Sure--and OS X is the 10th version of that system. ;) I'm thinking that there's probably some confusion over the labeling with this PDP-11 thingie, whatever it is. There would be no good reason to produce an -11 version of OS/2 at the time as the platform was obsolete (or at least obsolescent). My guess is that's someone's OS, but not IBM nor M$. I used DOS on an S/360, but it doesn't resemble anything called "DOS" nowadays (there was also an S/360 TOS; Sytos called their product for the PC a "Tape Operating System", which I found to be very confusing, as it required DOS to run). I do recall (more vividly than I care to, as it still makes my blood boil) one aspect of the OS/2-NT charade. Microsoft solicited and accepted pre-release subscriptions (about $3K each) from OS/2 developers for the "new" OS/2 that was going to be released Real Soon Now. After they had everyone's money, M$ turned around and said that they weren't going to do OS/2, but rather Something Better and that they would be supplying that instead (NT 3.1). IIRC, they nearly had a lynch mob headed toward Redmond screaming for BillG's corpse. M$ did relent and refunded the advance payment to those who screamed loudest. Doubtless, quite a number of people got stuck with a dog of an operating system that they didn't ask for an didn't want. I don't think NT really caught on until about 3.51. One thing that I had to hand IBM was that their developer's documentation was superb for OS/2. The same could not be said for Windows 3.0. I still have both on my bookshelf. In those pre-CD days, you could estimate the quality of the documentation simply by putting the boxes of developer's material on the bathroom scale. I don't know about Vista, but 2K and XP still host the OS/2 subsystem as well as HPFS. I've got a couple of 16-bit OS/2 applications that I still use on 2K. Cheers, Chuck