Welcome to FreeDOS

Jemm is an "Expanded Memory Manager" (EMM), based on FreeDOS Emm386. Jemm comes in two versions: Jemm386: standard version which needs an external eXtended Memory Manager, and JemmEx: extended version which has an XMM already included. Japheth recently released a new version: v5.85 has several fixes and new features, including fixed: VDS func ax=810Ch: set ZF if disable cnt reaches zero, fixed: VDS: added several argument checks, fixed: ISA DMA ports 000A-000F must be handled by Jemm to detect FD access, and linear address region 110000-3FFFFF is now only mapped as far as needed by the monitor program. Thanks, Japheth! You can find the new version at Jemm's GitHub. We've also mirrored this in the FreeDOS Files Archive at Ibiblio, under /files/dos/emm386/jemm

If you're following along with the latest development tools, you may be interested in JWasm, a MASM-compatible assembler. Version 2.19pre2 fixes bugs like format mz: stack segment was never written, format mz,pe: start offset for first segment may have resulted in an invalid binary, and fastcall 32-bit (MS style): registers may have held float arguments. Other changes include write listing reworked, option -pe: add segments with combine type stack, and .model flat: ensure variables in 16-bit segments can be accessed directly if segment register is assumed flat. You can find this pre-release version at JWasm on GitHub.

AMB stands for "Ancient Machine Book". It is an extremely lightweight file format meant to store any kind of hypertext documentation that may be comfortably viewed even on the most ancient PCs: technical manuals, books, etc. Think of it as a retro equivalent of a CHM help file. Mateusz Viste recently released a new version of AMB. Version "20250110" (that's "January 10, 2025") includes patches kindly contributed by Jens Guenther: fixed screen garbling on PGUP, and added handling of HOME and END keys. Download the new version from AMB on SourceForge. We've also mirrored this in the FreeDOS Files Archive, in /files/dos/help/amb.

Bob Smith of Sudley Place Software has released the source code of 386MAX and related tools under the GNU GPL! 386MAX is a computer memory manager for DOS, and has two neat features: 1. 386MAX supports the Global EMM Import Specification (GEMMIS), which allows Windows 3.x to start in 386 Enhanced mode, even when the EMM manager is loaded. 2. 386MAX supports the same I/O port trapping API through INT 2fh that EMM386 provides. See also DPMIONE, a standalone DPMI 1.0 Host, which is also under the GNU GPL. Bob also has a protected mode debugger called 386SWAT, and a linker called QLINK written specifically to link 386SWAT. Thanks Bob!

PMODE/W is a DOS extender for use with the Watcom C/C++ compiler. It is designed to be a fairly functional drop-in replacement for DOS4GW.EXE. From the website: "Whereas DOS/4GW requires a stub and an large external extender, PMODE/W is the stub and extender in one. The generated executable contains the PMODE/W extender within it as the stub. When run, PMODE/W will take care of setting up the system and executing the protected mode portion of the program." PMODE/W is released under the MIT license. Download version 1.33 from the PMODE/W website.

Darik Horn has announced a version of 7-Zip 24.09+2 for DOS with several enhancements and improvements. This version supports automatic dictionary sizing, and provides a new 7zm.exe mini build that can create 7z files on a computer with a 386 cpu and 3 megabytes of memory. Improvements include LFN detection and SFN globbing. Darik also notes that "7-Zip was expressing bugs in DOS/32A and the OpenWatcom runtime that were resolved, in part, by using the Causeway extender." You can get the new 7-Zip 24.09+2 for DOS at the retro7zip GitHub.