International Business Machines (IBM) Corporation is a major player in the history of the computer development.Its computer related technologies cover hardware, operating systems and applications.In the following table, we listed the main computer operating systems (OS) created (or co-created) by IBM in the past decades for mainframe computer, Mid-range computer, desktop computer and Unix based OS for mid-range and mainframe computers.
| Date | OS | Computer | Notes |
| Early OS | |||
| 1956 | GM-NAA I/O | IBM 704 | |
| 1959 | SOS SHARE OS | Scientific Mainframe Computer | |
| 1967 | ACP Airline | System/360 Airline applications | A special version of OS for airline applications. |
| Mainframe OS Track 1 | |||
| 1960 | IBSYS | IBM 7090 and 7094 | |
| 1964 | OS/360 | System/360 | IBM announced System/360. |
| 1965 | TOS Tape | System/360 | |
| 1966 | DOS/360 | System /360 | |
| 1972 | MFT | System/360, 370 | System/370 announced in 1970. |
| 1972 | VS1 | System/370 | Variant of OS/360 |
| 1972 | MVT | System/370 | Variant of OS/360 |
| 1973 | SVS | System/370 | Renamed from MVT |
| 1974 | VS2 | System/370 | Based on VS1 and MVT |
| 1975 | MVS (Multiple Virtual Storage) | System/370 | Renamed from VS2 r3 |
| 1977 | MVS/SP | System/370 | |
| 1979 | MVS/370 | System/370 | Rename from MVS |
| 1981 | MVS/XA | System/370 | Rename from MVS |
| 1988 | MVS/ESA | System/370 | Rename from MVS |
| 1995 | MVS/ESA SP5R2 | System/370, 390 | IBM announced System/390 to replace System/370. This is the last MVS release. |
| 1996 | OS/390 v1 | System/390 | Rebranded from MVS with added UNIX System Services |
| 1997 | OS/390 v2 | System/390 | Last version of OS/390 is OS/390 v2.10 in 2000. |
| 2001 | z/OS v1 (zSeries/Operating System) | For System/390 and zSeries | In 2000, IBM announced zSeries to replace System/390. z/OS is the successor to OS/390 with 64-bit support. |
| 2007 | z/OS v1.9 | For System/390 and zSeries | Current release |
| Mainframe OS track 2 | |||
| 1966 | CP-40 | For System/360 | Based on MIT CTSS |
| 1968 | CP-67 | For System/360 | |
| 1968 | CP/CMS v1 | For System/360 | |
| 1969 | CP/CMS v2 | For System/360 | |
| 1971 | CP/CMS v3 | For System/360 | |
| 1972 | VM/CMS v1 | For System/370 | A System/370 reimplementation of CP/CMS |
| 1974 | VM/CMS v2 | For System/370 | |
| 1976 | VM/CMS v3 | For System/370 | |
| 1976 | SEPP and BSEPP | For System/370 | Systems Extensions Program Product |
| 1977 | VM/CMS v5 | For System/370 | With the new systems extensions, BSEPP and SEPP. |
| 1979 | VM/CMS v6 | For System/370 | With Release 2 of BSEPP and SEPP |
| 1980 | VM/SP1 | For System/370 | |
| 1981 | VM/XA | For System/370 Extended Architecture | |
| 1981 | VM/HPO | For System/370 | Updates to VM/SP to enhance it to support high-end S/370 processors running in 370 mode. |
| 1982 | VM/SP2 | For System/370 | |
| 1983 | VM/SP3 | For System/370 | |
| 1985 | VM/SP4 | For System/370 | |
| 1985 | VM XA/SF | For System/370 Extended Architecture | |
| 1987 | VM/SPv5 | For System/370 | |
| 1988 | VM/SPv6 | For System/370 | |
| 1989 | VM/IS | For System/370 | |
| 1989 | VM XA/SP1 and 2 | For System/370 Extended Architecture | |
| 1990 | VM/ESA v1 | For System/370, 390 | IBM announced System/390. |
| 1995 | VM/ESA v2 | For System/390 | |
| 2000 | zVM v3 | IBM's zSeries and System z9 computers | IBM announced zSeries. zVM is based on VM/ESA v2 r4. |
| 2001 | zVM v4 | zSeries and System z9 computers | |
| 2004 | zVM v5 | zSeries and System z9 computers | |
| 2007 | zVM v5.3 | zSeries and System z9 computers | The latest version |
| Desktop OS | |||
| 1987 | OS/2 1.0 | IBM PS/2 / Intel 80286 Processor | Joint with Microsoft |
| 1991 | OS/2 1.3 | IBM PS/2 / Intel 80286 Processor | |
| 1992 | OS/2 2.0 | IBM PS/2 / Intel 80386 Processor | |
| 1994 | OS/2 3.0 (or OS/2 Warp) | Support both desktop and server. | Add networking capabilities. Windows NT is based on OS/2 3.0 |
| 1996 | OS/2 4.0 (or OS/2 Warp 4) | Support both desktop and server. | Added Java and speech recognition software |
| 2001 | OS/2 4.52 | Support both desktop and server. | Last IBM release of OS/2; IBM had stopped selling IS/2 by the end of 2005 and stopped support of OS/2 by the end of 2006. |
| Unix Based OS | |||
| 1986 | AIX v1 (Advanced IBM UNIX) | IBM PS/2 Micro Channel architecture PCs and IBM RT. | Based on Unix System V Release 3. |
| 1987 | AIX v2 | For 6150-series IBM RT systems | |
| 1988 | AIX/370 | For the mainframe System/370 | |
| 1990 | AIX v3 | IBM POWER architecture | |
| 1994 | AIX v4 | For PowerPC architecture and PCI bus. | |
| 2001 | AIX v5L | For IA64 architecture and PowerPC 4 & 5, 970 | |
| 2007 | AIX v6 | POWER6, System i5 | Partition mobility on POWER6 |
| Mid-range Computer | |||
| 1988 | OS/400 v1 | AS/400 | |
| 1991 | OS/400 v1 | AS/400 | |
| 1994 | OS/400 v3 | AS/400 | |
| 1997 | OS/400 v4 | AS/400 | |
| 2001 | OS/400 v5 | AS/400 or iSeries Systems | IBM rebranded AS/400 to iSeries. |
| 2005 | OS/400 v5.4 | iSeries Systems | Last release of OS/400 is OS/400 v5.4. |
| 2006 | i5/OS v5r4 | System i | IBM re-branded iSeries to System i. i5/OS is re-branded from OS/400; Co-exist with AIX and Linux. |
| 2008 | i5/OS v6r1 | System i | |