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  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

  Python Deserialization Attack Introduction: How to Build a Python Pickle Bomb

This article introduces an old and classic unsecured Python data serialization feature (the pickle library) and demonstrates how a red team attacker can exploit it to create a malicious binary or text data file that executes remote code or commands upon deserialization. The following attack flow diagram illustrates this process: We will follow 3 steps with the program code to show how Deserialization Attacks Work:   [ Step1 ] Crafting Malicious Data: An attacker crafts a malicious payloa...

       2024-07-07 03:08:22

  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

  What is cache penetration, cache breakdown and cache avalanche?

When designing and developing highly available system, cache is an very important consideration. It is useful to cache some frequently accessed data so that they can be accessed quickly and also cache can protect the downstream system like DB from being hit too often.  To provide better cache design in large systems, some problems may need to be considered first. In this post, we will talk about some frequently discussed cache problems and mitigation plans. Cache penetration Cache penetrati...

   SYSTEM DESIGN,CACHE PENETRATION,CACHE BREAKDOWN,CACHE AVALANCHE     2020-04-10 08:43:00

  Some famous article aggregators

Blogs are still very important places for people sharing their thoughts about something although some social media platforms have replaced some of these capabilities. As a blog writer, how can you let others know what you are thinking about? Besides your friends and social media platforms, there are some article aggregators around us which can help us promote our articles. Other than some aggregators like Google News, readers can submit articles to these sites themselves What are some famous art...

   News aggregator,Reddit,Digg,Hacker News     2013-08-12 03:34:37

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