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Html Test

html01 <!DOCTYPE html> <html lang="zh"> <head> <meta charset="UTF-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <title>俄罗斯方块</title> <style> canvas { border: 1px solid black; display: block; margin: auto; } </style> </head> <body> <canvas id="tetris" width="300" height="600"></canvas> <script> const canvas = document.getElementById("tetris"); const context = canvas.getContext("2d"); const ROWS = 20; const COLS = 10; const BLOCK_SIZE = 30; // 创建一个空的游戏区域 let board = Array.from({ length: ROWS }, () => Array(COLS).fill(0)); const shapes = [ [[1, 1, 1, 1]], // I [ [1, 1, 1], [0, 1, 0], ], // T [ [1, 1, 0], [0, 1, 1], ], // S [ [0, 1, 1], [1, 1, 0], ], // Z [ [1, 1], [1, 1], ], // O [ [1, 0, 0], [1, 1, 1], ], // L [ [0, 0, 1], [1, 1, 1], ], // J ]; let currentShape; let currentPosition; function randomShape() { const index = Math.

Take a Btrfs Snapshot

System snapshot is a crucial tool for data protection and system recovery. Today, I will start with COW file system, introduce four key features of Btrfs, and explain how to use Btrfs to take snapshots of your system. Copy-On-Write Copy-On-Write (COW) is an efficient storage management technique that ensures data integrity and optimizes storage utilization. When two processes simultaneously read the same data block in a COW file system, the system ensures that both processes access the same data block.

Redis Enables Activedefrag

Redis is a widely used in-memory database, renowned for its speed and efficiency. However, prolonged usage can lead to memory fragmentation issues, impacting performance and efficiency. In this blog post, we’ll explore Redis memory fragmentation using a vivid analogy and discuss how Redis’ active defragmentation feature can mitigate these issues. The Courier Box Anology Imagine Redis’ memory space as a courier box used for storing items. Initially, the box is neatly organized, efficiently storing items of various sizes.