IBM Advert - January 1993

OS/2 was an operating system originally intended to replace Microsoft's PC-DOS on IBM's then-latest IBM PC - the PS/2.

Originally intended as a multi-tasking and windowing operating system, it was initially co-developed with Microsoft, with the two companies signing a joint development agreement in April 1987^[1].

However, it was significantly delayed to the extent that its first release had to be text only, with the Presentation Manager part not arriving until the following year.

By the time it was shipping as a full operating system, Microsoft's own Windows 3 had already built up a huge install base, and when OS/2 version 2.0 was released and IBM announced that it had shipped one million copies, Microsoft was noted to be shipping one million copies of Windows every month, largely thanks to Windows being bundled with almost every new PC.

According to Personal Computer World, although OS/2 was accepted as "a suitable platform for bespoke software development", it had been roundly rejected by a significant majority of third-party developers, with only Lotus targetting it as a development platform.

By 1990, the agreement with Microsoft turned sour and the partnership broke up, leaving IBM to continue with development by itself, which it did until its last major release - OS/2 Warp 4 in 1996.

All of which led to Personal Computer World giving OS/2 its "Turkey of the year" award for 1992, quipping:

"The only way for IBM to get a reasonable return on its R&D and marketing investment into OS/2 would be for the company to reformat all the OS/2 disks and sell them off as blanks^[2]".

Much of Microsoft's work on OS/2 version 3.0 - in particular OS/2 LAN Manager - is said to have lived on in what became the release of its first "workstation" operating system, Windows NT.