The Windows NT flavour of Microsoft Windows has had the built-in ability, without needing third-party add-on "boot managers", to dual boot with other (Microsoft) operating systems since at least version 4. I can find questions here on SuperUser dealing with dual-booting Windows NT 4 and Windows 2000 (a.k.a. Windows NT 5) with other operating systems, such as:
And there are Microsoft Knowledgebase articles dealing with this:
- How to Triple Boot to Windows NT, Windows 95/98, and MS-DOS
- How to Dual Boot Windows 98 and Windows NT 4.0 with FAT16 or NTFS Volumes
But what about versions before version 4? Could Windows NT 3.51, 3.5, or 3.1 dual boot with other (Microsoft) operating systems, with no third-party tools, too?