FreeDOS
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FreeDOS is an open source project with the stated goal of creating a free operating system that is 100% compatible with MS-DOS and its device drivers. Although still in its beta phase, the project has achieved most of its goals and is currently highly compatible with MS-DOS. The Dell computer manufacturing company currently offers a desktop computer with FreeDOS pre-installed as an alternative to the Microsoft operating systems that are usually packaged with new desktops.
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Differences from MS-DOS
- Open source/Free license (GPL)
- User-editable internationalization support
- FDAMP - APM control/info, energy saving TSR/control, cache flush, rebooting, and ASPI support
- UltraDMA driver and support for big disks (LBA) (can also be used in MS-DOS)
- LBACACHE - disc cache (SMARTDRV in MS-DOS)
- FDCDEX and CD-ROM driver (MSCDEX in MS-DOS)
- CTMOUSE - Mouse driver with wheel-support (can also be used in MS-DOS)
FreeDOS supports FAT32 file system (except for a few FreeDOS commands, such as DEFRAG), whereas MS-DOS versions prior to 7.10 do not. Also, Long File Names (LFN) APIs (which can be provided by the DOSLFN driver or similar) and large disks (LBA) are not supported by MS-DOS 6.x (or earlier), and most of the FreeDOS programs.
Compatibility
Windows 1.0 through 3.xx
FreeDOS seems to work fine with 1.0 and 2.0 versions of Windows. 3.x versions are harder to run; the simplest command that currently works for version 3.1 is WIN /S, which forces the Windows kernel to run in 16-bit 286 mode rather than the preferred 32-bit 386 mode.
To date Windows 3.11 (Windows for Workgroups) has not been successfully started under FreeDOS.
Windows 9x and ME
Those Windows versions contain and are linked to MS-DOS. One cannot run them in FreeDOS, but it is possible to install Windows and FreeDOS on the same drive, with help of a boot manager like LILO or GRUB.
Windows NT through XP
A parallel installation with Windows NT/2000/XP doesn't cause problems because these versions don't use a DOS system as a base operating system anymore and they are shipped with a simple boot manager. The FreeDOS kernel can simply be added to Windows' boot.ini to enable its selection in the boot manager. (By adding a boot sector file or drive to the list - FreeDOS will always search the first FAT16 or FAT32 drive for fdconfig.sys or config.sys, even if you boot it from another harddisk drive letter...)
ReactOS
FreeDOS interacts with ReactOS in a similar manner to Windows NT, 2000, and XP.
Memory Management
The EMM386 memory management program included with FreeDOS now supports VCPI, which allows programs and DOS extenders which use DPMI to run. FreeDOS also contains an UDMA driver for faster disk access, which can be used for other DOS versions, too. The LBAcache disk cache buffers recently-accessed disk data in Extended Memory Specification memory for even faster access and less direct access (reduced noise) to the harddisk.
The FreeCOM command line shell can swap portions of itself to XMS, making it possible to free up a large amount of RAM in the 640 kB region for DOS programs to use. With proper configuration, 620 kB and more can be available. This can be useful for memory-hungry DOS games.
Characteristics
There are many ways in which FreeDOS is considered better than MS-DOS. The license is free and the software is actively being developed. FAT32 support is implemented and it is possible to boot from FAT32 drives using FreeDOS. Depending on the BIOS used, up to four LBA hard disks up to 128 GB or even 2 TB in size are supported. Some BIOSes support LBA but have a bug for disks bigger than 32 GB. One can use a driver like OnTrack or EzDrive to "repair" that problem. FreeDOS can also be used with a driver called DOSLFN which supports long file names (see VFAT), but most FreeDOS programs do NOT support long file names even if the driver is loaded.
There is no planned support for NTFS or ext2fs but there are several shareware drivers available for that purpose. To access ext2fs, you can use the LTOOLS (counterpart to MTOOLS) which can copy data to and from ext2fs drives.
If FreeDOS is started from a DOSEmu (PC/DOS emulator for Linux systems) window it is possible to install DOS applications on any Linux supported file system and hard disk. There is no USB driver support planned, in many cases only BIOS supported USB devices are available for plain FreeDOS. One can also try some DOS USB drivers (such as USBASPI and USBMASS drivers, although they are mainly designed for use with MS-DOS) for other USB storage devices, or run FreeDOS in a DOSEmu window and let it use any drive which can be accessed from Linux that way. Other popular PC emulators and DOS emulators are Bochs (simulates a whole PC) and DOSBox, which simulates a PC with a DOS kernel and shell simulation: Programs inside DOSBox "see" a DOS, but you cannot install a FreeDOS or other DOS kernel. You can, however, use FreeDOS tools inside DOSBox.
The FreeDOS kernel is also shipped with DOSEmu. DOSEmu supplies a DOS optimized simulation of a PC which allows the use of simplified drivers (shipped with DOSEmu). The system runs much faster than the PC simulator Bochs. However, the simulation of raw hardware lacks realism in some aspects: Simulated disk access through the virtual BIOS works fine, but DOS programs cannot program the virtual disk controllers. There is virtual graphic and sound hardware, though.
Distribution
As a result of license agreements with Microsoft, which oblige computer manufacturers not to ship computers without operating systems, Dell Computer offers some of their n-series systems with pre-installed FreeDOS. <ref>http://www1.us.dell.com/content/products/compare.aspx/optix_n?c=us&cs=04&l=en&s=bsd</ref>The company has come under fire for making the FreeDOS-powered machines no cheaper and more difficult to purchase than identical systems running Windows.
When Microsoft announced in 1994 that they would discontinue the sale and support of MS-DOS, FreeDOS was started to provide an alternative to MS-DOS by a group of programmers who still believed that DOS is a great OS that should still be used. The only other DOSes that are actively distributed now are FreeDOS, DR-DOS, and OpenDOS.
One alternative to FreeDOS is OpenDOS. This DOS is more compatible with Windows, but the license is less free. OpenDOS is a derivative variant of DR-DOS, which is owned by DeviceLogics and offered under shareware-like terms. DR-DOS offers a good memory manager (EMM386, here with a built-in DPMI host and multitasking support and XMS/EMS memory pool sharing) and real preemptible multitasking.
Although Microsoft still supplies very basic DOS-like functionality in Windows NT called CMD<ref>http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/cmd.mspx?mfr=true</ref>, it is only useful for a few basic tasks such as making folders or formatting disks as some of the more complex and less-well known DOS commands are not in the program.
References and further reading
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See also
External links
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