> okay, i tried. so why are globals bad and what problems > do they solve?
now, my OS theory may be a bit rusty -- pls correct me where i'm wrong, but from what i recall, one reason they're bad is because they take up "unneeded" amount of memory. in a traditional stack model -- think C, assembly, and how binaries are loaded into the OS for execution: you have the TEXT section, which consists of the executable code, the DATA section (sometimes divided up into 2 separate areas, for zero- and nonzero-initialized/BSS data) for static variables, global variables, etc., and the STACK and HEAP, as in this diagram (drawn upside-down): http://www.informit.com/content/images/chap3_0131429647/elementLinks/03fig01.jpg the STACK is for tracking function calls (plus local variables including parameters) while all dynamically-allocated memory comes from the HEAP. by increasing the size of your DATA section for globals, it reduces the overall number of stack frames (function calls) you can chain together, and likewise, you reduce the total amount of memory that can be dynamically-allocated. the STACK grows upward while the HEAP grows downward, and memory issues occur when the twain meet. if you have tons of globals, it increases the chance of these types of collisions. this GDB tutorial page is also useful in understanding these concepts: http://www.dirac.org/linux/gdb/02a-Memory_Layout_And_The_Stack.php the way it relates to Python is that Python is (of course) written in C, and unless you're using the Stackless version of Python, each Python function call results in one Python stack frame which results in one C stack frame. hope this helps! -- wesley - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - "Core Python Programming", Prentice Hall, (c)2007,2001 http://corepython.com wesley.j.chun :: wescpy-at-gmail.com python training and technical consulting cyberweb.consulting : silicon valley, ca http://cyberwebconsulting.com _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
