Operating Systems

• Linux Distributions
• Posix

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• InfiniteOS   
  InfiniteOS is an open source operating system for the Mac, released under the GPL. Currently it has no GUI, only a Command Promt.
  
  http://ios.sourceforge.net/

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• legOS   
  legOS is an open-source embedded operating system for the LEGO Mindstorms, a LEGO brick with a brain. It's open source available under the GNU Lesser General Public License (LGPL).
  
  http://www.noga.de/legOS/

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• GeckOS/A65   
  Full-featured, preemptive multi-tasking/threading operating system for 6502. Implements some Unix-like features: multithreading, dynamic memory management, relocatable fileformat, lib6502 standard library, internet support.
  
  http://www.6502.org/users/andre/osa/

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• Cefarix Operating System   
  Open source, 32-bit protected mode OS for x86 and later PowerPC systems.
  
  http://cefarix.sourceforge.net/

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• The FreeBSD Project   
  FreeBSD is an advanced operating system for x86 compatible architectures. It is derived from BSD, the version of UNIX
  
  http://www.freebsd.org/

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• The NetBSD Project   
  NetBSD is a free, secure, and highly portable Unix-like Open Source operating system available for many platforms.
  
  http://www.netbsd.org/

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• The OpenBSD project   
  OpenBSD.org produces a FREE, multi-platform 4.4BSD-based UNIX-like operating system.
  
  http://www.openbsd.org/

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• FreeDOS   
  It is complete, free, 100% MS-DOS compatible operating system with no enhancements or advanced features such as multitasking, protected mode operation, GUI.
  
  http://www.freedos.org/

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• OpenVMS   
  Product information, FAQs and online documentation for OpenVMS.
  
  http://h71000.www7.hp.com/

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