Unit 1 Flashcards
what monoalphabetic cipher do computers use?
ASCII (American Standard Code for Info Interchange)
in ASCII, how many bytes is in 1 character?
1 byte
how many bits are in a byte?
8 bits of 1’s or 0’s
how many diff things can 1 byte represent?
max byte is 1111 1111 = 255 + “zero” = 256 possibilities (2^8)
is ASCII enough?
for English, it’s enough (A-Z, a-z, punctuation). for Chinese (>10,000 characters), Syrillic, Japanese, and Korean however, it’s not enough.
how do we create more possibilities for each character?
add more bytes
how many possibilities does 2 bytes have?
2 bytes = 16 bits; 2^16 = 65,536 possibilities (1111 1111 1111 1111 + “zero”)
what code do modern documents use?
Unicode
what does Unicode stand for?
Universal Code
how many bytes for each character does Unicode have?
4 bytes = 32 bits; 2^32 = around 4 billion possibilites
bit map
black and white representation of something using bits as pixels
megabyte
1 million bytes
how can a large pic be more than 1 million bytes?
color, brightness, hue, etc.
how do u add color into a picture?
1 pixel = 3 bytes and each byte represents a primary color (red, green, or blue). in each byte, there are 256 possibilities of red, green, and blue which you can mix to create a wide array of colors.
how come the primary colors in computers are different than normal primary colors?
Computers use light instead of paint.
