FREEDOS INFORMATION SHEET

Jim Hall <jhall1@isd.net>
v.1.1, updated 25 Feb 1999


This document provides some basic information on what FreeDOS is, what
hardware it runs on, and what you can do with it.


1. INTRODUCTION

  The goal of the FreeDOS Project is to create another implementation of
  MS-DOS. DOS is a popular system, and there is plenty of PC hardware
  already available that is ready to support it. Microsoft will not
  develop DOS forever, and one cannot count on third-party commercial
  entities to continue DOS. I feel it is then up to those on the
  Internet to develop their own DOS (FreeDOS) and I feel there is a lot
  of support for this type of project.
  
  FreeDOS should not be targetted towards certain users. That is, the
  end product should be something that programmers and non-programmers
  may both enjoy and find useful.
  
  
2. FEATURES
  
  We intend to write a free replacement for MS-DOS; therefore, our first
  goal must be to achieve MS-DOS compatibility. We have chosen to become
  compatible with MS-DOS 3.3, because it is our opinion that MS-DOS 4.x,
  5.x, and 6.x are really just improvements upon MS-DOS 3.3. Expanded
  memory support was improved, and some other things fixed, but on the
  whole the underlying DOS kernel didn't change that much.
  
  The MS-DOS 3.3 compatibility extends only to the FreeDOS
  kernel. FreeDOS programs should be compatible with MS-DOS 6.22,
  because those are the features that users will be most familiar with.
  
  
3. HARDWARE ISSUES
  
  FreeDOS was designed to be compatible with all PC hardware, from
  systems as low as the XT and systems with as little as 640k memory.
  However, not all PC hardware was created equal, and there is odd
  behaviour of some computers (mainly old ones, but there are bugs in
  the new CPUs too).  FreeDOS might be a candidate for upgrading old
  computers, some of which will be strange.  Mark Aitchison lists a few
  systems that are known to have issues with FreeDOS:
  
  * Cyrix 486DLC CPUs (made by Texas Instruments) cause trouble for many
    systems, but I'm not sure of the details. (I do have a DLC I can get
    my hands on to test, though).
  
  * Sanyo MBC 500 series computers are extremely incompatible in most
    ways; the BIOS only partially matches IBM PCs but the memory map,
    video hardware, etc are very different.  The MBC 750 series is a bit
    more compatible, I heard.
  
  * Data General DG10 - this is a desktop minicomputer with DG's own
    microEclipse CPU and an 8086 side by side; it can run two operating
    systems at the same time, and each opoerating system uses the other
    CPU at times (e.g. the DG CPU handles all disk activity, the 8086
    handles keyboard).  The MSDOS available for it was greatly hacked by
    DG, and (like the MBC550) video RAM and IO ports aren't where you'd
    expect them.  Both the DG10 and MBC500 series don't have ROM at the
    the top of conventional memory, so you cannot test for a BIOS
    signature (in fact reading upper memory can hang the computer or do
    strange things to the video) although it is probably that the
    manufacturer's ID word with be zero for both machines.
  
  * Data General DG One - totally different to the DG 10, a laptop (the
    first decent one, IMHO), with a 4MHz 80C88.  Much more compatible
    with an IBM PC, but the serial ports are different (int 14 okay, but
    hardware access involves a totally different UART on the first DG
    One), and the CMOS time/clock behaviour is different (cannot recall
    details, but a regular DOS would set the time correctly but not the
    date, I think). I can get hold of one to test.
  
  * Olivetti M20 series - pretty incompatible (M24 not as bad as M20);
     the Machine ID word is 0xFE00 for the M20. Note low byte is zero,
     normally FF for an IBM PC, FE for an XT, etc.
  
