OS/2

OS/2 started as a collabrative effort between IBM and Microsoft to put together the next generation Operating System for the IBM AT and PS/2 machines.

Microsoft, famous for hedging bets, started the Windows project around the same time, as a low cost entry interface with rudementary (cooperative) multitasking

Needless to say Microsoft wanted to target the 386 processor, and work on 32bit software, while IBM wanted to deliver to the IBM AT customers it had sold to, and demanded the 286 16bit version. Someone at IBM even got the idea that the development tools should be a revenue stream, and needless to say, the $3,000 SDK was *NOT* a big seller. Instead the industry worked around OS/2, and developed DOS Extenders technology, and Microsoft practically gave away the Windows SDK, allowed for OEM customizations, and famously released the QuickC for Windows product.

Microsoft, lept at the chance to formalize DOS extenders into DPMI, and use it in Windows, cementing OS/2's 1.x inability to run DPMI programs. Microsoft was also upset that IBM locked them out of the graphical components of the OS, and that OS/2 worked BACKWARDS compared to Windows... the 0/0 in the screen coordinates is the bottom right, while everywhere else it's the top left..

There is a great writeup on the divorce on google's usenet archive:

http://groups.google.com/group/comp.os.ms-windows.misc/msg/d710490b745d5e5e Or locally here Gordon Letwin OS/2 usenet post.

Versions

• 1.0

This version was all textmode, and had an interface that was inspired from TopView. Although it could multitask, most people didn't realize it, as all programs ran full screen. It ran in 286 protected mode, except for the single "DOS" mode session. As a result all device drivers for OS/2 had to be able to run in real & protected mode.

• 1.1

This version introduced Presentation Manager. It 'looked' identical to that of Windows 2.0.

• 1.2

This release was signifigant with the inclusion of the HPFS filesystem. HPFS was signifigantly faster then the aging FAT filesystem as it placed it's tables in the middle of the disk, and it allowed for larger filesystems, long filenames and extended attributes.

• 1.3

This was the last version of the 16 bit OS/2 family. A later service pack allowed for 386 and above CPU's to use the 386 method of switching between real & protected mode, allowing it to operate signifigantly faster. Microsoft did include a 32bit HPFS driver in their Lan Manager package which allowed for the fastest HPFS implementation prior to OS/2 2.0 & Windows NT 3.1

The 1.3 user interface resembled that of Windows 3.0.

Around this time, Microsoft had released a beta of the WLO or Windows library for OS/2. The beta included a copy of all of the applettes & games from Windows 3.0 that could run in the Presentation Manager of OS/2. These libraries were also used to deliver the last versions of Microsoft Word & Excel for OS/2. Microsoft had planned on releasing these libraries to allow people to easily port their Windows applications to OS/2, but the rift had happened right before that date, so the beta (which is easy to find) was the only thing released. You can read more about it here.

• 2.0

This was the first 32bit version. It was released after the IBM/Microsoft divorce, and was strictly an IBM release. This release included Windows 3.0 for use in Win OS/2. At the time of the release the Presentation Managers graphic drivers were still 16 bit, although a later service pack was released which included 32bit drivers. It's interesting to note that OS/2's market share was so low at this time, that OS/2 2.0 included the ability to load older 16bit device drivers as the kernel was still a hybrid 16bit/32bit kernel.

The GUI had radically changed from 1.3 to 2.0 as it now included the Workplace Shell, a full OO GUI. Many people considered WPS to be 'the' killer application at the time, as Windows still had the program manager.

• 2.1

This release brought the Win OS/2 functionality up to Windows 3.1. From the user standpoint it still looked like 2.0

• 2.11
• 2.11 SMP

• 3.0

This was the WARP release. At the time this release preempted the Windows 95 release. IBM had done their best to tune OS/2 to run in 4mb of ram on a 386sx cpu. Warp also included the 'bonus pack' which included SLIP/PPP TCP/IP, a dialer application and a word processor & spreadsheet. A simple gopher client & NNTP client were also included.

IMHO this is where IBM missed the boat, by making TCP/IP difficult to configure, and by not including LAN drivers (that was WARP CONNECT), while Windows 95 & NT 3.5 both included SLIP/PPP *AND* lan drivers.

• 4.0

OS/2 4.0 included both Java and Netscape in this release. Sadly IBM had still not 'gotten it' with regards to TCP/IP and insisted on a 'connect' version of 4.0 that included the LAN drivers. 4.0 also included the ability to install servicepacks online.

• 4.5

This was the last IBM release of OS/2.

PowerPC port

It's a deep secret that the PowerPC version ended up sucking up so much time, effort and money from IBM's development of OS/2, that it ended up bleeding the group dry, and without a product to ship. IMHO it's a shame, as partnered with the PowerPC 615 CPU it could have revelutionalized the industry.. But then back then everyone expected Intel to hit a wall, IBM had the 615 in their pocket which was a PowerPC CPU which was pin compatable with a 486, and could run x86 code (albeit slow..) and then switch to PPC mode. The company NexGen opened up everyones eyes that a specialized RISC cpu could infact run x86 instructions much quicker then a real Intel cpu... This opened the way to the Pentium CPU's and effectivly killed the RISC revolution.

Running OS/2 under an Emulator

16 bit versions

OS/2 1.3 under Virtual PC.

The only version of OS/2 1.x that can run under an emulator is 1.3 with all the updates applied. The three problems that you will run into is emulated floppy disks are too quick, and other various timing anonmolaies that will lead to a COUNTRY.SYS failure. The last major hurdle is the method of switching from protected mode to real mode. Prior to the last fixpack for OS/2 1.3 the method was a tripple fault. None of the emulators can accuratly reproduce a tripple fault. However with the fixpack, it will use the 386's normal method for switching between modes.

The method for install requires you to install OS/2 1.3 on a physical machine, update it, then make a whole disk image of it. I can confirm that OS/2 1.3 runs under Virtual PC 2007 just fine.

• Virtual PC 2007

32 bit versions

OS/2 2.0 running under Qemu.

I've run OS/2 2.0 & 4.0 under Virtual PC, and Qemu... I guess it really comes down to if you move disk images around between various hardware platforms. Anything prior to version 3.0 should be run in an ISA emulation mode (-M isa) to let the periphials work in a more compatable manner... Virtual PC 2007 works fine as well, and includes extensions that allow the guest VM to use drives that are installed on the host pc. I've heard that VMWare has given up the compatability mode fixes.

• Qemu
• Virtual PC 2007