Red spine included just the OS/2 Warp without Window 3.1 (although you can add it with a copy of Windows 3.1.) The Blue spine came with Windows 3.1.
OS/2 Warp 3.0
![](<480:https://os-2.in/wp-content/uploads/2023/12/th-3655250102-150x150.jpg, <768:https://os-2.in/wp-content/uploads/2023/12/th-3655250102-300x225.jpg, >768:https://os-2.in/wp-content/uploads/2023/12/th-3655250102.jpg)
Red spine included just the OS/2 Warp without Window 3.1 (although you can add it with a copy of Windows 3.1.) The Blue spine came with Windows 3.1.
The first client based user operating system to include SMP support.