OS/2 1.x 1.2

OS/2 was originally a joint effort between IBM and Microsoft. It grew out of efforts to create a Multitasking MS-DOS. It was intended to be the future OS for IBM's new PS/2 series. At release it competed against Microsoft's Windows GUI shell, but most users continued to use DOS. OS/2 1.x was used as the basis for Citrix Multiuser

1.x was heavily criticized for its poor backwards compatibility, heavier system requirements, design decisions made in order to support 286s instead of just 386s, poor hardware compatiblity, and lack of third party driver support. There was an inaccurate, but justifiable, common belief that OS/2 could only run on genuine IBM hardware.

Still, it was believed that all future software development would be for OS/2, until an almost overnight fallout between IBM and Microsoft shifted the spotlight to the yet to be developed Windows NT.

Without Microsoft's help, IBM massively re-wrote OS/2 to produce OS/2 2.x


Installation instructions

To install on a faster computer or VirtualBox, you must first apply the OS/2 speed patches described here to the boot disk: http://www.os2museum.com/wp/installing-os2-1-x-in-a-virtualbox-vm/

To summarize, replace all occurrences of: B8 F4 01 BB C8 00 F7 E3 F7 F1 with B8 F4 01 BB C8 00 F7 E3 90 90

You may also need to partition the disk in advance.

Product type
IBM / Microsoft
Release date
Minimum CPU
Minimum RAM
User interface
Download count
24 (0 for release)


Download name Version Language Architecture File size Downloads
IBM OS/2 1.20 Extended Edition (3.5-1.44mb) 1.20 Extended Edition English 16.6MB 0
IBM OS/2 1.20 Standard Edition (3.5-1.44mb) 1.20 Standard Edition English 7.01MB 0
IBM OS/2 1.20 Standard Edition Manuals 1.20 Standard Edition English 42.03MB 0
Microsoft OS/2 1.21 (3.5-1.44mb) 1.21 English 5.53MB 0
Microsoft OS/2 1.21 (5.25-1.2mb) 1.21 English 5.49MB 0
Microsoft OS/2 1.21 [HP OEM] [German] (3.5-1.44mb) 1.21 [HP OEM] German 5.16MB 0


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