Anatomy of a Program in Memory

Submit more articles like this one and less Web 2.0 gossip please.

Really great article and blog. > You can examine binary images using the nm and objdump commands to display symbols, their addresses, segments, and so on. You can also use my new tool Bloaty McBloatface (https://github.com/google/bloaty). Check out the -v option especially, which will dump a memory map of both the file domain and the VM address domain: $ ./bloaty `which ls` -v -d segments FILE MAP: [0, 19d44] LOAD [RX], LOAD [RX] [19d44, 19df0] [None], [Unmapped] [19df0, 1a5f4] LOAD…

This may not be entirely related, but I've been building an open-source kernel in z80 assembly for three and a half years now: https://github.com/KnightOS/kernel I might chime in with a perspective of someone working on 70s hardware without memory protection, ring modes, or enough RAM to page it around. In my system, all processes run as root (since we can't stop them from doing so on a z80), and share one big memory block. The kernel takes up the first…

All the diagrams that show the stack "above" the heap may be an example of a widespread "UNIX-ism"; and indeed, there are many questions on StackOverflow and the like from semi-confused beginners wondering why they see heap allocations having higher addresses than ones on the stack. In Windows, stacks are usually very low in memory, even below the process image itself (which is normally loaded at 4MB[1]), and heaps are above. Of course, if you have many threads, stack and…