☁️ 云计算：租一台"云上的电脑"☁️ Cloud Computing: rent a computer in the sky

上一片搜到的竹子知识，存在哪？💻 小电脑自己的硬盘太小——于是它向云端租了一台电脑，这就是云计算。 Last leaf, where do the bamboo facts live? 💻 Little Computer's own disk is too small — so it rents a computer in the sky. That's cloud computing.

第 1 步：云是别人的电脑Step 1: The cloud is someone else's computer

云到底是什么？一句话：租来的电脑。What is the cloud, really? In one line: a rented computer.

我的电脑 vs 云端机房，租来用 — 左边是我的电脑，又小又满。右边是云端机房，成排的服务器。中间大箭头写着：租来用。存文件、跑程序，都能租。 Left: my computer — small and full. Right: the cloud data center — rows of servers. The big arrow says: rent it. Store files, run programs — all rentable.

租也有三档：毛坯、精装、酒店，你选哪档？Renting comes in three levels: bare, furnished, hotel — which floor is yours?

第 2 步：租房三档Step 2: Three rental levels

三档：IaaS 毛坯房，PaaS 精装房，SaaS 酒店 — IaaS 租毛坯房：只给空机器，系统自己装。PaaS 租精装房：环境配好了，直接开发。SaaS 住酒店：拎包入住，网盘文档打开就用。 IaaS is a bare flat: empty machine, install it yourself. PaaS is a furnished flat: ready to build in. SaaS is a hotel stay: walk in — drives and docs just work.

云虽好，有个命门：没网就罢工。The cloud is handy — with one weak spot: no network, no service.

第 3 步：断网那天Step 3: The day the network died

断网了，云服务罢工，本地还能用 — 断网了，云服务全睡着：网盘、文档、游戏都打不开。之前存在本地的照片，还能看。记住：重要的东西，本地也留一份。 Offline, cloud services nap: drives, docs and games won't open. Photos saved locally still show. Rule: keep a local copy of what matters.

🎮 本地还是云端？（30 秒）🎮 Local or cloud? (30 seconds)

道理讲完了。4 个任务：存照片、坐飞机、跑大程序、断网改文档——帮小电脑选一边。Theory done. Four jobs — photos, a flight, a heavy program, an offline doc — pick a side for Little Computer.

一句话记住它：云 = 租别人的电脑；地方不够、算力不够就租；断网那天，还得靠本地。 Remember it in one line: cloud = renting someone else's computer; short on space or power, rent; when offline, trust local.

云 = 别人的电脑：存文件、跑程序，都能租来用Cloud = someone else's computer: files and programs, all rentable 三档：IaaS 毛坯 / PaaS 精装 / SaaS 酒店（网盘文档就是它）Three levels: IaaS bare / PaaS furnished / SaaS hotel (drives and docs live here) 断网云罢工：网盘文档游戏都要网；重要的本地留一份Offline, cloud naps: drives, docs, games need network; keep a local copy

内容参考 OpenStax 等公开教材，多来源核对 · AI 生成、人工审核 · 发现错误欢迎指正，帮这片叶子长得更好。 Based on OpenStax and other open textbooks, cross-checked across sources · AI-generated, human-reviewed · Spotted a mistake? Tell us — help this leaf grow.