Visual Operating System. MikeOS - simple x86 assembly language operating system. AROS Research Operating System. Pinguy OS. The MINIX 3 Operating System. FreeRTOS-A Free RTOS for ARM7, ARM9, Cortex-M3, MSP430, MicroBlaze, AVR, x86, PIC32, PIC24, dsPIC, H8S, HCS12 and 8051.
Operating system and the Neanderthal theory. Haiku Project. The FreeDOS Project. An OEM Upgrade to IBM OS/2. Right for today's PC hardware. DevCon (eCo Software Developer Connection) - for developers of applications and drivers for eComStation / IBM OS/2 Warp. En:start - osFree.