1. Windows：
Windows是Microsoft Incorporation提供的一组各种专有图形操作系统。它也被称为Microsoft Windows 。它目前包括Windows NT和Windows IoT作为其家族的成员。早期包括不再使用的Windows 9x，Windows Mobile和Windows Phone。它是个人计算机中使用最多的操作系统。 Windows的第一个版本由Microsoft于1985年发布。它具有带有模块的混合内核。
2. OS / 2：
OS / 2是由Microsoft Incorporation和IBM协调开发的一系列操作系统。它的目标系统是个人计算机和服务器。它使用C，C++和汇编语言编写。 OS / 2的第一个版本于1987年发布。它于2006年停产，此后以eComStation的名称进行更新，维护和销售。在2015年，它被命名为ArcaOS 。此操作系统中使用的内核是带有模块的Monolithic。
Windows和OS / 2之间的区别：
| S.No. | WINDOWS | OS/2 |
|---|---|---|
| 1. | It was developed by Microsoft Incorporation. | It was developed by co-ordination of Microsoft Inc. and IBM. |
| 2. | It was launched in 1985. | It was launched in 1987. |
| 3. | Its target systems types are workstation, personal computers, media center, tablets and embedded systems. | Its target system types are personal computers and servers. |
| 4. | Computer architectures supported by Windows are IA-32, x86-64, IA-64, ARM, Alpha, MIPS and PowerPC. | Computer architectures supported by OS/2 are 16-bit x86 (1.x only) and IA-32. |
| 5. | Its kernel type is Hybrid with modules. | Its kernel type is Monolithic with modules. |
| 6. | Its native APIs are Win32 and NT API. | Its native APIs are Proprietary, DOS API and Win16. |
| 7. | It has the preferred license Proprietary and Source available. | It has the preferred license of Proprietary. |
| 8. | The non-native APIs supported through its subsystems are DOS API, Win16, POSIX and .NET. | The non-native APIs supported through its subsystems are Win32. |
| 9. | Its package management is MSI or custom installer. | Its package management is Feature Install. |
| 10. | File systems supported by Windows are NTFS, FAT, ISO 9660, UDF, HFS+, FATX and HFS. | File systems supported by OS/2 are HPFS, JFS, FAT, ISO 9660, UDF and NFS. |