FreeDOS

FreeDOS (formerly Free-DOS and PD-DOS) is a free operating system for IBM PC compatible computers. It is intended to provide a complete DOS-compatible environment for running legacy software and supporting embedded systems.

FreeDOS can be booted from a USB stick. It is designed to work under virtualization or x86 emulation.

Unlike most versions of MS-DOS, FreeDOS is made up of free and open source software, licensed under the terms of the GNU General Public License. Therefore, its basic distribution does not require license fees or copyrights and the creation of custom distributions is allowed. However, other packages that are part of the FreeDOS project include non-GPL software that is considered a preserve, such as 4DOS, which is distributed under a modified MIT license.

History

Physicist Jim Hall, a graduate of the University of Wisconsin-River Falls, had an Apple II clone in his youth that initially served as an electronic playground before moving on to programming by teaching himself the Applesoft BASIC language. Over time, the replacement for the team was an IBM PC which also had a version of BASIC to which he migrated his programs without much problem during his studies in high school. During his undergraduate studies at the university, he learned the C language and programmed under the MS-DOS environment.Although UNIX was used in that house of study, Jim Hall continued to use MS-DOS on his personal computers for his academic work. In 1993 he discovers that GNU / Linux is compatible with his computers and installed it in double boot, he recognizes the potential of the new operating system, however, given the large number of utility programs -and games- he decides to stay with MS-DOS..

In 1994, after having tested Windows 3.1, and before the press announcements that it would only go away in a graphical environment and the company Microsoft would abandon the development and support of future versions of MS-DOS, Jim Hall decided to publish the announcement of his project on June 29 on the comp.os.msdos.apps web page. Confused with the concepts of free software and public domain, he decides to name it PD-DOS (Public Domain-Disk Operating System for its initials in English) and it is until the end of July which is re-released under the name Free-DOS and under the GNU General Public License. They finally removed the hyphen and it was left with the current name FreeDOS.

Differences from MS-DOS

FreeDOS includes some features that were not present in MS-DOS:

• Ultra-DMA controller and large disc support (LBA).
• Supports the FAT32 file system.
• DOSLFN Controller to use VFAT long file names.
• Free license (GPL).
• User-defined internationalization support.

Compatibility

With Windows Version 1.0 to 3.xx

It is not possible to start any version of Windows based on MS-DOS in 386 extended mode, you can only start Windows 3.0 in standard mode, Windows 3.1 in standard mode, and Windows versions 1.x and 2.x from FreeDOS. However, it is possible to get around this problem by using a bootloader or similar tool, like the one that comes with FreeDOS, to do a parallel (dual-boot) installation of FreeDOS and the version of Windows in question (choosing between an operating system and another at boot).

With Windows 95 to ME

These versions of Windows are linked to the DOS that they incorporate. It is not possible to run them from FreeDOS, but you can install Windows and FreeDOS on the same C: drive, with the help of a bootloader as described above, or with a GNU/Linux bootloader like LiLo or Grub.

With Windows NT and ReactOS

A parallel installation with Windows NT and ReactOS does not cause problems because these versions no longer use a DOS system as the base system. The FreeDOS kernel can simply be added to the bootloader that these operating systems include.

Waste management

The EMM386 memory management program included with supports VCPI, which allows you to run programs that use DPMI. FreeDOS also contains a UDMA driver for faster disk access, which can also be used in other DOS versions. Disk buffer LBAcache stores recently accessed disk data in XMS buffer to provide even faster access and reduce direct hard drive access (causing less noise)

Because the FreeCOM shell can move itself into extended memory, it is possible to free up a lot of conventional memory: With the kernel stored in high memory and the drivers loaded in the upper memory blocks, 620KB (620*1024 bytes) of conventional memory can be made available, which is useful for DOS-demanding programs and games.

Features

The license is free. It has support for FAT32 partitions, from which it can boot. Depending on the BIOS used, LBA hard drives of up to 128 Gb or even 2 TB can be used. Some BIOSes support LBA but have a bug with drives larger than 32 GB; Drivers like OnTrack or EzDrive can "fix" that problem. FreeDOS can also be used with a driver called DOSLFN that supports long filenames (see VFAT), but most FreeDOS programs DO NOT support long filenames, even if the driver is loaded (EDIT.COM for Windows 9x does support long names if the driver is loaded).

There are no plans to add NTFS or ext2fs support to FreeDOS, but there are several shareware drivers available for that purpose. To access ext2fs partitions, you can use the LTOOLS tool, which can copy information to and from ext2fs partitions. By running FreeDOS on DOSEmu (a PC/DOS emulator for GNU/Linux systems) it is possible to install DOS applications on any file system and hard drive that supports GNU/Linux.

No USB support is planned either, only USB devices recognized by the BIOS are available first hand to FreeDOS. You can use free drivers, or run FreeDOS in a DOSEmu window and let it use whatever drive is accessible to GNU/Linux.

Other popular PC and DOS emulators are Bochs (simulates a complete PC) and DOSBox, which simulates a PC with a DOS kernel and its interpreter: Programs inside DOSBox "come" a DOS, but can't install FreeDOS or another kernel. However, FreeDOS tools are fully functional in DOSBox

The FreeDOS kernel is also supplied with DOSEmu. DOSEmu simulates a PC in an optimized way allowing the use of simplified drivers (provided with DOSEmu). The system runs much faster than with the GNU Bochs PC simulator or the commercial VMware emulator. However, the hardware simulation lacks realism in some respects: Accessing the simulated disk through the virtual BIOS works fine, but DOS programs cannot program the virtual disk drivers. However, there is virtual graphics and sound hardware

Example output

C:purdir
Volume in drive C is FREEDOS
Volume Serial Number is 4228-11FA

Directory of C:

KERNEL SYS 45,293 08-18-06 11:32a
COMMAND COM 86,413 08-18-06 12:17a
DOS ≥DIRMON 11-14-02 10:43a
FDCONFIG SYS 263 11-14-02 11:05a
EDIT EXE 62,277 08-11-04 7:38p
EDIT HLP 29,452 04-28-04 1:22a
5 file(s) 219,698 bytes
1 dir(s) 5,402,624 bytes free

C:pur

Distribution

Blinky

Due to an agreement with Microsoft, which prevented computer vendors from selling computers without an operating system installed, Dell Computer offered some of its "series" with FreeDOS pre-installed.

The FreeDOS project began providing an alternative to MS-DOS when Microsoft announced in 1994 that it would stop selling and supporting its MS-DOS.

An alternative to FreeDOS is OpenDOS and EDR-DOS Enhanced DR-DOS. This DOS is more compatible with Windows, but the license is more restrictive. OpenDOS is based on DR-DOS, owned by DeviceLogics and offered as shareware, and Enhanced DR-DOS is based on OpenDOS.

Since 2014, the mascot of this operating system has a specific name: Blinky.