SEARCH KEYWORD -- Turing machine

  Why Emacs?

PreludeIf you are a professional writer – i.e., if someone else is getting paid to worry about how your words are formatted and printed – Emacs outshines all other editing software in approximately the same way that the noonday sun does the stars. It is not just bigger and brighter; it simply makes everything else vanish.Neal StephensonIn the Beginning … Was the Command LineI’m an Emacs user and I’m proud of the fact. I know my reasons for using it (and loving i...

   Emacs,Linux,IDE,Editor,Usage     2011-11-21 10:22:05

  OT Railway System Development: How to Use PLC to Implement Land Based Railway Track Fixed Block Sign

Figure-00: Railway fixed block signaling system over view diagram, version v1.3 (2024) Project Design Purpose: This project aims to use Programmable Logic Controllers (PLC) with train detection sensors and train control signals to develop an automated OT system for railway track fixed block signaling control. The system will include a digital equivalent simulation to explain the logic of the track fixed block Automatic Train Control (ATC) mechanism for demonstration and training purposes. In th...

       2024-07-27 04:08:41

  Python and PLC Communication

This article provides detailed steps on how to use Python to communicate with Schneider M221 and Siemens S7-1200 PLCs via Ethernet. Additionally, we offer a packaged Python PLC client library, enabling you to easily build your own SCADA control programs, such as Human-Machine Interfaces (HMI). The system overview is shown below: To check the project detail please refer to Python Physical PLC Communication Clients # Created: 2024/06/29 # Version: v0.1.3 # Copyright: Copyright (c) 2024 ...

       2024-06-30 02:21:17

  2D Indoor CQB Robot Simulation

Program Design Purpose: The integration of robots in Close Quarters Battle (CQB) represents a significant advancement in modern military and law enforcement tactics. These robots, designed to navigate tight spaces, gather real-time intelligence, and engage threats, are invaluable assets in high-stakes scenarios. Our goal is to develop a 2D tactical board simulation system, similar to a computer game, that can load building floor blueprints, display CQB squad (robot) positions, enemy locations, ...

       2024-08-11 08:40:31

  4 deployment modes of Redis

As a high-performance in-memory database, Redis is widely used in current mainstream distributed architecture systems. To improve system fault tolerance, using multiple instances of Redis is also inevitable, but the complexity is much higher than that of a single instance. This article mainly introduces the four deployment modes of Redis and their advantages and disadvantages. Standalone Standalone mode is to install a Redis, start it, and business connects to it and that's all. The specific ...

   REDIS,STANDALONE,MASTER-SLAVE,SENTINEL,CLUSTER     2023-03-03 21:35:09

  Cross Browser HTML5 Drag and Drop

HTML5 Drag and Drop has been talked about a lot lately, but it’s hard to find really useful information about implementing it across multiple browsers.Mozilla, Apple and Microsoft all have pages describing how to use it, but their examples seem to work only in their particular browser (Apple’s example doesn’t even work in their own! Updated, Jan. 11, 2009: Although I have not been able to get this example working on Safari 2.0.4 and 3....

   HTML5,Drag and drop, Demo,Source code,Cr     2011-09-20 13:42:45

  PHP: a fractal of bad design

Preface I’m cranky. I complain about a lot of things. There’s a lot in the world of technology I don’t like, and that’s really to be expected—programming is a hilariously young discipline, and none of us have the slightest clue what we’re doing. Combine with Sturgeon’s Law, and I have a lifetime’s worth of stuff to gripe about. This is not the same. PHP is not merely awkward to use, or ill-suited for what I want, or suboptimal, or...

   PHP,Design,Analysis     2012-04-11 13:46:57

  Install and configure git plugin in Eclipse

When developing using IDE, it's always a good experience if everything can be done in the IDE including development, testing and version control. This also applies to Eclipse.  In this post, we will show the process of installing and configuring git plugin in Eclipse. The pre-requisite is that you have git installed on your local machine.  The detailed steps for installing and configuring git plugin are below. 1. Installing Git plugin Install using "Install New Software..." menu. ...

   ECLIPSE,GITHUB,GIT PLUGIN     2018-10-13 04:22:06

  Fix SSL 'alert protocol version' issue while git clone remote repository

Git provides ways to securely connect to remote repository and clone remote repository to local machine. This post will teach you how to fix the "SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version" issue while cloning a remote repository. The issue would look like: If this error occurs, it is most probably caused by out of date git version being used.To improve its security awareness, some weak cryptographic algorithms have been disabled and all git clients should upgrade to latest ones to acc...

   GIT,GIT CLONE,GIT SECURITY     2018-07-08 05:41:39

  Why (offset, limit) is slow in database select?

Starting from a problem Five years ago when I was working at Tencent, I found that MySQL request speed was very slow in the pagination scenario. With only 100,000 data, a select query on a single machine took about 2-3 seconds. I asked my mentor why, and he asked in return, "In an indexing scenario, what is the time complexity to get the nth largest number in MySQL?" The pursuit of the answer Confirming the scenario Assuming there is an index on the "status" column, a query like "select * from t...

   SLOW,LIMIT,OFFSET,MYSQL     2023-03-12 05:21:02

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