1. What is core dump?

Raises when accessing an unassigned memory location
accessing a null pointer

2. How to debug the core dump?

gdb... backtrace
gdb filename...

3. How debugger works internally?

Whenever we compile with -g option, it will create a symbol
table, and according that table for each function and line
it will call ptrace ...and do the things

4. Explain What bug tracking tools you have used? Have you used any free tools?

Bugzilla JIRA footprint. Bugzilla is free. BugTrack is