# Page Not Found

The URL `freebsd-qi-kan/2025789-qian-ru-shi/embedded-freebsd-looking-back-and-forward` does not exist. This page may have been moved, renamed, or deleted.

## Suggested Pages

You may be looking for one of the following:
- [2.4 FreeBSD 简史](https://book.bsdcn.org/di-2-zhang-freebsd-dao-lun/di-2.4-jie-freebsd-jian-shi.md)
- [2.3 FreeBSD 开发模型](https://book.bsdcn.org/di-2-zhang-freebsd-dao-lun/di-2.3-jie-freebsd-kai-fa-mo-xing.md)
- [FreeBSD 开发参与指南](https://book.bsdcn.org/fu-lu-i-gong-ju-yu-zi-yuan/freebsd-kai-fa-can-yu-zhi-nan.md)
- [7.2 使用 freebsd-update 更新 FreeBSD](https://book.bsdcn.org/di-7-zhang-freebsd-xi-tong-geng-xin/di-7.2-jie-shi-yong-freebsd-update-geng-xin-freebsd.md)
- [6.2 FreeBSD 软件源](https://book.bsdcn.org/di-6-zhang-ruan-jian-guan-li/di-6.2-jie-freebsd-ruan-jian-yuan.md)

## How to find the correct page

If the exact page cannot be found, you can still retrieve the information using the documentation query interface.

### Option 1 — Ask a question (recommended)

Perform an HTTP GET request on the documentation index with the `ask` parameter:

```
GET https://book.bsdcn.org/di-2-zhang-freebsd-dao-lun/di-2.4-jie-freebsd-jian-shi.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

### Option 2 — Browse the documentation index

Full index: https://book.bsdcn.org/sitemap.md

Use this to discover valid page paths or navigate the documentation structure.

### Option 3 — Retrieve the full documentation corpus

Full export: https://book.bsdcn.org/llms-full.txt

Use this to access all content at once and perform your own parsing or retrieval. It will be more expensive.

## Tips for requesting documentation

Prefer `.md` URLs for structured content, append `.md` to URLs (e.g., `/di-2-zhang-freebsd-dao-lun/di-2.4-jie-freebsd-jian-shi.md`).

You may also use `Accept: text/markdown` header for content negotiation.