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OSI (CS6640): Week02a, C in egos-2k+ (homepage, lottery) - Coggle Diagram

- - - - easy to write incorrect code
      - easy to write code that has security vulnerabilities
      - using high-level language to implement OS?
        
        using Go: Biscuit
        
        using Rust: Theseus
  - - - hexadecimal numbers
        
        Q: are these valid hex numbers?
        
        0xbebebe
        
        0x123456789abcdef
        
        0xdeadbeef
        
        binary vs. hex
        
        0000 == 0x0
        
        1111 == 0xf
        
        why "0x" for hex?
        
        see here
        
        Q: show $misa using hex; what does this CPU provide?
        
        misa register
        
        example
      - Digression: self-respecting CS person must memorize powers of 2
        
        When is programmer's day?
      - Q: why bit has only two values?
        
        does it work for a machine with bits representing three values?
        
        Yes! Ternary machines; somewhat "optimal"
      - bit & byte
        
        Q: How many bit patterns can a group of 2 bits have?
        Q: How many bit patterns can a group of 3 bits have?
        Q: How many bit patterns can a group of N bits have?
    - - an executable program = a binary file
      - an executing program = CPU registers + some chunks of memory
      - instructions
      - data
        
        text file
        
        web page
        
        picture
        
        video
      - Q: In egos-2k+, an int is 4B.
        How does 0xdeadbeef look like in memory?
  - - - a pointer =
        a memory address