+<div id="outline-container-sec-2-1" class="outline-3">
+<h3 id="sec-2-1"><a id="ID-c19c5a3b-dfb0-4f7f-961c-a387b925669f" name="ID-c19c5a3b-dfb0-4f7f-961c-a387b925669f"></a><span class="section-number-3">2.1</span> Extensible, programmable computing environment examples</h3>
+<div class="outline-text-3" id="text-2-1">
+<ul class="org-ul">
+<li><a href="https://www.johndcook.com/blog/2008/04/27/one-program-to-rule-them-all/">GNU Emacs</a> - At the heart, Emacs is text editor on top of Lisp
+runtime. Data storage and computation can be done in <a href="https://www.defmacro.org/ramblings/lisp.html">Lisp</a>. Lisp is
+on itself programmable programming language where new paradigms can
+be added dynamically. Domain specific languages to fit particular
+problem could be developed as needed and Emacs extended to support
+those languages. Emacs provides text buffers that can be used to
+build user interfaces. So you can customize Emacs and Lisp to fit
+any problem domain.
+</li>
+
+<li><a href="https://www.eclipse.org/ide/">Eclipse IDE</a> - In essence <a href="https://en.wikipedia.org/wiki/OSGi">OSGi</a> platform with a text
+editor. Computation done in java. Eclipse provides integration,
+runtime and GUI platform. One can develop Eclipse plugins to add
+necessary logic and visual parts to fit any problem. (IntelliJ and
+NetBeans have similar properties)
+</li>
+
+<li><a href="https://en.wikipedia.org/wiki/IBM_Notes">IBM Notes/Domino</a> - Custom database engine, software development
+platform, GUI editor, computation can be done in Java and
+LotusScript. You can build distributed business applications on it
+as a platform.
+</li>
+
+<li><a href="https://en.wikipedia.org/wiki/ABAP">SAP ABAP</a> - Custom database engine, runtime, GUI platform,
+development environment and programming language. Is being used as a
+platform to build business applications with any logic and UI.
+</li>
+
+<li><a href="https://en.wikipedia.org/wiki/Microsoft_Access">Microsoft Access</a> - Database management system that combines
+relational database engine with a graphical user interface and
+software-development tools.