OS/2

OS/2 was an operating system originally developed jointly by Microsoft and IBM. Between the release of Windows 3.0 and OS/2 1.3, Microsoft stopped all cooperation with IBM and IBM developed OS/2 on its own, starting with IBM OS/2 2.0 and Microsoft uses OS/2 3.x (not the Warp 3) code to make Windows NT 3.1. OS/2 code was later used to Serenity Systems to work in eComStation and ArcaOS.

History
It begins in 1981, with the launch of the IBM PC 5150 while it wasn't the first personal computer by any means, its usage became so widespread that he term "PC" became synonymous with IBM computers. Or to be more precise, the term described computers that were compatible with IBM's, which meant using x86 architecture and the MS-DOS operating system. Now, IBM had their own version of DOS called "PC-DOS" as well, but it was really just a re-branded version of MS-DOS and didn't become an IBM-developed thing until 1993. And years before that ever came to fruition, there was OS/2.

Development
Its first signs of life came about in August of 1985, when corporate pals IBM and Microsoft signed a joint developement agreement together. The goal was to develop system software based on MS-DOS, but to come up with something far more advanced and future proof. Computer hardware was evolving rapidly at the time and processors like the Intel 286 were all the rage, especially at IBM. But the IBM PC's CP/M-inspired operating system was slowly coming apart at the seams, limiting what could be done with the higher amount of RAM and CPU speed available. IBM had already experimented with addressing some of these issues with their TopView product, Microsoft had their own project with Windows 1.0, and soon to be 2.0, and even CP/M creator Digital Research got in on the action with Concurrent DOS. But something totally new was required to become the true heir to the DOS throne. The result of this joint development agreement was "CP/DOS", which stood for "Control Program Disk Operating System", although this changed to OS/2 for its launch in April of 1987. The reason for the name change was IBM's shiny new PS/2 computer lineup, the next generation of computers meant to completely re-imagine the PC. So, "Personal System/2" launched with "Operating System 2", a net-gen OS for the next-gen PC. However, there were major problems from the start.

Marketing
OS/2 may have had fancy multitasking, virtual memory support, and an API for controlling video, keyboard and mouse input. But because all the software on the market was for DOS, it still had to support it in order to gain any kind of foothold, and this led to some less-than-perfect implementation. OS2 was also lacking any king of graphical user interface until a year later( in OS/2 version 1.1), which kept it looking an awful lot like DOS to your common consumer. Combine this with the disappointing reception of IBM's PS/2 lineup, and the hardware requirements to run it being quite high for its time, and OS/2 had a bit of a shaky start indeed.

Growth
Nonetheless, work on it continued throughout the '80s with each version notably improving its look, feel, and capabilities even Bill Gates said, "I believe OS/2 is destined to be the most important operating system, and possibly program, of all time". Interesting, seeing as Microsoft just happened to be continued to develop Windows while still being funded by IBM to develop OS/2. While the first couple Windows releases were pretty lame, Windows 3.0 in 1990 was another story. Not only were OS/2 and Windows incompatible with each other, but the two companies also had hugely different making strategies. In the OS/2 camp, you had an expensive piece of stand-alone software, which was marketed to promote IBM's computers.But at Microsoft, they continued their dealing with clone manufacturers, and bundled Windows alongside DOS in these machines. Sure, OS/2 could work on these clones as well, but why would you bother when it was more expensive and may not even include the drivers to support your hardware out of the box? This led to Windows and MS-DOS continuing to dominate the OS marketplace and Microsoft parting ways with IBM in 1990.

Decadence
Intriguingly, Microsoft continued to work on the code they had been developing for OS/2 version 3.0(not OS/2 Warp 3), and this eventually became the venerable Windows NT 3.1 in 1993. Yet another slap in the face to IBM. But despite the uphill battle with Windows, OS/2 soldiered on, proving to be a serious force to be reckoned with in OS/2 2.0 and Warp 3. IBM started referring to it as, "A better DOS than DOS, a better Windows than Windows". Since it could run multiple DOS programs at once, and even featured Windows compatibility. In fact, some editions included a nearly complete version of Windows and DOS which gave costumers the best of all parties without having to buy anything extra. Even still, it never really found a foothold in the costumer market, due to Microsoft Windows dominating market share and OS/2 being a costly add-on, instead of a bundled package. By the time 1993 was ending, with Windows 95 on the horizon, it was basically the death knell for OS/2, and it continued to decrease in usage year over that. Though it lasted longer than you might think, with the official final release being OS/2 Warp 4.52 in 2001.

After-Discontinuation
The reason for this was because OS/2 was actually a decent success in the world of specialized hardware. Due to the difficulty in running a virtualized instance of OS/2, many companies have simply held onto it instead of upgrading decades, worth of data. In fact, EComStation was born out of this need for OS/2-compatibility in the modern day and there are still gathering of OS/2 users at annual conferences like WarpStock, keeping the dream alive. So while OS/2 may not have changed the PC market like IBM hoped, it found its niche, which continues to this day. In a sense OS/2 never really died. It just sort of languished in purgatory for years, and now wanders around as a zombie, being kept alive by various user groups and the occasional ATM. It may have been innovation and powerful, but compared to its competitors, it was expensive and lacked the required marketing. Beyond its shaky start, there really wasn't much inherently wrong with OS/2. But its downfall really was death by a thousand cuts, combined with ruthless competition. But, OS/2 is just another footnote in the battle between giants for how we use our computers.

Warp era

 * OS/2 Warp 5
 * Version 5.0
 * Codename Gandalf or Merlin 2
 * Developed 2003, scheduled for release in 2005?
 * Development started but project was later scrapped

Needs to be completed.