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Kernels of DOS

DRDOS DOS

Introduction

While DOS doesn’t know the privileges levels and all proceses running in computer has the same rights the term kernel isn’t so clear as in other operating systems. However in DOS world is under word “kernel” meant set of services running in minimal configuration without any additional drivers loaded in CONFIG.SYS, AUTOEXEC.BAT or loaded by any other way.
For people accustomed to modern OSes is suprising how minimalistic the DOS kernel is. It offers only functions around diskettes and harddisks, some basic memory management, very simple services around keyboard and screen and only few others. All above must be done by external loadable drivers.
This minimalism is due the fact that in 80′s when first versions of DOS were written the PCs didn’t have todays usual hardware like soundcards or powerful graphics cards.
It can be considered as a advantage or disadvatage.
Advantage because in this approach everybody can configure personalised system exactly satisfying his needs. And disadvatege because it leads to problematic heterogenity what complicates writting a reliable software.
Kernel minimalism leads to interresting fact that as easily like changing one driver to another one you can as easily change the kernel without any problems. It is completely unthinkable for Windows users and it is a complicated task for Linux users but in DOS world it is absolutely normal.

Which kernel?

There was written many DOS kernels from origins to present days. As a standard are referred the various versions of MS-DOS by Microsoft. For ability to run most programs you should use at least version MS-DOS 5.0 or equivalent other DOS. But very probably you will need to use MS-DOS 7.1 or equivalent because it is the first version which brings support for filesystem FAT32 and disk partitions bigger than 2GB.
It is very likely that you have such disk (partition) so all DOSes bellow 7.1 can be considered as obsolete and not recomended. However there is one reason why to decide for older DOS, in particular MS-DOS 6.22. The reason is Microsoft Windows 3.1 and Windows 3.11 because it will not run under MS-DOS 7.0 and above (at least without any wild and for me unknown hacks). Fortunately there also exist other DOSes which can do both - handle FAT32 filesystem and run Windows 3.x.
Note: none version of PC-DOS by IBM supports FAT32. Even the last version PC-DOS 2000 doesn’t! In next text will be described only FAT32 capable DOS kernels.

MS-DOS 7.1

Is a part of Windows 98. You can boot into it by pressing F8 when starting windows. Another possibility is to booting from booting diskette or backward instalation from booting diskette. Or you can edir edit MSDOS.SYS file to disable starting Windows GUI. This kernel has a notable advantage - it exists in all language versions like Windows.
Reportedly there was also a standalone MS-DOS 7.1 version (not supplied with Windows) but was sold only in China. However it is difficult to validate such information and distinguish if it isn’t some pirat version.
Who is this kernel recomended for:
Users needing absolutely 100% compatibility with MS-DOS, people needing the localisation

More informations about various MS-DOS version is on separated page http://www.unet.univie.ac.at/~a0503736/php/drdoswiki/index.php?n=Main.MS-DOS

LZ-DOS 7.1

It is only kernel, without any included standard utilities so you will need these utilities from some other DOS. On it’s web site is written that it is absolutely 100% compatible with MS-DOS 7.1.
It is true because it is almost without doubts a hacked version of MS-DOS 7.1 by russian pirats. The advantage over MS-DOS is its compressed kernel so it is very useful for various boot diskettes. And some people say that it can besides Windows 9x also run Windows 3.xx
Who is this kernel recomended for:
People which absolutely doesn’t care about copyrigths and software legality and which need a space on booting diskettes.

Standard DR-DOS

In all history of MS-DOS, the DR-DOS was it’s competitor. It is good kernel, with some interesting features but also with some disadvantates. It has more powerful memory manager offering agresive memory management and supporting own standard DPMS http://www.unet.univie.ac.at/~a0503736/php/drdoswiki/index.php?n=Main.DPMS Other nice feature is it’s taskswitcer/taskmanager. However DR-DOS it isn’t perfectly compatible with MS-DOS and you quite often find a program not working or crashing under DR-DOS.
Second huge disadvantage is disability to boot from FAT32 partition. You must boot from FAT16 and FAT32 partitions mount via external driver. And there are reports that even this doesn’t work very well because this driver is quite buggy. And it can’t be used with other DOS kernel.
Who is this kernel recomended for:
People not needing reliable FAT32 support and MS-DOS compatility but interrested in it’s taskswitcher, people running Windows 3.xx

Enhanced Dr-DOS

Is the live development branch of DR-DOS created by Udo Kuhnt. The project page is here: http://www.drdosprojects.de It fixes some bugs of standard DR-DOS, mainly adds the ability for booting and accessing FAT32 partitions. However the compatibility with MS-DOS is still not OK and it has problems with some boot managers (f.e. with System Commander). Additional feature is experimental support for FAT+ filesystem. http://www.unet.univie.ac.at/~a0503736/php/drdoswiki/index.php?n=Main.FATplus
Who is this kernel recomended for:
Same people like above plus but also users needing reliable FAT32 support

More info here: http://www.unet.univie.ac.at/~a0503736/php/drdoswiki/index.php?n=Main.AboutDr-DOS

FreeDOS

http://www.freedos.org
Open source DOS kernel still in active development (written in 8/09). It offers almost 100% compatibility with MS-DOS, definitely better than (E)DR-DOS. Works reliably and very good. Note that FreeDOS is not only kernel but also all standard utilities and also various drivers usually far superseding their counterparts from MS-DOS. Some of them can’t be reffered as a part of FreeDOS but FreeDOS is usually the primary kernel what are these utilities and drivers tested for. The disadvantage is yhe limited support for Windows 3.xx - runs only Windows 3.1 in standard mode (not in enhanced mode)
Who is this kernel recomended for:
For virtualy everyone except users needing Windows 3.11

RXDOS

Datalight DOS

Others

DR-DOS

DOS