1. iOS：
iOS是苹果公司提供的移动操作系统。它主要是为iPhone和iPod Touch等Apple移动设备设计的。它以前被称为iPhone OS。它是基于Darwin(BSD)操作系统的类Unix操作系统。它是仅次于Android的世界第二使用最多的移动操作系统。它主要用C，C++，Objective-C，汇编语言和Swift编写。 iOS的第一个版本于2007年发布。
2. DragonFlyBSD：
DragonFly BSD是由Matthew Dillon开发的免费开源操作系统。它是一个类似Unix的操作系统，其设计灵感来自FreeBSD操作系统。它基本上不用于个人计算机。它是专门为服务器，工作站，NAS和嵌入式系统设计的。主要使用的编程语言是C语言。 DragonFly BSD的第一个版本于2003年发布。它具有Hybrid内核。
iOS和DragonFlyBSD之间的区别：
| S.No. | IOS | DRAGONFLYBSD |
|---|---|---|
| 1. | It was developed and is owned by Apple Incorporation. | It was developed by Matthew Dillon. |
| 2. | It was launched in 2007. | It was launched in 2003. |
| 3. | Its target system types are smartphone, music player and tablet computer. | Its target system types are workstation, server, NAS and embedded systems. |
| 4. | Computer architectures supported by iOS are ARMv8-A (iOS 7-present), ARMv7-A (iPhone OS 3-iOS 10) and ARMv6 (iPhone OS 1-iOS 4.2.1). | Computer architectures supported by DragonFlyBSD is x86-64. |
| 5. | It does not have package management. | Its package management is dports or pkg. |
| 6. | Its native APIs are Cocoa and BSD-POSIX. | Its native APIs are BSD/POSIX. |
| 7. | It has preferred license is Proprietary, APSL and GNU GPL. | It has preferred license of BSD. |
| 8. | Its update management is Software Update. | Its update management are git, cvsup, rsync and pkg. |
| 9. | File systems supported by iOS are HFS+ and APFS. | File systems supported by DragonFlyBSD are UFS1, MFS, ext2, FAT, HAMMER and ISO 9660. |
| 10. | The non-native APIs are not supported by its subsystems. | The non-native APIs supported by its subsystems are Mono, Java, Win16, Win32 and Linux. |