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  7 misunderstandings of DNS resolution

DNS resolution is generally considered as providing mapping between domain name and IP address, for example www.google.com maps to 74.125.71.103. There are two important reasons for doing DNS resolution: IP address is hard to remember, while domain name is human friendly Virtual host may access different contents according to the header of the host domain name(sub-domain name) Some webmasters may have some unreasonable requirements when doing DNS resolution. It mainly because they are not very...

   DNS resolution,misunderstanding     2012-10-20 12:57:16

  Be careful when running knife vault command

While using Chef, one would frequently use knife commands which are used to manage resources on the Chef server. One can list all nodes, data bags, vault items and many other stuff on the Chef server. In this post, we would cover one command which may need your attention when using it -- knife vault. On Chef server, one can store data to data bags which can be accessed by registered clients. These data bags usually store the data in plain text format. In some cases, one would need to store data ...

   KNIFE VAULT,KNIFE DATA BAG,CHEF-VAULT,CHEF     2017-08-19 00:26:54

  JavaScript JVM runs Java

The world of software is made slightly crazy because of the huge flexibility within any computer language. Once you have absorbed the idea of a compiler written in the language it compiles what else is there left to gawp at? But... a Java Virtual Machine JVM written in JavaScript seems like another level of insanity.In fact it is a quite reasonable idea which is only made mad by the usual positions that Java, the top dog, and JavaScript the underling, usually occupy. Java is compiled not to mach...

   JavaScript,JVM,BicaVM,Cross platform,JavaScript written JVM     2011-11-22 02:51:38

  What happens on the Internet in one minute?

In one minute, 216,000 images are shared on Instagram, $83,000 sales happen on Amazon, 1.8 million Likes are clicked on Facebook, also 72 hours videos are uploaded to YouTube. This image is from Omee and it shows us what happens on the Internet in one minute. For example, how many Tweets are posted, how many pictures are viewed, how many minutes communication through Skype. The data on the graph is from PC Mag, Business Insider and other websites. In one minute, 2 million searches on Google, 70...

   Infographic,60 seconds,Internet     2013-08-01 06:47:51

  Generate certificate in Java -- Store certificate in KeyStore

In previous post, we have explained how to create a certificate chain in Java. After generating the chain, we need to store it somewhere so that it can be used later when we are doing the actual SSL communication, either in a key store or trust store. This post will show you how to store the private key and its associated certificate chain in a keystore file. There are different types of keystore in Java, in this post, we will choose the JKS to demonstrate how to store the certificate chain. Whe...

   Java,Certificate chain,Keystore     2014-08-20 03:56:39

  How does GoLang know how many CPUs to use?

When running lscpu command on Linux, it will list the CPU info on the machine. Take one example where there is one CPU with 2 cores and each core has two threads which indicates there are 4 cores available. Now let's see how many cores GoLang program would identify. From output, NumCPU and GOMAXPROCS both output 4 which is expected. How does go runtime get this info, does it get it through similar command like lscpu or /proc/cpuinfo? Let's dig more in GoLang's source code. In runtim...

   GOLANG,CPU,NCPU     2020-12-29 23:22:15

  Forgotten TODOs: ideas for contributing to open-source projects

I often talk to students that want to contribute to open-source projects, but just don't have an idea what to work on. Here's a tip if you're in a similar situation (e.g. you want to apply for GSOC) : 1 git clone repository_url_of_some_open_source_project target_directory 2 grep -RIn TODO target_directory/* So, find the URL of the repository project you want to contribute to, checkout the repository using git/mercurial/svn and then find all the TODOs in the source code using grep. The -RI...

   Open source,constribution,TODO,participation     2012-03-03 22:30:28

  etcd installation and usage

etcd is an open source and highly available distributed key-value storage system and is commonly used in critical data storage and service discovery and registration use cases. It is focusing on: Simple: well-defined, user-facing API (gRPC) Secure: automatic TLS with optional client cert authentication Fast: benchmarked 10,000 writes/sec Reliable: properly distributed using Raft etcd and Redis both support key-value storage and can be set up in distributed systems. Also Redis supporst more key...

   ETCD,TUTORIAL,RAFT,DISTRIBUTED SYSTEM     2021-03-07 03:10:33

  Welcome the new Google logo

Google today changed their logo, the new logo adopts the flat design with a lighter color scheme. Apart from these, there are no major changes on the font style, character color etc. Old logo New logo Along with the new logo, Google also released a new navigation menu that sits next to the Share and account info. The launcher, which looks just like the app launcher on Chrome OS, brings up an App grid with your favorite Google services. Actually, Google wanted to replace the top black navigati...

   Google logo,Chrome OS,App menu     2013-09-19 23:06:36

  Create temp file in Bash using mktemp and trap

When working on Linux Bash, sometimes there is need to create temporary file. A common way of creating temp file on Linux is creating some file in /tmp directory. However there is security risk when creating temp file in /tmp directory. This post will show how to securely create temp file in Linux Bash. When creating file in /tmp directory, there are some security risks. This directory can be accessed by any user on the system, any user can write data into this directory as well. The files creat...

   LINUX,MKTEMP,TRAP,TEMP FILE     2019-12-30 23:28:23

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