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  Some cases where MySQL cannot be started

After installing MySQL, when we try to start MySQL, sometimes we may not be able to start it. The reasons can be different. We share some general cases where MySQL cannot be started. Case 1: Directory or file permission issue If the permission is set wrongly in MySQL's $datadir and its sub directories or files, MySQL will not be able to read and write files normally. Error message: mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data /usr/local/mysql/bin/mysqld_safe: lin...

   MySQL,Error,Log     2013-08-15 03:32:36

  Guide for installing Ubuntu in VirtualBox on Windows

Have you ever tried to have two OSs installed on your PC? Do you want to try out the new Ubuntu system? If you do want to use Ubuntu when at the same time you are using Windows, you may want to install your Ubuntu in an VirtualBox. In this post, we will show you how to install Ubuntu in VirtualBox on Windows. Pre-requisites VirtualBox -- You can download it from Oracle. Ubuntu -- You can download it from here. Please note it should be an ISO file The Ubuntu used in this post is Ubuntu 12.04 LT...

   Ubuntu,Windows,VirtualBox     2014-01-15 03:21:05

  A HTTPS client and HTTPS server demo in Java

In this post, I will create a HTTPS server and HTTPS client demo which can establish HTTPS communication between a server and a client using Java. This should be very useful when we want to test our understanding about SSL communication. We will use both a detailed SSL client and a simple HttpsURLConnection as the HTTPS client. Before creating the actual HTTPS server and HTTPS client, we first need to generate the keystore and truststore to be used by the server and client. To generate the keyst...

   SSL,HTTPS,JAVA,DEMO     2015-10-23 09:04:36

  Apache Tomcat Installation and Configuration

When you want to install Apache Tomcat on Windows System. You may find that there are some tricky parts. Next I will elaborate the steps to install and configure Tomcat. If you want to install Tomcat as a service without GUI. You need to download the 32-bit Windows.zip from http://tomcat.apache.org/download-70.cgi. After downloading this zip file. You need to unzip this file to the directory which you want to put this software to. After unzipping, you can go to the bin directory and find t...

   Tomcat 7,Windows,Apache,Install,Configur     2011-04-10 14:17:21

  How to reset root password in MySQL 8

The user password in MySQL is stored in the user table, the password reset is actually to change the value of record in this table. To change the password in case the password is forgotten, the idea is to bypass the authentication of MySQL and get into the system and update the record password value with SQL command. In MySQL 5, one can start MySQL service with --skip-grant-tables option, this option will tell the service to skip loading the grant tables when starting, hence the root user can lo...

   MYSQL,PASSWORD,MYSQL 8     2018-12-24 21:27:13

  Different types of keystore in Java -- DKS

Domain KeyStore(DKS) is a keystore of keystore. It abstracts a collection of keystores that are presented as a single logical keystore. Itself is actually not a keystore. This new keystore type is introduced in Java 8. There is a new class DomainLoadStoreParameter which closely relates to DKS. To load different keystores into the single logical keystore, some configuration is needed. Here is the format of the configuration for grouping different keystores. domain [ ...] { keystore [ ....

   Java,keystore,DKS,tutorial     2015-01-20 02:27:27

  10 notorious computer virus

The history of computer virus is the same as computer history. With more and more powerful computers, virus also are smarter and harder to be detected and killed. They have big impact on data security and system usability. We introduce 10 notorious computer virus in the history. 1. Creeper In 1971, the Creeper virus, an experimental self-replicating program, is written by Bob Thomas at BBN Technologies. Creeper infected DEC PDP-10 computers running the TENEX operating sy...

   Computer virus,History,Security     2013-07-16 21:09:22

  What can we do about Facebook?

Around 4 years ago, we have posted an article Is Facebook becoming Tencent like? to analyze the strategy Facebook adopted to build its technology empire at that time. Today, we would continue this discussion since the story seems not end there. Facebook is still on the way of copying others. The latest victim being copied is Snapchat where lots of its new features have been copied by Instagram -- an app owned by Facebook. This has helped Instagram acquired lots of active users, especi...

   FACEBOOK,OPINION,SNAPCHAT,NEWS     2017-08-11 10:39:37

  Cache Reheating - Not to be Ignored

An important aspect to keep in mind with databases is the cost of cache reheating after a server restart. Consider the following diagram which shows several cache servers (e.g., memcached) in front of a database server.This sort of setup is common and can work quite well when appropriate; it removes read load from the database and allows more RAM to be utilized for scaling (when the database doesn’t scale horizontally). But what happens if all the cache servers restart at the same time, s...

   Database,Cost,Cache reheating,Advice     2011-09-21 09:47:29

  Lustre file system set for spit 'n' polish

Whamcloud, the startup created in July 2010 to continue development of the open source Lustre supercomputer file system, has secured a $2.1m contract from OpenSFS to spruce it up with new features and functions.Lustre – used on about 60 per cent of the largest supercomputers in the world – is a parallel clustered file system designed for both supporting petabytes of files and giving high-speed access to the data stored on the file system. Lustre was created by Peter Braam...

   TOP500,Cloud,Server,Database,Management     2011-08-25 08:25:14

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