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 much like it does with
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 XMS memory for even faster access and less
direct access (reduced noise) to the harddisk.
With help of the ability of the FreeCOM command line shell to swap itself to
XMS, it is possible to get much low DOS RAM free: With kernel and BUFFERs in
HMA and drivers (where compatible with this) loaded to UMBs, 620k (620*1024
bytes) and more can be available. Useful for memory-hungry DOS games.
Characteristics
Some advantages of FreeDOS: 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, 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.
You 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's possible to install DOS applications on any Linux supported file system and
hard disk. Also there is no USB driver support planned, only BIOS supported
USB devices are available for plain FreeDOS. You can use some proprietary but free
drivers 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 GNU PC simulator Bochs or the commercial
emulator VMware. 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 a license agreement with Microsoft, which obligated computer
manufacturers not to ship computers without operating systems, Dell Computer
offered some of their n-series systems with pre-installed FreeDOS.
FreeDOS was set up to provide an alternative to MS-DOS when Microsoft announced
in 1994 that they were going to discontinue the sale and support of MS-DOS.
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.
See also: GEM, ReactOS, FreeDOS 32
External links
Source | Copyright
