You are getting cause and effect backwards. > 286 protected mode wasn't the issue... Yes, it was. I evaluated OS/2 1.0 professionally, when it was new; did yo

You are getting cause and effect backwards. > 286 protected mode wasn't the issue... Yes, it was. I evaluated OS/2 1.0 professionally, when it was new; did you? The 286 protected mode was an issue, because it meant that OS/2 could not multitask dos applications — exactly as Concurrent DOS could not on the shipping 286 hardware. > Windows 3.0 was also largely built around 286 protected mode Not really, no. 1. Windows 2 had an edition built around 286 protected mode. This was nothing new for Windows 3.0. The problem is that the 286's protected mode didn't deliver anything that was very useful for dos applications, and in the 1980s, DOS applications were the sole driving factor behind the PC industry. In fact, Windows/286 actually delivered one main benefit: you got an extra 64 kB of RAM. That was it. It wasn't really worth having. Windows 2 also had a 386 edition, generally known as Windows/386. That delivered the core functionality that was the useful thing in the 386 in the 1980s: hardware assisted multitasking of DOS applications. 2. You cite Windows 3.0, but that's not relevant to a discussion of OS/2 1.X, because Windows 3.0 is what happened as a result of OS/2 1.X. OS/2 1.x was a 1980s product. Windows 3.0 came out in 1990, a few months after OS/2 1.2. Windows 3.0 happened in response to the failure of OS/2 1.X, and OS/2 1.X failed because it ran on the 286 processor, when it should've run on the 386 processor — as Microsoft wanted. Windows 2 was able to multitask dos applications, in software, but the problem with doing it that way is that they all had to fit into 640 kB of RAM. And by the late 1980s, a single DOS application barely fit into 640 kB! Windows 3.x was able to multitask DOS applications as well, and it could do it on 8086, on 286, and on 386. The difference is that on a 386, each DOS application got it own 640 kB. So if you had 4 MB of RAM, you could multitask a whole bunch of them. And it sold because the single same edition ran on all three processors, so you didn't have to choose which one you needed in advance, and buy the right product. The one product did it all. And if you upgraded the hardware, you got the additional facilities, with that same copy of the software. (Remember, no product activation in those days!)