine. But the reason for the slowness is unknown. Here is one script which reproduces the issue: <?php $dmcryptText = "dummy"; $key = "foobar"; $size = mcrypt_get_iv_size(MCRYPT_BLOWFISH,MCRYPT_MODE_ECB); $iv = mcrypt_create_iv($size); //Take care $m = mcrypt_ecb(MCRYPT_BLOWFISH, $key, $dmcryptText, MCRYPT_DECRYPT, $iv); var_dump($m); When 20 requests of&...

   SOLUTION,SLOW,MCRYPT,RESPONSE,PHP     2012-09-27 12:03:16

  Microsoft's next generation OS Windows Blue may be free

In PC era, Microsoft is the world's largest software service provider, its revenue  is mainly from selling operating systems and other software services.With the advent of the era of mobile Internet, the free software service concept has been widely accepted, Microsoft has been forced to explore new business models.According to ZDNet, Microsoft's next-generation OS Windows Blue is expected to be released in mid of 2013. The biggest difference between the new version of the OS and the previ...

   Windows Blue, Pirce, Free     2012-11-29 10:54:15

  What is Deep Web- all you need to know about it?

Deep web is the most nefarious out of sight underground area that exists and not accessible to the public domain. The deep web sites cannot be accessed through standard search engines. Many experts believe to have compared this part of the internet hidden from paywalls and forms. The truth is that deep web is a hidden iceberg while the usual internet available to the public domain is just the tip of the iceberg. That part of what is available from search engines such as Bing or Google ...

   DEEP WEB,DARK WEB     2018-07-05 08:26:58

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