1. FreeBSD：
FreeBSD 是 FreeBSD 项目提供的免费开源操作系统。它是在两个类 Unix 操作系统 Berkeley Software Distribution (BSD) 和 Research Unix 的基础上设计的。它与 Linux 操作系统非常相似。它是早期著名的操作系统之一，但与其他操作系统相比，现在使用较少。 FreeBSD 的第一个版本于 1993 年推出。FreeBSD 的最新稳定版本是 12.1。
2. 安卓：
Android 是由谷歌提供的移动操作系统。它基于Linux内核和其他开源软件的修改版本。它专为智能手机和平板电脑等触摸屏移动设备而设计。它是使用 C、 Java、C++ 和其他语言开发的。 Android 的第一个版本于 2008 年由 Google 推出，最新的稳定版 Android 是 Android 10，完全免费提供。它是总体上使用最广泛的操作系统。
FreeBSD 和 Android 的区别：
| FreeBSD | Android |
|---|---|
| It was developed and is owned by The FreeBSD Project. | It was developed and is owned by Google LLC. |
| It was launched in 1993. | It was launched in 2000. |
| It is not designed for personal computers. | It is specifically designed for mobile devices. |
| Its target system type is server, workstation, NAS and embedded systems. | Its target system type is smartphones and tablet computers. |
| Kernel type is Monolithic with modules. | Kernel type is Linux-based. |
| Package management is Port collections and packages. | Package management is MSI or custom installer. |
| It is the most used operating system in personal computers. | It is the most used operating system overall. |
| Preferred license is BSD. | Preferred license is Apache 2.0 and GNU GPLv2. |