Concept 1 · free preview
Bits, bytes, storage units and binary
Understand
A computer stores all data in binary (0 and 1). One digit (0 or 1) = 1 bit. 8 bits make 1 byte — roughly one character.
| Unit | Equals |
|---|---|
| 1 nibble | 4 bits |
| 1 byte | 8 bits |
| 1 KB (kilobyte) | 1024 bytes |
| 1 MB (megabyte) | 1024 KB |
| 1 GB (gigabyte) | 1024 MB |
| 1 TB (terabyte) | 1024 GB |
Rule
Increasing order: bit < nibble < byte < KB < MB < GB < TB. Each unit is 1024 times the previous one (2 to the power 10).
Example
2 GB = 2 × 1024 = 2048 MB.
13 in binary: 13 = 8 + 4 + 1 → places 8, 4, 2, 1 get 1, 1, 0, 1 → 1101.
Check: 1011 = 8 + 2 + 1 = 11; 1110 = 14; 1001 = 9.
Remember
Binary place values from the right: 1, 2, 4, 8, 16, 32 … Break the number into a sum of these powers.
Common mistake
Mixing up 1000 and 1024. Computer memory and exam questions usually use 1024 (2 to the power 10); in the decimal (SI) system 1 GB = 1000 MB, which disk and pen-drive makers print. Use the relation the question gives; if none is given, use 1024.
Check yourself
How many bits make one byte?