1.iOS：
iOS 是由 Apple Incorporation 提供的移动操作系统。它主要是为 iPhone 和 iPod Touch 等苹果移动设备设计的。它早先被称为 iPhone 操作系统。它是一个基于Darwin(BSD) 操作系统的类Unix 操作系统。它是仅次于 Android 的全球第二大移动操作系统。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 年推出。
2. OpenBSD：
OpenBSD 是由 OpenBSD 项目提供的一个专注于安全的免费开源操作系统。它基于 Berkeley Software Distribution。它是一个类Unix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 年推出。这个操作系统中使用的内核是单片的。
iOS 和 OpenBSD 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. |