CS208 Introduction to Computer Systems
Friday, 10 April 2026

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HEY JEFF: Sometime, you gotta explain that Makefile from the first assignment
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+ Quiz

+ Questions

+ UTF-8
- Unicode "codepoint" - the integer that represents one character
    U+0041 <-> A
    U+00E9 <-> é
    U+2191 <-> ↑
    U+1F60A <-> 😊

- U+03B1 --> byte sequence (the "encoding" of the character)

- E2 86 90 --> Unicode code point (which represents the character)

- You try it
    U+266D --> ?
    F0 9F 98 80 --> ?

- Why is UTF-8 like this? (Points in favor)
    - The only time you see a null byte is in the null character
    - No byte order problem
    - You can re-synchronize midstream if the byte stream gets corrupted for a while
    - Balance between 1-byte ASCII representation and variable-byte-count for
        higher codepoints (saves memory/disk space for lots of text)

- Who did this? Ken Thompson
    - Original author of Unix
    - Turing Award (with Dennis Ritchie) 1983
    - Turing Award Lecture 1983 -- explained a really nasty kind of virus
    - Plan 9 OS
    - Go language
    - UTF-8

+ BOM
- Byte order mark
- U+FEFF at start of file
+ Sunday's assignment
- ASCII toupper, tolower
- printing chars, and why it's so weird