====== MS-DOS (DOS) ======

**MS-DOS** (/ˌɛmˌɛsˈdɒs/ em-es-DOSS; acronym for [[Microsoft]] **Disk Operating System**, also known as **Microsoft DOS**) is an [[operating system]] for [[x86]]-based personal computers mostly developed by [[Microsoft]]. Collectively, **MS-DOS**, its rebranding as **IBM PC DOS**, and a few operating systems attempting to be compatible with **MS-DOS**, are sometimes referred to as **"DOS"** (which is also the generic acronym for **disk operating system**). **MS-DOS** was the main operating system for [[IBM PC]] compatibles during the **1980s**, from which point it was gradually superseded by operating systems offering a graphical user interface (GUI), in various generations of the graphical [[Microsoft]] [[Windows]] [[operating system]].

[[IBM]] licensed and re-released it in **1981** as **PC DOS 1.0** for use in its PCs. Although **MS-DOS** and **PC DOS** were initially developed in parallel by [[Microsoft]] and [[IBM]], the two products diverged after twelve years, in 1993, with recognizable differences in compatibility, syntax, and capabilities.

Beginning in 1988 with **DR-DOS**, several competing products were released for the [[x86]] platform, and **MS-DOS** went through eight versions, until development ceased in 2000. Initially, **MS-DOS** was targeted at [[Intel 8086]] processors running on computer hardware using [[floppy disks]] to store and access not only the [[operating system]], but application software and user data as well. Progressive version releases delivered support for other [[mass storage]] media in ever greater sizes and formats, along with added feature support for newer processors and rapidly evolving computer architectures. Ultimately, it was the key product in [[Microsoft]]'s development from a programming language company to a diverse software development firm, providing the company with essential revenue and marketing resources. It was also the underlying basic [[operating system]] on which early versions of [[Windows]] ran as a **GUI**.

====== History of MS-DOS ======

**MS-DOS** was a renamed form of **86-DOS** – owned by [[Seattle Computer Products]], written by [[dos:Tim Paterson]]. Development of **86-DOS** took only **six weeks**, as it was basically a **clone** of **Digital Research's** [[dos:cpm|CP/M]] (for [[8080]]/[[Z80]] processors), ported to run on [[8086]] processors and with two notable differences compared to [[dos:cpm|CP/M]]: an improved disk sector buffering logic, and the introduction of [[FAT]]12 instead of the [[dos:cpm|CP/M]] filesystem. This first version was shipped in **August 1980**. [[Microsoft]], which needed an operating system for the [[IBM Personal Computer]], hired [[dos:Tim Paterson]] in **May 1981** and bought **86-DOS 1.10** for **US$75,000** in July of the same year. [[Microsoft]] kept the version number, but renamed it **MS-DOS**. They also licensed **MS-DOS** 1.10/1.14 to [[IBM]], which, in **August 1981**, offered it as **PC DOS 1.0** as one of three operating systems for the **IBM 5150** or the **IBM PC**.

Within a year, [[Microsoft]] licensed **MS-DOS** to over **70** other companies. It was designed to be an **OS** that could run on any **8086-family** computer. Each computer would have its own distinct hardware and its own version of **MS-DOS**, similar to the situation that existed for [[dos:cpm|CP/M]], and with **MS-DOS** emulating the same solution as [[dos:cpm|CP/M]] to adapt for different hardware platforms. To this end, **MS-DOS** was designed with a modular structure with internal device drivers (the [[dos:DOS BIOS]]), minimally for primary disk drives and the console, integrated with the kernel and loaded by the boot loader, and installable device drivers for other devices loaded and integrated at boot time. The **OEM** would use a **development kit** provided by [[Microsoft]] to build a version of **MS-DOS** with their basic **I/O drivers** and a standard [[Microsoft]] **kernel**, which they would typically supply on disk to end users along with the hardware. Thus, there were many different versions of "MS-DOS" for different hardware, and there is a major distinction between an **IBM-compatible** (or ISA) machine and an **MS-DOS** [compatible] machine. Some machines, like the [[Tandy 2000]], were **MS-DOS** compatible but not **IBM-compatible**, so they could run software written exclusively for **MS-DOS** without dependence on the **peripheral hardware** of the **IBM PC architecture**.

This design would have worked well for compatibility, if application programs had only used **MS-DOS** services to perform **device I/O**, and indeed the same design philosophy is embodied in [[windows:Windows NT]] (see [[windows:Hardware Abstraction Layer]]). However, in **MS-DOS's** early days, the greater speed attainable by programs through **direct control of hardware** was of particular importance, especially for **games**, which often pushed the limits of their contemporary hardware. Very soon an **IBM-compatible** architecture became the goal, and before long all **8086-family** computers closely emulated **IBM's hardware**, and only a single version of **MS-DOS** for a fixed hardware platform was needed for the market. This version is the version of **MS-DOS** that is discussed here, as the dozens of other OEM versions of "MS-DOS" were only relevant to the systems they were designed for, and in any case were very similar in function and capability to some standard version for the **IBM PC—often** the same-numbered version, but not always, since some **OEMs** used their own proprietary version numbering schemes (e.g. labeling later releases of **MS-DOS** 1.x as 2.0 or vice versa)—with a few notable exceptions.

