SEARCH KEYWORD -- string


  CASSANDRA data model

Cassandra is an open source distributed database, it combines dynamic key/value and column oriented feature of Bigtable. Features of Cassandra are: Flexible schema, no need to design schema first, it's very convenient to add or delete strings Support range search on keys High usability, extensible. The single node error will not affect the cluster. We can think Cassandra's data model as a 4 or 5 dimensional Hash. COLUMN Columns is the smallest data unit in Cassandra, it is a 3 dimensional data...

   Cassandra,database,sort     2013-06-08 22:07:40

  Set Real-Time Clock Unit for OT/IoT Device

Configure DS1307 RTC on BeagleBone-Black Arduino or Raspberry-PI Figure-00: Project Overview Diagram , version v0.1.2 (2024) Program Design Purpose: Real-Time Clock (RTC) modules are essential for maintaining accurate timekeeping in various applications, including system clocks, data logging, and alarm systems. In scenarios where devices operate offline, such as a ship's NMEA 0183 data recorder that logs engine and rudder data, or an RTU (Remote Terminal Unit) with real time state change config...

       2024-08-18 03:09:06

  Tips to improve JavaScript efficiency

Writing JavaScript code is tedious and error prone. You not only need to implement the necessary functions, but also need to ensure cross browser compatibility. This often causes the low efficiency of JavaScript developers. Here we recommend 12 tips you can benefit from. 1. Remove array element by index If we want to remove one element in an array, we can use splice. function removeByIndex(arr, index) { arr.splice(index, 1); } test = new Array(); test[0] = ’Apple’; test[1] = &rsq...

   JavaScript,Tips,Array     2013-07-27 20:50:40

  Load and execute JavaScript

When we load and execute JavaScript in a webpage, there are many points we need to care about because of its design and feature. There are two features about JavaScript execution in a browser: 1). The JavaScript codes will be executed immediately once loaded;2). When JavaScript codes are being executed, they will block the following contents (including page rendering and other resources downloading). So if there are multiple js files to be loaded, these codes will be executed sequentially. Since...

   JavaScript,async,defer,load,execute     2013-06-07 04:53:46

  Python PLC Honeypot: Env Deployment And Attack Detection

In the previous article, we introduced the design of Python PLC Honeypot Project, this article will provide detailed step-by-step instructions on how to deploy and use the honeypot system in your environment for detecting potential attacks on OT (Operational Technology) networks. The article includes three main section:   Design of Attack Alert and Notification Function Honeypot deployment: an example deployment of a mixed OT protocol honeypot, consisting of a simple setup with...

       2024-12-01 00:27:33

  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

  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

  A Sip of Go Log

Logging is indispensable in any code that we need its support both in debugging and in statistics. However, a package that filled withfmt.Println/fmt.Printf printing various messages can never be considered a read-to-be-adopted package, which can be optimized by a simple change, using Golang’s native log package to print information to standard output or to a file. Then, how to apply the log package? Are there any limitations? If so, can we seek open-source packages? Let&rsq...

   GOLANG,LOGGING     2022-06-16 05:43:24

  Something you may not know about Shell

Shell is also called command line interface, it is the interface between *nix users and computer. Shell is a program which provides service to access OS kernel services. This article is to introduce some not so well known but useful and interesting knowledge about shell. Wiki shell was born almost at the same time as Unix. The first UNIX shell was written by Ken Thompson in 1971 and its name is Thompson sh. It's older than Linux kernel. The default Shell in most *nix and MacOS is bash, bash was...

   Linux, Unix,Shell,Command     2012-11-24 07:19:47

  PHP to integrate with Sign in with Google

Google has a huge user base and hence it provides an authentication service for third party service to integrate with them so that people can sign in with Google in their services. Google also adopts OAuth 2 to provide this kind of Open ID connect service. This post will introduce how to integrate with sign in with Google functionality in your PHP website.  Create a client app on Google The first step you should follow is to create a Google app, you can follow the post here to create the p...

   PHP,GOOGLE API,OPEN API,SIGN IN WITH GOOGLE     2019-03-03 02:00:09

RECENT