Inkscape is famous free software alternative for vector drawing. Its a powerful tool to draw any sort of vector files.
Drawing a circle or disc is very much easy in Inkscape. We can draw it using create circle tool by pressing F5 key. Use CTRL key while drawing circle for better result. But creating a Ring or Annular disc is little bit confusing to beginners.
1. Draw a circle using create circle tool.
2. Press CTRL + D (which create a clone)
3. Pick another color for the clone.
4. while pressing CTRL + SHIFT reduce the size of clone!
5. Select both circles
6. From menu Path > Difference
7. Yes! Here is your disc!!!