GeekOS is a tiny operating system kernel for x86 PCs. Its goal is to be simple enough for beginners to understand and modify, but realistic enough to be interesting and fun. The primary development environment for GeekOS is Linux or Windows using gcc, nasm, and the Bochs PC emulator.
SOSSE (Simple Operating System for Smartcard Education) is a free smart card operating system. It is implemented in C and assembler for the Atmel AVR smart cards (Funcard, PinkCard, Jupiter). The aim of this project is to provide something like Linux for smart cards, which is a market full of NDAs. SOSSE should make it possible to learn about smart cards, and to implement and test your own ideas.
Libecc is a C++ elliptic curve cryptography library that supports fixed-size keys for maximum speed. The goal of this project is to become the first free Open Source library providing the means to generate safe elliptic curves, and to provide an important source of information for anyone with general interest in ECC.
Flat Assembler is a fast and efficient self-assembling 80x86 assembler. It supports x86 and x86-64 instruction sets with MMX, 3DNow!, SSE up to SSE4, AVX, AVX2, and XOP extensions. It can produce output in binary, MZ, PE, COFF, or ELF format. It includes powerful but easy-to-use macroinstruction support and does multiple passes to optimize the instruction codes for size. It is written entirely in assembly language.
Agnix is a small, educational operating system kernel for i386, supporting 32-bit protected memory mode, paging, hardware switched tasks, memory tests, PCI bus, devices, PCI IRQ routing, RT timers, network protocols. It is available with all the source code and is fully compatible with the Linux kernel API.
Buenos is a small SMP operating system skeleton that can be used as a base for operating systems project courses. The system is intended to be used as OS project base code which students can improve. Extensive documentation with suggestions for assignments or exercises is included with the system. It runs in a machine simulator called YAMS, which is its sister project.
The HLA Standard Library was developed to support the High Level Assembler (HLA), but could be used with other assemblers or higher-level languages if the necessary headers were developed. It supports 32-bit versions of Windows, Linux, Mac OS X, and FreeBSD, and is written entirely in HLA. It includes the following modules: args, arrays, bits, chars, console, conversions, cset, date, environment, exceptions, file class, file I/O, filesys, lists, math, memory-mapped files, patterns, RNG, stderr, stdin, stdout, strings, tables, time, timer, zstrings, sockets, threads, and blob. An automated test suite is included.