On Sun, 14 Mar 2021 at 19:37, Guy Sotomayor via cctalk <cctalk@classiccmp.org> wrote:
> There were many heated discussions in various task forces (this was of > course IBM) about the next generation OS (to become OS/2) about the > '286. First and foremost was how to be able to run DOS programs on the > '286. Over very vocal opposition, management decided to use "mode > switching" rather than any of the other techniques. It should be noted, > that a significant portion of us advocated abandoning the '286 in favor > of the '386 to solve this problem. The argument that management made > against that approach assumed that OS/2 would be ready in 9 months and > that the '386 would be late ('386 at the time was about 12-18 months > away). It turned out that OS/2 took well over 18 months to develop. I will say this, Guy, your posts never cease to amaze me and provide valuable insight! I was on the sidelines at the time -- at university, reading about this stuff in the UK computer mags. From outside too it was very obvious that OS/2 should target the 386. When I started work, I was in tech support in an IBM value-added reseller -- that's where I learned about IBMCACHE.SYS, which we talked of a few years back -- and I can confirm that most PS/2 owners were not at all interested in OS/2. A handful ran 3Com 3+Share or Netware 2 on PS/2 boxes as the server, but most 286 PS/2s were workstations. Only the 386 Model 80 sold almost exclusively as servers. I still have one myself. > At the time I was fairly familiar with the LOADALL instruction. I had > modified PC/AT Xenix to use the LOADALL instruction to allow for running > Xenix programs and multiple DOS programs simultaneously. I gave > multiple demos to various folks in management but to no avail. They had > decided that mode switching as *the* way that OS/2 was going to work. :'( > I should also note, that the other way to get back to real mode from > protected mode is via a triple-fault. What gets me (and I railed on > Intel when I worked there for a time) that it still existing in the > architecture even though they have a machine check architecture now > (which while at IBM pushed Intel to implement for the '386!). (!) -- Liam Proven – Profile: https://about.me/liamproven Email: lpro...@cix.co.uk – gMail/gTalk/gHangouts: lpro...@gmail.com Twitter/Facebook/LinkedIn/Flickr: lproven – Skype: liamproven UK: +44 7939-087884 – ČR (+ WhatsApp/Telegram/Signal): +420 702 829 053