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  Python SSH Connection Tools

Program Design Purpose: We aim to create a simple Python SSH tool library that facilitates SSH communication, SCP file transfer, and SSH port forwarding through multiple jump hosts in an SSH tunnel chain. The library is designed to provide a simple API for establishing nested SSH tunnel connections through multiple jump hosts with customizable TCP ports. This allows users or their programs to automate SSH tasks such as: Batch processing SSH connection tasks, such as connecting to multiple ser...

       2024-08-30 04:46:05

  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 ...

   PYTHON,PLC,COMMUNICATION     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

  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

  Find where the start up page is set in Firefox

Recently I encountered a weird behavior where a strange webpage showing up every time when I launched my Firefox. The first thought came into my mind is that my homepage of Firefox had been tampered. It might be changed because some software changed my browser settings to promote something. So the next immediate thing I went to check was to see my Firefox browser settings. To my surprise, the homepage setting was not touched. It would still open the Momentum screen which would display some beaut...

   WINDOWS,FIREFOX,HOMEPAGE,STARTUP PAGE,HAO123     2021-10-02 02:28:53

  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

  Certificate is invalid for localhost in Chrome

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   CHROME,LOCALHOST,HTTPS,CERTIFICATE,ELASTICSEARCH     2022-03-16 08:21:27

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