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  ByteBuffer in Java

ByteBuffer is introduced in java.nio since Java 1.4. It provides a way of representing raw structured data such as from a file or from network. It enables fast access of underlying data compared to traditional ways like byte[] Prior to Java 1.4, if you want to represent a structured raw data, you need to create a byte[] and then having a set of checks to delimit the byte array to get the expected tokens. There are three ways to create a ByteBuffer: Wrapping an exiting array by calling ByteBuffe...

   JAVA,BYTEBUFFER,ALLOCATION     2015-07-08 03:17:44

  Flash Player sandboxing is coming to Firefox

Peleus here. In December of 2010, I wrote a blog post describing the first steps towards sandboxing Flash Player within Google Chrome. In the blog, I stated that the Flash Player team would explore bringing sandboxing technology to other browsers. We then spent 2011 buried deep within Adobe laying the groundwork for several new security innovations. Today, Adobe has launched a public beta of our new Flash Player sandbox (aka “Protected Mode”) for the Firefox browser....

   Flash,Sandbox,Google chrome     2012-02-07 06:16:57

  Let 's write some front end codes

I've seen a lot of arguments that there is no much technical value writing web portal, I think that the vast majority of good programmers will try many different things. The low level development and machine learning are not the only technologies which are  full of wisdom and challenges, I wrote web site for a few years, it is difficult to say that this is my initial interest, although I touched on other technologies as well, I still feel building website is challenging. Front end developme...

   Front end development, JavaScript,CSS     2013-01-22 04:00:24

  HTML5 Video and DRM

Many people call HTML5 an Adobe Flash replacement and I agree. Adobe already discontinued Flash on mobile devices. So HTML5 Video is a must for video on mobile phones and tablets. On the desktop Flash Video players are used more than HTML5 Video players but HTML5 video will work with a current web browser on a site that supports HTML5 video. Commercial video sites like YouTube will play partnered content in Flash even if you turned on HTML5 video at http://www.youtub...

   HTML5 Video,Flash,DRM,Comparison     2012-02-05 07:18:23

  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

  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

  Simple PHP paging class

Frequently in our web applications, we may have many records in the database to display. In order to imrpove loading speed and efficiency, we may need to display some records at a time, so we need to paginate the records. For example, if we have 1 million book records and when users want to view the book list, it's inefficient to display all the records on the same page, we may need to have some pagination to allow displaying a portion of the records such as 20 records per page. This is a simple...

   PHP,Paging,Class     2012-09-10 20:23:33

  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

  Roundup on Parallel Connections

A lot of blogging and follow-up discussion ensued with the announcement that IE8 supports six connections per host. The blogs I saw: IE8: The Performance Implications IE8 speeds things up IE8: 6 Connections Per Host IE 8 and Performance Testing IE8.s Connection Parallelism IE 8 Connection Parallelism Issues It’s likely that Firefox 3 will support 6 connections per server in an upcoming beta release, which means more discussion is expected. I wanted to pull all the facts into one place an...

   Browser,Concurrent connection,Persistent     2011-09-05 01:51:44

  Set up Superset on ubuntu 16.04 LTS

Apache Superset (incubating) is a modern, enterprise-ready business intelligence web application. Compared with business-focused BI tool like Tableau, superset is more technology-navy. It supports more types of visualization and able to work in distributed manner to boost the query performance. Most importantly, it is free of charge! An example dashboard: Let’s go and set it up. Create a virtualenv Assume Anaconda is installed for python management. # create a virtualenv with python 3.6 co...

   TUTORIAL,UBUNTU,SUPERSET     2019-10-19 21:34:55

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