CS208 Introduction to Computer Systems
Wednesday, 11 February 2026

+ Second half
- "Escape from the zoo" assignment
    - the gdb debugger
    - analyzing assembly code while it runs
- Buffer overflow assignment
    - insecure assembly language
    - how do functions get called? how does memory get used?
- Processes
    - how does a computer run multiple programs at once?
    - writing a small command shell
- Networks
    - clients and servers
    - a little bit of TCP/IP
- If time: memory hierarchies
    - caches
    - virtual memory
        (how does each process get to pretend it has
            2^64 bytes of memory?)

+ Today
- gdb lab (just C code)
- starting in on using gdb for assembly
- quick run-through of the zoo assignment

+ gdb lab recap
-Wall, -Werror, what are they for?
-g: put symbols into the executable to make it easier to debug
-Og: use the version of the "optimizer" that makes the code easy to debug
-o filename: "output" -- put the executable in filename
(gdb) x/40wx 0x7fffffffe980
    x means "examine memory"
    / means "here come some details"
    40 means "give me 40 chunks of memory"
    w means "make each chunk 4 bytes long"
    x means "show me the chunks in hexadecimal"


+ Lab