FreeDOS (formerly Free-DOS and PD-DOS) is a

free software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, no ...

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

for

IBM PC compatible IBM PC compatible computers are similar to the original IBM PC, XT, and AT, all from computer giant IBM, that are able to use the same software and expansion cards. Such computers were referred to as PC clones, IBM clones or IBM PC clones. ...

computers. It intends to provide a complete

MS-DOS MS-DOS ( ; 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 ope ...

-compatible environment for running

legacy software In computing, a legacy system is an old method, technology, computer system, or application program, "of, relating to, or being a previous or outdated computer system", yet still in use. Often referencing a system as "legacy" means that it paved ...

and supporting

embedded system An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded'' as ...

s. FreeDOS can be booted from a

floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined w ...

USB flash drive A USB flash drive (also called a thumb drive) is a data storage device that includes flash memory with an integrated USB interface. It is typically removable, rewritable and much smaller than an optical disc. Most weigh less than . Since firs ...

. It is designed to run well under

virtualization In computing, virtualization or virtualisation (sometimes abbreviated v12n, a numeronym) is the act of creating a virtual (rather than actual) version of something at the same abstraction level, including virtual computer hardware platforms, stor ...

x86 x86 (also known as 80x86 or the 8086 family) is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel based on the Intel 8086 microprocessor and its 8088 variant. The 8086 was introd ...

emulation Emulation may refer to: *Emulation (computing), imitation of behavior of a computer or other electronic system with the help of another type of system :*Video game console emulator, software which emulates video game consoles *Gaussian process em ...

. Unlike most versions of

, FreeDOS is composed of

licensed A license (or licence) is an official permission or permit to do, use, or own something (as well as the document of that permission or permit). A license is granted by a party (licensor) to another party (licensee) as an element of an agreeme ...

under the terms of the

GNU General Public License The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the Four Freedoms (Free software), four freedoms to run, study, share, and modify the software. The license was th ...

. However, other packages that form part of the FreeDOS project include non-GPL software considered worthy of

preservation Preservation may refer to: Heritage and conservation * Preservation (library and archival science), activities aimed at prolonging the life of a record while making as few changes as possible * ''Preservation'' (magazine), published by the Nat ...

, such as

4DOS 4DOS is a command-line interpreter by JP Software, designed to replace the default command interpreter COMMAND.COM in Microsoft DOS and Windows. It was written by Rex C. Conn and Tom Rawson and first released in 1989. Compared to the default, ...

, which is distributed under a modified

MIT License The MIT License is a permissive free software license originating at the Massachusetts Institute of Technology (MIT) in the late 1980s. As a permissive license, it puts only very limited restriction on reuse and has, therefore, high license comp ...

History

The FreeDOS project began on 29 June 1994, after

Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washing ...

announced it would no longer sell or support MS-DOS. Jim Hall – who at the time was a student – posted a manifesto proposing the development of PD-DOS, a

public domain The public domain (PD) consists of all the creative work A creative work is a manifestation of creative effort including fine artwork (sculpture, paintings, drawing, sketching, performance art), dance, writing (literature), filmmaking, ...

version of DOS. Within a few weeks, other programmers including

Pat Villani Pasquale "Pat" J. Villani (18 April 1954 – 27 August 2011) was an American computer programmer, author, and advocate of free software, best known for his creation of DOS-C, a DOS emulator written in the C language and subsequently adapted as ...

and Tim Norman joined the project. Between them, a kernel (by Villani), the

COMMAND.COM COMMAND.COM is the default command-line interpreter for MS-DOS, Windows 95, Windows 98 and Windows Me. In the case of DOS, it is the default user interface as well. It has an additional role as the usual first program run after boot (init proc ...

command line interpreter (by Villani and Norman), and core utilities (by Hall) were created by pooling code they had written or found available. For some time, the project was maintained by Morgan "Hannibal" Toal. There have been many official pre-release distributions of FreeDOS before the final FreeDOS 1.0 distribution. GNU/DOS, an unofficial distribution of FreeDOS, was discontinued after version 1.0 was released. Blinky the Fish is the mascot of FreeDOS. He was designed by Bas Snabilie.

Distribution

FreeDOS 1.1, released on 2 January 2012, is available for download as a

CD-ROM A CD-ROM (, compact disc read-only memory) is a type of read-only memory consisting of a pre-pressed optical compact disc that contains data. Computers can read—but not write or erase—CD-ROMs. Some CDs, called enhanced CDs, hold both comput ...

image: a limited install disc that only contains the kernel and basic applications, and a full disc that contains many more applications (games, networking, development, etc.), not available but with a newer, fuller 1.2. The legacy version 1.0 (2006) consisted of two CDs, one of which was an 8 MB install CD targeted at regular users and the other which was a larger 49 MB live CD that also held the source code of the project.

