Comparison of DOS operating systems
This article details versions of MS-DOS, IBM PC DOS, and at least partially compatible disk operating systems. It does not include the many other operating systems called "DOS" which are unrelated to IBM PC compatibles.
Historical and licensing information
Originally MS-DOS was designed to be an operating system that could run on any computer with a 8086-family microprocessor. It competed with other operating systems written for such computers, such as CP/M-86 and UCSD Pascal. Each computer would have its own distinct hardware and its own version of MS-DOS, a situation similar to the one that existed for CP/M, with MS-DOS emulating the same solution as CP/M to adapt for different hardware platforms. So there were many different original equipment manufacturer versions of MS-DOS for different hardware. But the greater speed attainable by direct control of hardware was of particular importance, especially when running computer games. So very soon an IBM-compatible architecture became the goal, and before long all 8086-family computers closely emulated IBM hardware, and only a single version of MS-DOS for a fixed hardware platform was all that was needed for the market. This specific version of MS-DOS is the version that is discussed here, as all other versions of MS-DOS died out with their respective systems. One version of such a generic MS-DOS is mentioned here, but there were dozens more. All these were for personal computers that used an 8086-family microprocessor, but which were not fully IBM PC compatible.| Name | First public release date | Creator | Owner or maintainer as of 2021 | License |
| 86-DOS 0.42 | Seattle Computer Products | rowspan="15" | rowspan="16" | |
| 86-DOS 1.00 | Seattle Computer Products | - | - | |
| PC DOS 1.0 | Microsoft | - | - | |
| PC DOS 1.1 | Microsoft | - | - | |
| PC DOS 2.0 | Microsoft | - | - | |
| PC DOS 2.1 | Microsoft | - | - | |
| PC DOS 3.0 | Microsoft | - | - | |
| PC DOS 3.1 | Microsoft | - | - | |
| PC DOS 3.2 | Microsoft | - | - | |
| PC DOS 3.3 | Microsoft | - | - | |
| IBM DOS 4.0 | Microsoft | - | - | |
| IBM DOS 5.0 | Microsoft | - | - | |
| PC DOS 6.1, PC DOS 6.3 | IBM | - | - | |
| PC DOS 7.0 | IBM | - | - | |
| PC DOS 2000 | IBM | - | - | |
| PC DOS 7.10 | IBM | - | ||
| MS-DOS 1.25 | Microsoft | rowspan="16" | , MIT License | |
| Z-DOS 1.25 | OEM Zenith Data Systems | - | ||
| MS-DOS 2.0 | Microsoft | , MIT License | - | |
| MS-DOS 2.11 | Microsoft | rowspan="5" | - | |
| MS-DOS 3.0 | Microsoft | - | - | |
| MS-DOS 3.1 | Microsoft | - | - | |
| MS-DOS 3.2 | Microsoft | - | - | |
| MS-DOS 3.3 | Microsoft | - | - | |
| MS-DOS 4.0 | Microsoft | , MIT License | - | |
| MS-DOS 5.0 | Microsoft | rowspan="15" | - | |
| MS-DOS 6.0 | Microsoft | - | - | |
| MS-DOS 6.20 | Microsoft | - | - | |
| MS-DOS 6.21 | Microsoft | - | - | |
| MS-DOS 6.22 | Microsoft | - | - | |
| MS-DOS 7.0 | Microsoft | - | - | |
| MS-DOS 7.10 | Microsoft | - | - | |
| MS-DOS 8.0 | Microsoft | - | ||
| DOS Plus 1.1, 1.2/1.2a | Digital Research | rowspan="7" | - | |
| DOS Plus 2.1 | Digital Research | - | - | |
| DR DOS 3.31-3.35 | Digital Research | - | - | |
| DR DOS 3.40-3.41 | Digital Research | - | - | |
| DR DOS 5.0 | Digital Research | - | - | |
| DR DOS 6.0 | Digital Research | - | - | |
| Novell DOS 7 | Novell | - | - | |
| Caldera OpenDOS 7.01 | Caldera, Inc.; Caldera UK, Ltd. | officially; a derivative, Enhanced DR-DOS, was maintained by Udo Kuhnt until 2011 | rowspan="2", free non-commercial use | |
| Caldera DR-OpenDOS 7.02 | Caldera, Inc.; Caldera UK, Ltd. | rowspan="2" | - | |
| Caldera DR-DOS 7.02 | Caldera, Inc.; Caldera UK, Ltd. | rowspan="4" | - | |
| Caldera DR-DOS 7.03 | 1999, 1998 prereleased | Caldera Thin Clients, Inc.; Caldera UK, Ltd; Lineo, Inc. | - | |
| DR-DOS 8.0 | DeviceLogics | rowspan="2" | - | |
| DR-DOS 8.1 | DRDOS, Inc. | - | - | |
| FreeDOS 1.0 | Jim Hall, et al. | rowspan="4" | rowspan="4", GPL | |
| FreeDOS 1.1 | Jim Hall, et al. | - | - | |
| FreeDOS 1.2 | Jim Hall, et al. | - | - | |
| FreeDOS 1.3 | Jim Hall, et al. | - | - | |
| PTS-DOS 6.4 | PhysTechSoft | rowspan="5" | rowspan="11" | |
| PTS-DOS 6.5 | ? | PhysTechSoft | - | - |
| PTS-DOS 6.6 | ? | PhysTechSoft | - | - |
| PTS-DOS 2000 | ? | PhysTechSoft | - | - |
| PTS-DOS 32 | ? | PhysTechSoft | - | - |
| PTS-DOS 6.51 | ca. | Paragon Technology Systems | rowspan="2" | - |
| Paragon DOS 2000 Pro | ? | Paragon Technology Systems | - | - |
| ROM-DOS 6.22 | ? | Datalight | rowspan="2" | - |
| ROM-DOS 7.1 | ? | Datalight | - | - |
| Embedded DOS | ? | General Software | - | |
| DIP DOS 2.11 | DIP Research, Atari Corporation | - | ||
| RxDOS 6.2 | Michael Podanoffsky | rowspan="2", GPL | ||
| RxDOS 7.20-7.24 | C. Masloch | - | ||
| SISNE plus | ? | Itautec, Scopus Tecnologia |