SEARCH KEYWORD -- Bit operation


  The evolving history of asynchronous operation in JavaScript

JavaScript is single threaded, it means there would be only one task running at any point of time. But this would slow down the overall program execution if there is long running task, hence asynchronous task execution is desired in complex cases. To achieve asynchronous task execution, there are a few options introduced in JavaScript. setTimeout/setInterval Event Promise Async/Await setTimeout/setInterval is one of the first mechanisms introduced in JavaScript to simulate asynchronous operati...

   JAVASCRIPT,ASYNC,PROMISE,AWAIT     2019-11-09 08:21:56

  Implementation of +,-,*,/ with bitwise operator

There is a question asked on Stackoverflow : Divide a number by 3 without using *,/,+,-,% operators. This question is an Oracle interview question. Some people give excellent answers. You can go there and take a look. Usually we need to use bitwise operators to do this kind of implementations. Here I want to show you ways to implement +,-,*,/ with bitwise operators. A bitwise operation operates on one or more bit patterns or binary numerals at the level of their individual bits. It is a fast, pr...

   Bitwise operator,Shift,Add,Subtract,Multiplication,Division     2012-08-05 01:52:47

  About tmpfs

tmpfs is another confusing name in Linux kernel, its implementation is in mm/shmem.c, shmem has no relation to tmpfs at first glance although we know tmpfs is based on memory. We can understand why we use this name by seeing where this is used. In a desktop Linux system, tmpfs is loaded usually: % grep tmpfs /proc/mountsdevtmpfs /dev devtmpfs rw,seclabel,nosuid,relatime,size=1958956k,nr_inodes=489739,mode=755 0 0tmpfs /dev/shm tmpfs rw,seclabel,nosuid,nodev,relatime 0 0tmpfs /run tmpfs rw,seclab...

   tmpfs,Linux,file system     2013-06-14 12:10:56

  Mac shortcut key cheatsheet

More and more people are using Mac computers or switch from Windows or other OS to MacOS, there are lots of shortcut keys which can help improve the work efficiency or ease operations. This post will try to list some commonly used shortcut keys in Mac. But before that, let's first know some common keys on a Mac computer keyboard. There are four major function keys: Command, Control, Option and Shift. Most of the shortcut keys will combine the functional key and other key. Basic Command key is t...

   SHORTCUT,SCREENSHOT,COMMAND,SHORTCUT KEY,MACOS     2019-02-05 07:13:06

  How to optimize MySQL insert statement

For a big data system, one problem is the data access efficiency, one more problem is that the data insertion is very slow. We had a service system, the data loading process would take 4-5 hours. This time consuming operation is risky since if the program is interrupted during the loading process, it might be rerun, this will be troublesome. So it's necessary to improve the insertion efficiency for big data systems. Here we provide two optimization suggestions. 1. Combine multiple insert stateme...

   MySQL,insert,optimization     2012-10-24 22:03:13

  Check file readability in Java

File operation is quite platform dependent. Although Java is a cross platform programming language, the file operation in Java is also platform dependent. The obvious evidence is the file permission check. In Java, we can call canRead(), canWrite() and canExecutable() to check whether the program can read, write or execute the file specified. However, on Windows, when we call canRead() on a File object, we may get unexpected result. Actually, on Windows, when we call canRead() on a File object, ...

   Java,Files,Readable,Check     2013-12-05 06:10:15

  VirtualBox Q&A(Host OS: Windows; Guest OS: Ubuntu)

This is a Q&A post after sharing Guide for installing Ubuntu in VirtualBox on Windows 1. If the resolution of the installed guest OS on the VirtualBox is too small(For example 640x480) and you cannot adjust it through System Settings -> Display, what should you do? A: In this case, it is mostly probably you don't have the VirtualBox Guest Additions installed. You can install the Guest Additions on your guest OS by: sudo apt-get install virtualbox-guest-dkms Then restart the VM and you wil...

   VIRTUALBOX,HOST ONLY,RESOLUTION,Q&A,STATIC IP     2016-08-12 04:24:40

  Stream API in Java 8

Overview In this lesson on Stream API in Java, we will study how we can put Streams to use to write efficient and much more maintainable code. We will also write code with and without Streams so that we are able to compare the two versions. Before doing all this, we must know how to create a Stream and process it and that is what we will get started with. Introduction to Streams We will be starting with creating Streams. Let us get started with the Stream<T> API which enables us to play w...

   STREAM API,JAVA 8,DEVELOPMENT,TEAM     2018-01-30 00:14:46

  Embrace open source

In past few days, there are many tech news which are related to open source. For example, Microsoft enables Linux on its Windows Azure cloud, Facebook open sourced its C++ library Folly and Samsung joined Linux foundation. Now more and more big companies realize the power of open source and are willing to contribute to the open source community. It will benefit not only developers but also these big companies as well.By providing some open source libraries or projects, developer may reduce their...

   Open source,Microsoft,Samsung,Facebook,Linux     2012-06-06 05:37:59

  4 asynchronous programming methods in JavaScript

You may know the execution environment of JavaScript is single threaded. The so called single thread means only one task can be running at any time, if there are many tasks, they need to be in a queue and wait for the previous task to be completed. The advantage of this mode is it's easy to implement and the execution environment is relative simple; the disadvantage is that if one task takes long time, the tasks following it must wait in the queue and this will delay other tasks consequently. Th...

   JAVASCRIPT,ASYNCHRONOUS PROGRAMMING, EVENT MODEL,PROMISE     2012-12-25 00:55:47

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