Commercial uses

FreeDOS is used by several companies: *

Dell Dell is an American based technology company. It develops, sells, repairs, and supports computers and related products and services. Dell is owned by its parent company, Dell Technologies. Dell sells personal computers (PCs), servers, data ...

preloaded FreeDOS with their n-series desktops to reduce their cost. The firm has been criticized for making these machines no cheaper, and harder to buy, than identical systems with Windows. * HP provided FreeDOS as an option in its dc5750 desktops, ''Mini 5101'' netbooks and ''Probook'' laptops. FreeDOS is also used as bootable media for updating the BIOS firmware in HP systems. * FreeDOS is included by Steve Gibson's hard drive maintenance and recovery program, SpinRite. * Intel's Solid-State Drive Firmware Update Tool loaded the FreeDOS kernel.

Non-commercial uses

FreeDOS is also used in multiple independent projects: * FED-UP is the Floppy Enhanced DivX Universal Player. * FUZOMA is a FreeDOS-based distribution that can boot from a

and converts older computers into educational tools for children. * XFDOS is a FreeDOS-based distribution with a

graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

, porting Nano-X and FLTK.

Compatibility

Hardware

FreeDOS requires a PC/XT machine with at least 640 kB of memory. Programs not bundled with FreeDOS often require additional system resources.

MS-DOS and Win32 console

FreeDOS is mostly compatible with MS-DOS. It supports COM executables, standard DOS executables and Borland's 16-bit DPMI executables. It is also possible to run 32-bit DPMI executables using

DOS extender A DOS extender is a computer software program running under DOS that enables software to run in a protected mode environment even though the host operating system is only capable of operating in real mode. DOS extenders were initially developed ...

s. The operating system has several improvements relative to MS-DOS, mostly involving support for newer standards and technologies that did not exist when Microsoft ended support for MS-DOS, such as internationalization, or the Advanced Power Management TSRs. Furthermore, with the use of HX DOS Extender, many

Windows Console Windows Console is the infrastructure for console applications in Microsoft Windows. An instance of a Windows Console has a screen buffer and an input buffer. It allows console apps to run inside a window or in hardware text mode (so as to oc ...

applications function properly in FreeDOS, as do some rare GUI programs, like

QEMM Quarterdeck Expanded Memory Manager (QEMM) is a memory manager produced by Quarterdeck Office Systems in the late 1980s through the late 1990s. It was the most popular third-party memory manager for the MS-DOS and other DOS operating systems. ...

and

Bochs Bochs (pronounced "box") is a portable IA-32 and x86-64 IBM PC compatible emulator and debugger mostly written in C++ and distributed as free software under the GNU Lesser General Public License. It supports emulation of the processor(s) (includin ...

DOS-based Windows

FreeDOS is able to run

Microsoft Windows 1.0 Windows 1.0 is the first major release of Microsoft Windows, a family of graphical operating systems for personal computers developed by Microsoft. It was first released to manufacturing in the United States on November 20, 1985, while the Eur ...

and 2.0 releases.

Windows 3.x Windows 3.x means either of, or all of the following versions of Microsoft Windows: * Windows 3.0 * Windows 3.1x Windows 3.1 is a major release of Microsoft Windows. It was released to manufacturing on April 6, 1992, as a successor to Windo ...

releases, which had support for

i386 The Intel 386, originally released as 80386 and later renamed i386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistors except partially in the experimental FreeDOS kernel 2037.

Windows 95 Windows 95 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of operating systems. The first operating system in the 9x family, it is the successor to Windows 3.1x, and was released to manufacturin ...

Windows 98 Windows 98 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. The second operating system in the 9x line, it is the successor to Windows 95, and was released to ...

and

Windows Me Windows Millennium Edition, or Windows Me (marketed with the pronunciation of the pronoun "me"), is an operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It is the successor to Windo ...

use a stripped-down version of MS-DOS. FreeDOS cannot be used as a replacement because the undocumented interfaces between MS-DOS 7.0–8.0 and Windows "4.xx" are not emulated by FreeDOS; however, it can be installed and used beside these systems using a boot manager program, such as BOOTMGR or METAKERN included with FreeDOS.