  * In general, if the ID byte at f000:fffe isn't in the range 0xfa to
    ff then expect compatibility problems. The ID words for clones I
    have come across are:
  
          ??2D very old Compaq PC
          ??9A very old Compaq XT
          0036 "Magnum" or "Bison" XT clone
          CA00 "Excel" XT clone
          FE00 Oliv. M20
          0000 Data General DG10 or Sanyo MBC550
  
  
4. SUPPORTED SOFTWARE
  
  Pretty much any software that works on MS-DOS (or compatible DOS) will
  work on FreeDOS.  At the moment (Dec 1998) the redirector interface
  and direct disk support is missing from the kernel, which means that
  some software will not work.  Notably, CD-ROM extension software and
  disk maintenance tools will be broken.  This support is being added to
  the kernel.
  
  
5. WHO USES FREEDOS?
  
  Many people use FreeDOS, in business and education and at home.  At
  this time, it is impossible to know for certain exactly who is using
  FreeDOS, or in fact how many people use FreeDOS.  However, I have seen
  comments from people that indicate FreeDOS is being used in at least
  these ways:
  
  * As the DOS for Linux DOSEmu.  Also note that the Linux DOSEmu
    project uses FreeDOS as the default DOS.
  
  * As a desktop operating system in a home business.  FreeDOS runs
    DOS-based word-processors just fine!
  
  * In embedded systems.
  
  * As an educational tool, to teach students the fundamentals of
    programming and operating system design.
  
  
6. HOW TO GET IT
  
  There are many ways to obtain FreeDOS:
  
6.1 CD-ROM
  
  Various distributors already include FreeDOS on their CD-ROM sets.
  Red Hat Software <http://www.redhat.com> sells an FTP site archive
  CD-ROM set for $25, and this includes a copy of FreeDOS.
  
  
6.2 INTERNET
  
  The official FreeDOS home page is <http://www.freedos.org> and you
  will always be able to download FreeDOS from this location.  Jim Hall
  currently acts as the FreeDOS release coordinator, and he lists mirror
  sites at <http://www.isd.net/jhall1/freedos/mirrors.html>.
  
  
7. LEGAL ISSUES
  
  Any effort that goes into writing a FreeDOS would, of course, be
  redistributed in both binary and source code form. Therefore, we urge
  programmers to release their software under a distribution agreement,
  such as the GNU General Public License (GPL), which says in part from
  its Preamble:
  
      The licenses for most software are designed to take away your
    freedom to share and change it.  By contrast, the GNU General Public
    License is intended to guarantee your freedom to share and change free
    software--to make sure the software is free for all its users.  This
    General Public License applies to most of the Free Software
    Foundation's software and to any other program whose authors commit to
    using it.  (Some other Free Software Foundation software is covered by
    the GNU Library General Public License instead.)  You can apply it to
    your programs, too.
    
      When we speak of free software, we are referring to freedom, not
    price.  Our General Public Licenses are designed to make sure that you
    have the freedom to distribute copies of free software (and charge for
    this service if you wish), that you receive source code or can get it
    if you want it, that you can change the software or use pieces of it
    in new free programs; and that you know you can do these things.
  
  Anyone may sell a GPL'd operating system (such as FreeDOS) so long as
  there is a distinction made as to what the customer is actually
  buying. That is, it must be made clear that the distributor is not
  claiming that they own or wrote the GPL program, and that they don't
  reserve any rights to it.
  
  Additionally, the distributor must understand that any changes they
  make are to be identifed and must be released freely. For example, if
  someone adds FAT32 support into the FreeDOS kernel, then it falls
  under GPL and must be freely available. However, if they add FAT32
  support as a TSR and simply bundles it with the rest of FreeDOS, then
  they can charge for that piece of code only.
  
  The idea is to protect the free software and their authors. No one
  else should be able to take their code and misrepresent it, or worse,
  illegally or unethically profiting from it.
  
  
8. THIS DOCUMENT
  
  This document is maintained by Jim Hall <jhall1@isd.net>.
  Please mail me with any comments, no matter how
  small.  I can't do a good job of maintaining this document without
  your help.  A more-or-less current copy of this document can always be
  found at <http://www.freedos.org/fd-doc/>.

  Copyright (C) 1998 Jim Hall <jhall1@isd.net>

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  If you have any questions, please contact the FD-DOC coordinator
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