```Interactive Environments:

Mathematica:
http://www.wolfram.com/
Maple:
http://www.maplesoft.com/
Maxima:
http://maxima.sourceforge.net/
diff(sin(x)/x,x);
plot2d(sin(x)/x,[x,-20,20]);
SAGE:
http://www.sagemath.org/
MATLAB:
http://www.mathworks.com/
Octave:
http://www.gnu.org/software/octave/
gnuplot:
http://www.gnuplot.info/
Scilab:
http://www.scilab.org/
R:
http://www.r-project.org/
Gnumeric:
http://www.gnome.org/projects/gnumeric/
Calc:
http://www.openoffice.org/product/calc.html
Blender:
http://www.blender.org/

Languages:

GCC:
http://gcc.gnu.org/
Java:
http://java.sun.com/
Python:
http://www.python.org/

Mathematical Libraries:

NumPy,SciPy:
http://numpy.scipy.org/
Numerical Recipes:
http://www.nr.com/
GSL:
http://www.gnu.org/software/gsl/
Netlib:
http://www.netlib.org/

Plotting:

matplotlib, pylab:
http://matplotlib.sourceforge.net/
pylabline.py
pylabimage.py
DISLIN:
http://www.dislin.de/

Graphics Libraries:

PostScript
http://pages.cs.wisc.edu/~ghost/
psline.c
psimage.c
X Windows:
http://www.x.org/
xline.c
ximage.c
AWT/Swing:
http://java.sun.com/javase/6/docs/technotes/guides/awt/
http://java.sun.com/docs/books/tutorial/uiswing/
JavaLine.java
JavaLine.html
JavaImage.java
JavaImage.html
Tk:
http://www.tcl.tk/
http://www.pythonware.com/library/tkinter/introduction/
tkline.py
tkimage.py
OpenGL:
http://www.opengl.org/
http://www.opengl.org/resources/libraries/glut/
http://pyopengl.sourceforge.net/
glexample.c
glimage.c
glsurf.c
glimage.py
glsurf.py
VTK:
http://www.vtk.org/
vtkexample.py

Parallel Computing:

sockets:
http://docs.python.org/lib/module-socket.html
http://www.gnu.org/software/libc/manual/html_node/Sockets.html
http://java.sun.com/docs/books/tutorial/networking/sockets/
udpsnd.py
udprcv.py
MPI:
http://www-unix.mcs.anl.gov/mpi/
http://www-unix.mcs.anl.gov/mpi/mpich1/
http://mpi4py.scipy.org/
mpipi.c
benchmarks:
http://www.top500.org/
http://www.netlib.org/benchmark/hpl/
pi.c
pim.c
pi.py
pim.py

Multimedia:

SDL:
http://www.libsdl.org/
http://www.pygame.org/
sndline.py