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. OpenBSD：
OpenBSD是由The OpenBSD Project提供的，专注于安全性，免费和开源的操作系统。它基于Berkeley软件发行版。它是一个类似Unix的操作系统。它可用于许多平台，包括服务器，NAS，工作站和嵌入式系统。它基本上是使用C语言，汇编语言，Perl和Unix Shell编写的。 OpenBSD的第一个版本于1995年发布。此操作系统中使用的内核是单片的。
iOS和OpenBSD之间的区别：
| S.No. | IOS | OPENBSD |
|---|---|---|
| 1. | It was developed and is owned by Apple Incorporation. | It was developed and is owned by The OpenBSD Project. |
| 2. | It was launched in 2007. | It was launched in 1995. |
| 3. | Its target system types are smartphone, music player and tablet computer. | Its target system types are server, NAS, workstation 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 OpenBSD are IA-32, x86-64, SPARC, 68k, Alpha and VAX. |
| 5. | Its kernel types is Hybrid. | Its kernel type is Monolithic with modules. |
| 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 ISC. |
| 8. | Its update management is Software Update. | Its update management is by source or network binary update. |
| 9. | File systems supported by iOS are HFS+ and APFS. | File systems supported by OpenBSD are ffs, ext2, FAT, ISO 9660 and NFS. |
| 10. | It does not have package management. | Its package management is Ports collection/packages. |