Windows NT and ReactOS

Windows NT-based operating systems, including

Windows 2000 Windows 2000 is a major release of the Windows NT operating system developed by Microsoft and oriented towards businesses. It was the direct successor to Windows NT 4.0, and was Software release life cycle#Release to manufacturing (RTM), releas ...

, XP,

Vista Vista usually refers to a distant view. Vista may also refer to: Software *Windows Vista, the line of Microsoft Windows client operating systems released in 2006 and 2007 *VistA, (Veterans Health Information Systems and Technology Architecture) ...

, 7, 8,

8.1 Windows 8.1 is a release of the Windows NT operating system developed by Microsoft. It was Software release life cycle#Release to manufacturing (RTM), released to manufacturing on August 27, 2013, and broadly released for retail sale on Octobe ...

, 10 and 11 for desktops, and

Windows Server 2003 Windows Server 2003 is the sixth version of Windows Server operating system produced by Microsoft. It is part of the Windows NT family of operating systems and was released to manufacturing on March 28, 2003 and generally available on April 24, 2 ...

2008 File:2008 Events Collage.png, From left, clockwise: Lehman Brothers went bankrupt following the Subprime mortgage crisis; Cyclone Nargis killed more than 138,000 in Myanmar; A scene from the opening ceremony of the 2008 Summer Olympics in Beijing; ...

and 2008 R2 for servers, do not make use of MS-DOS as a core component of the system. These systems can make use of the FAT file systems which are used by MS-DOS and earlier versions of

Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

; however, they typically use the

NTFS New Technology File System (NTFS) is a proprietary journaling file system developed by Microsoft. Starting with Windows NT 3.1, it is the default file system of the Windows NT family. It superseded File Allocation Table (FAT) as the preferred fil ...

(New Technology File System) by default for security and other reasons. FreeDOS can co-exist on these systems on a separate partition or on the same partition on FAT systems. The FreeDOS kernel can be booted by adding it to the Windows 2000 or XP's NT Boot Loader configuration file,

boot.ini NTLDR (abbreviation of ''NT loader'') is the boot loader for all releases of Windows NT operating system from 1993 with the release of Windows NT 3.1 up until Windows XP and Windows Server 2003. From Windows Vista onwards it was replaced by the ...

, or the freeldr.ini equivalent for

ReactOS ReactOS is a free and open-source operating system for amd64/i686 personal computers intended to be binary-compatible with computer programs and device drivers made for Windows Server 2003 and later versions of Windows. ReactOS has been noted a ...

File systems

FAT32 File Allocation Table (FAT) is a file system developed for personal computers. Originally developed in 1977 for use on floppy disks, it was adapted for use on hard disks and other devices. It is often supported for compatibility reasons by c ...

is fully supported and is the preferred format for the boot drive. Depending on the

BIOS In computing, BIOS (, ; Basic Input/Output System, also known as the System BIOS, ROM BIOS, BIOS ROM or PC BIOS) is firmware used to provide runtime services for operating systems and programs and to perform hardware initialization during the ...

used, up to four Logical Block Addressing (LBA) hard disks of up to 128 GB, or 2 TB, in size are supported. There has been little testing with large disks, and some BIOSes support LBA but produce errors on disks larger than 32 GB; a driver such as OnTrack or EZ-Drive resolves this problem. FreeDOS can also be used with a driver called LFNDOS to enable support for Windows 95-style long file names, but most pre-Windows 95 programs do not support LFNs, even with a driver loaded. There is no planned support for NTFS,

ext2 The ext2 or second extended file system is a file system for the Linux kernel. It was initially designed by French software developer Rémy Card as a replacement for the extended file system (ext). Having been designed according to the same pr ...

exFAT exFAT (Extensible File Allocation Table) is a file system introduced by Microsoft in 2006 and optimized for flash memory such as USB flash drives and SD cards. exFAT was proprietary until 28 August 2019, when Microsoft published its specificati ...

, but there are several external third-party drivers available for that purpose. To access ext2 file systems, LTOOLS, a counterpart to

Mtools Mtools is an open source collection of tools to allow a Unix operating system to manipulate files on an MS-DOS file system, typically a floppy disk or floppy disk image.https://www.gnu.org/software/mtools/ Homepage The mtools are part of the GNU ...

, can sometimes be used to copy data to and from ext2 file system drives.

References

External links

* *
FreeDOS Orphanage
{{DEFAULTSORT:Freedos 1998 software DOS variants Embedded operating systems Floppy disk-based operating systems Free software operating systems Free software programmed in C Microcomputer software Operating system distributions bootable from read-only media Software using the GPL license