1. FreeBSD：
FreeBSD是FreeBSD项目提供的一个免费的开源操作系统。它是基于两个类似Unix的操作系统Berkeley Software Distribution(BSD)和Research Unix设计的。它与Linux操作系统非常相似。它是较早的著名操作系统之一，但是现在与其他操作系统相比，它的使用率有所降低。 FreeBSD的第一个版本于1993年发布。FreeBSD的最新稳定版本是12.1。
2. Android：
Android是Google提供的移动操作系统。它基于Linux内核和其他开放源代码软件的修改版。它是专为智能手机和平板电脑等触摸屏移动设备设计的。它是使用C， Java，C++和其他语言开发的。 Google于2008年推出了第一个Android版本。最新的稳定版Android是Android10。它完全免费提供。总体来说，它是最常用的操作系统。
FreeBSD和Android之间的区别：
| 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. |