https://clarkflybee.github.io/tags/file-system/ Recent content in File System on ClarkFlyBee's Blog https://clarkflybee.github.io/images/show.png https://clarkflybee.github.io/images/show.png Hugo -- 0.154.5 zh-cn 2026 ClarkFlyBee · GitHub Tue, 07 Apr 2026 14:43:01 +0800 https://clarkflybee.github.io/posts/2026-04-07-os-experiment-lab5-cheatsheet/ Tue, 07 Apr 2026 14:43:01 +0800 https://clarkflybee.github.io/posts/2026-04-07-os-experiment-lab5-cheatsheet/ <h2 id="实验5简单文件系统的实现">实验5：简单文件系统的实现</h2> <h3 id="基础架构与持久化层">基础架构与持久化层</h3> <h4 id="宏定义">宏定义</h4> <div class="highlight"><div class="chroma"> <table class="lntable"><tr><td class="lntd"> <pre tabindex="0" class="chroma"><code><span class="lnt"> 1 </span><span class="lnt"> 2 </span><span class="lnt"> 3 </span><span class="lnt"> 4 </span><span class="lnt"> 5 </span><span class="lnt"> 6 </span><span class="lnt"> 7 </span><span class="lnt"> 8 </span><span class="lnt"> 9 </span><span class="lnt">10 </span><span class="lnt">11 </span></code></pre></td> <td class="lntd"> <pre tabindex="0" class="chroma"><code class="language-c" data-lang="c"><span class="line"><span class="cl"><span class="cp">#define IMAGE_FILE &#34;fs.img&#34; </span><span class="c1">// 磁盘镜像文件名 </span></span></span><span class="line"><span class="cl"><span class="cp">#define BLOCK_SIZE 512 </span><span class="c1">// 每个数据块字节数（512字节，传统磁盘扇区大小） </span></span></span><span class="line"><span class="cl"><span class="cp">#define DATA_BLOCKS 1024 </span><span class="c1">// 数据块数量（1024个数据块，数据区512KB） </span></span></span><span class="line"><span class="cl"><span class="cp">#define MAX_FILES 256 </span><span class="c1">// 文件/目录数上限（DirEntry数组大小） </span></span></span><span class="line"><span class="cl"><span class="cp">#define MAX_OPEN_FILES 32 </span><span class="c1">// 同时打开文件数上限（OFT表大小） </span></span></span><span class="line"><span class="cl"><span class="cp">#define MAX_NAME_LEN 28 </span><span class="c1">// 文件名长度上限 </span></span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="cp">#define FAT_FREE (-1) </span><span class="c1">// FAT表空闲块标记 </span></span></span><span class="line"><span class="cl"><span class="cp">#define FAT_END (-2) </span><span class="c1">// FAT表链尾标记 </span></span></span><span class="line"><span class="cl"> </span></span><span class="line"><span class="cl"><span class="cp">#define FS_MAGIC 0x4D465331u </span><span class="cm">/* &#34;MFS1&#34; */</span><span class="cp"> </span></span></span></code></pre></td></tr></table> </div> </div><ul> <li> <p><code>FS_MAGIC</code> 用于识别文件系统格式，加载时校验合法性，防止用其他文件创建的文件误当作文件系统镜像。</p>