FREEDOS INFORMATION SHEET Jim Hall 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 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 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 . 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 . 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 . Copyright (C) 1998 Jim Hall Unless otherwise stated, FD-DOC HOWTO documents are copyrighted by their respective authors. FD-DOC HOWTO documents may be reproduced and distributed in whole or in part, in any medium physical or electronic, as long as this copyright notice is retained on all copies. Commercial redistribution is allowed and encouraged; however, the author would like to be notified of any such distributions. 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