[[Microsoft]] omitted multi-user support from **MS-DOS** because [[Microsoft]]'s **Unix-based** operating system, [[Xenix]], was fully multi-user. The company planned, over time, to improve **MS-DOS** so it would be almost indistinguishable from single-user [[Xenix]], or [[XEDOS]], which would also run on the **Motorola 68000**, **Zilog Z8000**, and the **LSI-11**; they would be upwardly compatible with [[Xenix]], which **Byte** in 1983 described as //"the multi-user MS-DOS of the future"//. [[Microsoft]] advertised **MS-DOS** and [[Xenix]] together, listing the shared features of its "single-user OS" and "the multi-user, multi-tasking, UNIX-derived operating system", and promising easy porting between them. After the breakup of the Bell System, however, AT&T Computer Systems started selling UNIX System V. Believing that it could not compete with AT&T in the Unix market, **Microsoft abandoned Xenix**, and in 1987 **transferred ownership** of [[Xenix]] to the [[Santa Cruz Operation]] **(SCO)**.

On March 25, 2014, Microsoft made the code to SCP **MS-DOS 1.25** and a mixture of **Altos MS-DOS 2.11** and **TeleVideo PC DOS 2.11** **available to the public** under the Microsoft Research License Agreement, which makes the code source-available, but not open source as defined by Open Source Initiative or Free Software Foundation standards. Microsoft would later re-license the code under the MIT License on September 28, 2018, making these versions free software.

As an April Fool's Day joke in 2015, Microsoft Mobile launched a Windows Phone application called **MS-DOS Mobile** which was presented as a new mobile operating system and worked similar to MS-DOS.

====== Download MS-DOS ======

  * [[https://github.com/microsoft/MS-DOS|MS-DOS 1.25 and 2.0 original sources]]
  * [[https://winworldpc.com/product/ms-dos/1x|MS-DOS 1.x Disk Images]] **Release date 1981** 
  * [[https://winworldpc.com/product/ms-dos/2x|MS-DOS 2.x Disk Images]] **Release date 1983** 
  * [[https://winworldpc.com/product/ms-dos/30|MS-DOS 3.00 Disk Images]] **Release date 1984** 
  * [[https://winworldpc.com/product/ms-dos/310|MS-DOS 3.10 Disk Images]] **Release date 1984** 
  * [[https://winworldpc.com/product/ms-dos/320|MS-DOS 3.20 Disk Images]] **Release date 1986** 
  * [[https://winworldpc.com/product/ms-dos/321|MS-DOS 3.21 Disk Images]] **Release date 1987** 
  * [[https://winworldpc.com/product/ms-dos/3x|MS-DOS 3.30 Disk Images]] **Release date 1988** 
  * [[https://winworldpc.com/product/ms-dos/331|MS-DOS 3.31 Disk Images]] **Release date 1988** 
  * [[https://winworldpc.com/product/ms-dos/4x|MS-DOS 4.0x Disk Images]] **Release date 1988** 
  * [[https://winworldpc.com/product/ms-dos/50|MS-DOS 5.0 Disk Images]] **Release date 1991** 
  * [[https://winworldpc.com/product/ms-dos/6x|MS-DOS 6.0 Disk Images]] **Release date 1993** 
  * [[https://winworldpc.com/product/ms-dos/620|MS-DOS 6.20 Disk Images]] **Release date 1993** 
  * [[https://winworldpc.com/product/ms-dos/621|MS-DOS 6.21 Disk Images]] **Release date 1994** 
  * [[https://winworldpc.com/product/ms-dos/622|MS-DOS 6.22 Disk Images]] **Release date 1994** 
  * [[https://winworldpc.com/product/ms-dos/7x|MS-DOS 7.1 Disk Images]] **Release date 1996** 

====== Software for MS-DOS ======

  * [[dos:Software]]
  * [[dos:Dos Games Pack|Games]]

====== Connectivity/transfer files to dos machine ======

  * [[dos:dos_pcmcia_drivers|Using PCMCIA CF Card]] and/or MicroSD/SD Card
  * [[dos:serial_wifi_adapter|Serial WIFI Adapter]] a self made device that connects to modern wifi network and another end connects to your PC serial port
  * [[sdlpt|SD LPT Adapter]] ready to buy device that connects to your computer LPT (printer) port and acts as SD Card adapter
  * [[dos:ms-dos_wifi|MS-DOS Compatible WIFI Cards]]
  * [[dos:Ad-hoc connectivity on DOS machines]] A way to transfer data between two vintage computers connected using [[https://en.wikipedia.org/wiki/LapLink_cable|LapLink]] cable.

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