Editing OS/2 (section)

====OS/2 2.0 (1992){{anchor|2.0}}====
[[Image:Os2-2.0-wps.png|right|thumb|OS/2 2.0 was the first 32-bit release of OS/2, and the first to feature the Workplace Shell.]]

OS/2 2.0 was released in April 1992. At the time, the suggested retail price was {{US$|195}}, while Windows retailed for {{US$|long=no|150}}.<ref name="Baltimore_Sun">{{cite news |last=Corr |first=O. Casey |title=GIANT-KILLER? Microsoft mounts challenge to IBM |format=Not available in the EU; check the archive URL instead |newspaper=The Baltimore Sun |date=1992-04-06 |url= https://www.baltimoresun.com/news/bs-xpm-1992-04-06-1992097044-story.html |archive-url= https://web.archive.org/web/20200305171806/https://www.baltimoresun.com/news/bs-xpm-1992-04-06-1992097044-story.html |archive-date=2020-03-05}}</ref>

OS/2 2.0 provided a 32-bit API for native programs, though the OS itself still contained some 16-bit code and drivers. It also included a new OOUI (object-oriented user interface) called the [[Workplace Shell]]. This was a fully object-oriented interface that was a significant departure from the previous GUI. Rather than merely providing an environment for program windows (such as the Program Manager), the Workplace Shell provided an environment in which the user could manage programs, files and devices by manipulating objects on the screen. With the Workplace Shell, everything in the system is an "object" to be manipulated.

OS/2 2.0 was touted by IBM as "a better DOS than DOS and a better Windows than Windows".<ref>{{cite news |title=Killer Apps: For Apple's Windows Strategy to Work, It Must Replace Microsoft Office and Buy Adobe Systems |author=Robert X. Cringely |work=pbs.org |date=27 April 2006 |url= https://www.pbs.org/cringely/pulpit/2006/pulpit_20060427_000894.html}}</ref> It managed this by including the fully-licensed MS-DOS 5.0, which had been patched and improved upon. For the first time, OS/2 was able to run more than one DOS application at a time. This was so effective that it allowed OS/2 to run a modified copy of Windows 3.0, itself a [[DOS extender]], including Windows 3.0 applications.

Because of the limitations of the [[Intel 80286]] processor, OS/2 1.x could run only one DOS program at a time, and did this in a way that allowed the DOS program to have total control over the computer. A problem in DOS mode could crash the entire computer. In contrast, OS/2 2.0 could leverage the [[virtual 8086 mode]] of the [[Intel 80386]] processor to create a much safer [[virtual machine]] in which to run DOS programs. This included an extensive set of configuration options to optimize the performance and capabilities given to each DOS program. Any real-mode operating system (such as 8086 [[Xenix]]) could also be made to run using OS/2's virtual machine capabilities, subject to certain direct hardware access limitations.

[[Image:OS2 2.0 upgrade box.png|right|thumb|The OS/2 2.0 upgrade box]]

Like most 32-bit environments, OS/2 could not run protected-mode DOS programs using the older [[VCPI]] interface, unlike the Standard mode of Windows 3.1; it only supported programs written according to [[DOS Protected Mode Interface|DPMI]]. (Microsoft discouraged the use of VCPI under Windows 3.1, however, due to performance degradation.)<ref>{{cite web|title=Windows 3.1 Standard Mode and the VCPI |author=Microsoft |work=support.microsoft.com |date=6 November 1999 |url=http://support.microsoft.com/kb/82298 |url-status=dead |archive-url=https://web.archive.org/web/20130309020041/http://support.microsoft.com/kb/82298 |archive-date=March 9, 2013 }}</ref>

Unlike Windows NT, OS/2 always allowed DOS programs the possibility of masking real hardware interrupts, so any DOS program could [[deadlock (computer science)|deadlock]] the machine in this way. OS/2 could, however, use a hardware [[non-maskable interrupt|watchdog]] on selected machines (notably IBM machines) to break out of such a deadlock. Later, release 3.0 leveraged the enhancements of newer [[i486|Intel 80486]] and [[Pentium (original)|Intel Pentium]] processors&mdash;the [[Virtual Interrupt Flag]] (VIF), which was part of the [[Virtual Mode Extensions]] (VME)&mdash;to solve this problem.

To accommodate those who wanted to have multiple operating systems on their machine, Boot Manager was introduced that allowed for the creation of separate partitions on the boot drive which could be used to install different versions of DOS, Windows and OS/2 and give the user a choice of which partition to boot from.<ref>{{Cite web |date=2014-08-05 |title=Using OS/2 Boot Manager to install multiple operating systems on a single hard file - IBM PC/IBM IntelliStation |url=https://www.ibm.com/support/pages/using-os2-boot-manager-install-multiple-operating-systems-single-hard-file-ibm-pcibm-intellistation |access-date=2025-05-05 |website=www.ibm.com |language=en}}</ref>
{{Further|VME (CONFIG.SYS directive)}}