SEARCH KEYWORD -- file system


  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

  How Java Application Developers Can Build Secure Internet Based Apps?

There are few compiled solution tested by experts to guide Java application development and maintenance team how they can start safe journey on Internet. Strong encryption, wise passwords, secure hardware are few of the tech tools that should be used by Java app development team to secure their Internet based apps.   The Internet is most amazing yet most risky platform where nobody knows either they are doing safe transaction on Internet or there is some dog watching out for data packets t...

   JAVA APPLICATION MAINTENANCE,JAVA APPLICATION DEVELOPMENT     2015-09-16 02:13:17

  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

  Browse OpenJDK Java source code in Eclipse

Java 8 was recently released, many developers are now trying to extract the source code of Java 8 to find out how the new added features such as Lambda expressions, default method in interfaces, new Time API are implemented. How do you manage to download and browse the source code? Today we are going to show how to extract OpenJDK Java source code to Eclipse. Since OpenJDK is adopting Mercurial as its distributed version control system, you need to install Mercurial on your computer first before...

   OpenJDK,Java 8,Source code,Eclipse     2014-06-16 00:53:34

  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

  Signature sign/verification demo in Java

Digital signature is commonly used in areas where data authentication and integrity are required. It is extremely important to have signature while transferring sensitive data from one peer to other peers through network since there might be malicious applications or man-in-the-middle attacks which may alter the data along the way. Java provides some APIs to generate and verify digital signature. One important class is Signature.  When generating the signature, a private key needs to be pa...

   SECURITY,JAVA,SIGNATURE     2015-11-21 09:48:12

  Python FTP Server and Client

Distributed Log File Automated Archive System This week, we will introduce the automated compute cluster nodes' log automated archive system project and FTP Communication utility library module. Program Design Purpose: This project aims to create an FTP server & client lib program for file transfer and a files management system for log data synchronization. We will develop an automated log file archive system that regularly collects newly generated log files from multiple nodes in a compute...

       2024-09-29 04:07:50

  Where Have You Installed Your Python Packages?

Preface I am writing this article because I recently noticed in the Python community that there are several frequently asked questions: Why does running the command after installing pip result in a "executable not found" error? Why does importing a module result in a "ModuleNotFound" error? Why can I run my code in PyCharm, but it doesn't work in the command prompt? Rather than just providing solutions, it is better to teach people how to fish. To address these types of issues, you need to und...

   PYTHON,PATH,PATH_PREFIX,PACKAGE LOCATION     2023-12-17 01:03:45

  Why can System.out.println be used to exit while loop

Let's first take a look at one simple Java thread code snippet which is supposed to exit the while loop after the first loop run. public class StopThread { private static boolean stopRequested; public static void main(String[] args) throws InterruptedException { Thread backgroundThread = new Thread(new Runnable() { @Override public void run() { int i = 0; while (!stopRequested) { i++; } } }); backgroundThread.start(); TimeUnit.SECONDS.sleep(1); stopRequested = true; } } But the tr...

   JAVA,THREAD,VOLATILE     2018-12-21 19:25:54

  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

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