CS208 Introduction to Computer Systems
Monday, 22 May 2023

+ Questions about bytes
- How many bits are in a byte?
    8
- How many different bit patterns could a byte store?
    00000000...11111111 : 2^8 = 256
- How many hexadecimal digits are required to specify the value of a byte?
    2

- Suppose you enter "ABCD" in a file something.txt and save it.
    - What Unix command can you use to see the contents of this file as text?
        cat something.txt
    - What Unix command can you use to see the contents of this file as
        individual bytes expressed in hexadecimal?
        hexdump -C something.txt
    - What output does that second command produce?
        (are you seeing something like 41 42 43 44 0a?)
        yes

- Now enter "41 42 43 44 0a" in something.txt
    - Use that second Unix command above to look at the new contents
        of something.txt

- cat something.txt | hex2raw > something-else.txt

    - What happened?

+ ...