1. Linux：
Linux是由Linus Torvalds开发的一组类似于Unix的开源操作系统。它是Linux发行版的打包。一些最常用的Linux发行版是Debian，Fedora和Ubuntu。它基本上是用C语言和汇编语言编写的。 Linux中使用的内核是Monolithic内核。 Linux发行版的目标系统是云计算，嵌入式系统，移动设备，个人计算机，服务器，大型计算机和超级计算机。 1991年发布了第一个Linux版本。
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。
Linux和OpenBSD之间的区别：
| S.No. | LINUX | OPENBSD |
|---|---|---|
| 1. | It was developed by Linus Torvalds. | It was developed by The OpenBSD Project. |
| 2. | It was launched in 1991. | It was launched in 1995. |
| 3. | Its target system types are embedded systems, mobile devices, personal computers, servers, mainframe computers and supercomputers. | Its target system types are server, NAS, workstation and embedded systems. |
| 4. | Computer architectures supported by Linux are IA-32, x86-64, ARM, PowerPC and SPARC. | Computer architectures supported by OpenBSD are IA-32, x86-64, SPARC, 68k, Alpha and VAX. |
| 5. | Its kernel type is Monolithic. | Its kernel type is Monolithic with modules. |
| 6. | Its native APIs are LINUX/POSIX. | Its native APIs are BSD-POSIX. |
| 7. | It has preferred license of GNU GPLv2 (kernel). | It has the preferred license of ISC. |
| 8. | Its package management depends on the distribution. | Its package management is Ports collection/packages. |
| 9. | The non-native APIs supported through its subsystems are Mono, Java, Win16 and Win32. | The non-native APIs are not supported through its subsystems. |
| 10. | Its update management depends on the distribution. | Its update management is by source or by binary. |
| 11. | File systems supported by Linux are ext2, ext3, ext4, btrfs, ReiserFS, FAT, ISO 9660, UDF and NFS. | File systems supported by OpenBSD are ffs, ext2, FAT, ISO 9660 and NFS. |