OS/2 in the context of Microsoft Word

The Personal System/2 or PS/2 is IBM's second generation of personal computers. Released in 1987, it officially replaced the IBM PC, XT, AT, and PC Convertible in IBM's lineup. Many of the PS/2's innovations, such as the 16550 UART (serial port), 1440 KB 3.5-inch floppy disk format, 72-pin SIMMs, PS/2 mouse and keyboard port, and video graphics array, went on to become standards in the broader IBM PC compatibles market.

The PS/2 line was created by IBM partly in an attempt to recapture control of the PC market by introducing the advanced yet proprietary Micro Channel architecture (MCA) on higher-end models. These models were in the strange position of being incompatible with the hardware standards previously established by IBM and adopted in the IBM PC compatible industry. Most major PC manufacturers balked at IBM's licensing terms for MCA-compatible hardware, particularly the per-machine royalties. The OS/2 operating system was announced at the same time as the PS/2 line and was intended to be the primary operating system for models with Intel 80286 or later processors. However, at the time of the first shipments, only IBM PC DOS 3.3 was available. OS/2 1.0 (text-mode only) and Microsoft's Windows 2.0 became available several months later. IBM also released AIX PS/2, a UNIX operating system for PS/2 models with Intel 386 or later processors.

Dominant design is a technology management concept introduced by James M. Utterback and William J. Abernathy in 1975, identifying key technological features that become a de facto standard. A dominant design is the one that wins the allegiance of the marketplace, the one to which competitors and innovators must adhere if they hope to command significant market following.

When a new technology emerges (e.g. computer GUI operating systems) – often firms will introduce a number of alternative designs (e.g. Microsoft – Windows, Apple Inc. – Mac OS and IBM – OS/2). Updated designs will be released incorporating incremental improvements. At some point, an architecture that becomes accepted as the industry standard may emerge, such as Microsoft Windows. The dominant design has the effect of enforcing or encouraging standardization so that production or other complementary economies can be sought. Utterback and Suarez (1993) argue that the competitive effects of economies of scale only become important after the emergence of a dominant design, when competition begins to take place on the basis of cost and scale in addition to product features and performance.

Code page 866 (CCSID 866) (CP 866, "DOS Cyrillic Russian") is a code page used under DOS and OS/2 in Russia to write Cyrillic script. It is based on the "alternative code page" (Russian: Альтернативная кодировка) developed in 1984 in IHNA AS USSR and published in 1986 by a research group at the Academy of Science of the USSR. The code page was widely used during the DOS era because it preserves all of the pseudographic symbols of code page 437 (unlike the "Main code page" or Code page 855) and maintains alphabetic order (although non-contiguously) of Cyrillic letters (unlike KOI8-R). Initially this encoding was only available in the Russian version of MS-DOS 4.01 (1990), but with MS-DOS 6.22 it became available in any language version.

The WHATWG Encoding Standard, which specifies the character encodings permitted in HTML5 which compliant browsers must support, includes Code page 866. It is the only single-byte encoding listed which is not named as an ISO 8859 part, Mac OS specific encoding, Microsoft Windows specific encoding (Windows-874 or Windows-125x) or KOI-8 variant. Authors of new pages and the designers of new protocols are instructed to use UTF-8 instead.