1. Linux：
Linux 是一组开源的类 Unix 操作系统，由 Linus Torvalds 开发。它是一个打包的 Linux 发行版。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。 Linux 的第一个版本于 1991 年推出。
2. OpenVMS：
OpenVMS是由美国数字设备公司(DEC)开发的多用户多处理操作系统。它是一种基于虚拟内存的操作系统，设计用于分时、批处理和事务处理。它可用于许多平台，包括服务器和工作站。它是使用 BLISS、VAX Macro、C、Ada、PL/I、Fortran、UIL、Pascal、SDL、C++ 和 DCL 编写的。 OpenVMS 的第一个版本于 1977 年推出。该操作系统中使用的内核是带有模块的单体。
Linux 和 OpenVMS 的区别：
| S.No. | LINUX | OPENVMS |
|---|---|---|
| 1. | It was developed by Linus Torvalds. | It was developed by Digital Equipment Corporation (DEC). |
| 2. | It was launched in 1991. | It was launched in 1977. |
| 3. | Its target system types are embedded systems, mobile devices, personal computers, servers, mainframe computers and supercomputers. | Its target system types are server and workstation. |
| 4. | Computer architectures supported by Linux are IA-32, x86-64, ARM, PowerPC and SPARC. | Computer architectures supported by OpenVMS are VAX, Alpha and IA-64. |
| 5. | Its kernel type is Monolithic. | Its kernel type is Monolithic with modules. |
| 6. | Its native APIs are LINUX/POSIX. | Its native APIs are Proprietary. |
| 7. | It has the preferred license of GNU GPLv2 (kernel). | It has the preferred license of Proprietary. |
| 8. | The non-native APIs supported through its subsystems are Mono, Java, Win16 and Win32. | The non-native APIs supported through its subsystems are POSIX. |
| 9. | Its package management depends on the distribution. | Its package management is PCSI or VMSINSTAL. |
| 10. | It has default GUI ‘on’. | It does not have default GUI ‘on’. |
| 11. | File systems supported by Linux are ext2, ext3, ext4, btrfs, ReiserFS, FAT, ISO 9660, UDF and NFS. | File systems supported by OpenVMS are Files-11, ISO 9660, NFS and CIFS. |