Published on June 29, 2025 KembaraXtra-Computer Science - Prefixes in Computing KembaraXtra - Computer Science - Prefixes in Computing 1. Introduction to Prefixes Purpose: Prefixes are used to represent large quantities of data (bits and bytes) in a concise and understandable way. SI Prefixes (Metric System): A standardized system of prefixes used to quantify various measurements, including data sizes. 2. Common SI Prefixes (Base 10) Prefix Name Prefix Symbol Value Base 10 English Word tera T 1,000,000,000,000 10¹² trillion giga G 1,000,000,000 10⁹ billion mega M 1,000,000 10⁶ million kilo k 1,000 10³ thousand centi c 0.01 10⁻² hundredth milli m 0.001 10⁻³ thousandth micro μ 0.000001 10⁻⁶ millionth nano n 0.000000001 10⁻⁹ billionth pico p 0.000000000001 10⁻¹² trillionth Usage: 3 billion bytes = 3GB; 4 thousand bits = 4kb Case Sensitivity: 'B' = Byte, 'b' = bit 3. Base 2 vs. Base 10 in Computing Bytes and Base 2: Computers internally operate in base 2 (binary). "1MB" Misconception: A file labeled as "1MB" is often 1,048,576 bytes (2²⁰), not exactly 1,000,000 bytes. 4. SI Prefix Meaning When Applied to Bytes (Base 2) Prefix Name Prefix Symbol Value Base 2 tera T 1,099,511,627,776 2⁴⁰ giga G 1,073,741,824 2³⁰ mega M 1,048,576 2²⁰ kilo k 1,024 2¹⁰ 5. Network Transfer Rates Advertisements: Internet speed is advertised in bits per second (base 10). Conversion: To find the equivalent in bytes per second, divide the advertised speed by 8 (bits per byte). Example: 50 Mbps internet = 50,000,000 bits/second = 6,250,000 bytes/second ≈ 6 MB/second. 6. IEEE 1541-2002 Prefixes for Binary Data Purpose: Introduced to remove ambiguity between base 10 and base 2 interpretations of SI prefixes. New Prefixes: kibi (Ki), mebi (Mi), gibi (Gi), tebi (Ti) are used to explicitly indicate powers of 2. Intended Usage: "kilobyte" (kB) should mean 1,000 bytes (base 10). "kibibyte" (KiB) should mean 1,024 bytes (base 2). 7. IEEE 1541-2002 Prefixes Table Prefix Name Prefix Symbol Value Base 2 tebi Ti 1,099,511,627,776 2⁴⁰ gibi Gi 1,073,741,824 2³⁰ mebi Mi 1,048,576 2²⁰ kibi Ki 1,024 2¹⁰ 8. Practical Implications and Common Misunderstandings Software Display: Most software uses the old SI prefixes (KB, MB, GB) but calculates sizes in base 2. Storage Device Marketing: Manufacturers advertise storage capacity using base 10. A "1TB" hard drive (1,000,000,000,000 bytes) will appear as roughly "931GB" when connected to a computer (1,000,000,000,000 bytes / 2³⁰).
