fdpp is a 64-bit DOS core.
It is based on a FreeDOS kernel ported to modern C++.
In short, FreeDOS plus-plus.
Can be compiled with clang (not gcc!) and booted under dosemu2.
Just run make.
For an out-of-tree build, run <path_to_fdpp>/configure
before running make.
After compiling, run sudo make install to install.
For the ubuntu package please visit this PPA.
The simplest way to get it running is to use
dosemu2.
After installing fdpp, you can (re-)build dosemu2.
It will then find fdpp during build, and enable its support.
You can also get the pre-built dosemu2 packages with
fdpp support enabled from the aforementioned
ubuntu PPA.
fdpp uses fdppconf.sys file at boot. This file has the standard format of config.sys with some syntax extensions. It is fully backward-compatible with the DOSish config.sys, and if fdppconf.sys is missing, config.sys is attempted instead.
fdpp is a user-space library that needs a couple of call-backs to be provided to it by the host program. This means it can't be booted from the bare-metal PC, as the original freedos could. But all it needs is a few call-backs for running real-mode code. So if you want to run it on something other than dosemu2, please use this code as a reference implementation. Sufficiently DOS-oriented kernels like freedos-32 are good candidates for running fdpp.
A meta-compiler that was initially able to compile the freedos kernel from its almost unmodified sources. As the project advances, the ability to compile freedos from the unmodified sources have lost its value, as our copy of freedos is now heavily modified. The main tasks of our meta-compiler is to parse FAR pointers and generate thunks to real-mode asm code of freedos.
fdpp removes some compatibility hacks that FreeDOS had. For example it doesn't play tricks with disabling A20 when returning to user code, so you may see "Packed file is corrupt" message on some old exe files. Using "loadfix" command avoids that problem. On the other hand fdpp supports much more games than does freedos. If you find some compatibility problem, please report a bug.
fdpp can work in any environment with STL/C++ runtime support. Requirements to the standard libraries are very small, far within the ISO standards. No posix or OS-specific APIs are used. The build requirements are in line with today's posix-compatible environments: you'll need the full stack of tools like bison, autoconf, sed etc. Additionally you'll need a clang tool-chain as clang++ is the only compiler to build fdpp with. That said, building fdpp under itself may be a challenge. :)
FreeDOS kernel is a DOS-compatible kernel that is used as a core of fdpp.
dosemu2 is a virtual machine that allows you to run DOS software under linux. It is a primary host platform for fdpp.
comcom32 is a 32bit command.com that is supposed to be used with fdpp while we don't have a 64bit one.
dosbox has a good built-in DOS written in C++. It is tightly coupled to dosbox; you can't easily port it to your project, whereas fdpp is designed to be plugable. Also it uses host APIs and libraries for filesystem access, CD-ROM playing and similar things. fdpp uses no host APIs or libraries, which may be good or bad, depending on your use-case. dosbox is cleanly written in C++, whereas fdpp wraps the C-coded freedos kernel into a C++ framework, resulting in a nuclear C/C++ mix.
freedos-32 is a kernel written with DOS compatibility in mind. It has a rich user-space part with libc. Very good candidate for running fdpp. Unfortunately, the kernel was scrapped, and currently something else is being developed.
freedos-64 seems to be a project planning to implement a 64bit kernel around the real-mode freedos kernel.
NightKernel
is A 32-bit drop-in replacement for the FreeDOS kernel, as
they call themselves. In fact, it is an assembly-written
ring-0 kernel, currently w/o any DOS compatibility at all.
Can't be used to run fdpp because it doesn't support user-space
add-ons.
