units of data storage Flashcards
(20 cards)
What is the order of data storage units from smallest to largest?
1 bit
1 nibble = 4 bits
1 byte = 8 bits
1 kilobyte = 1000 bytes
1 megabyte = 1000 kilobytes
1 gigabyte = 1000 megabytes
1 terabyte = 1000 gigabytes
1 petabyte = 1000 terabytes
Why must data be converted into binary by a computer for processing?
When any key on a keyboard is pressed, it must be converted into a binary number so it can be processed by the computer and the typed character can appear on the screen.
How do you convert decimal to binary?
Use place values (128, 64, 32, 16, 8, 4, 2, 1). Example: 24 = 16 + 8 → 00011000.
What happens in an overflow error during binary addition?
If the result takes more bits than allocated (e.g., 9 bits in an 8-bit system), an overflow occurs. Can lead to loss of data & accuracy
How do binary shifts work?
Multiply by 2: Shift left (add a 0).
Divide by 2: Shift right (remove last digit).
Convert hexadecimal 2B to decimal.
(2 × 16) + (11 × 1) = 43.
Convert decimal 60 to hexadecimal.
60 ÷ 16 = 3 r 12 → C
3 ÷ 16 = 0 r 3 → 3
Result: 3C.
Convert binary 10011100 to hexadecimal.
Split into nibbles: 1001 (9) + 1100 (C) → 9C.
Convert hexadecimal A7 to binary.
A = 1010, 7 = 0111 → 10100111.
What is a character set?
A collection of all the different characters used to represent text in a computer system.
What is ASCII?
Uses 8-bit codes (256 characters) but cannot represent multiple languages (e.g., Greek).
What is Unicode?
A character set using up to 32 bits (billions of codes), supporting multiple languages via code pages.
What are digital images made of
Pixels
Define color depth and resolution. What does increasing these factors do?
Color depth: Bits per pixel (e.g., 8 bits = 256 colors).
Resolution: Pixels per unit (e.g., ppi).
Increasing these factors increases the quality of the image but also the file size
Calculate image file size.
Height (pixels) × Width (pixels) × Color depth (bits).
What is metadata? Give 3 examples
Data about data
E.g: date created, file size, author, resolution, width/height
Define sample rate and resolution. What does increasing these factors do
Sample rate: Samples per second (kHz).
Resolution: Bits per sample.
Increasing these factors increases the playback quality but also the file size
Calculate sound file size.
Sample rate × Sample resolution × Duration (seconds).
What is lossless compression?
Reduces file size without losing data (e.g., for word docs).
What is lossy compression?
Reduces size by removing unrecoverable data (e.g., for images/audio).
