Gigabyte to Petabyte

Hard drive manufacturers measure 1 TB as 1,000,000,000,000 bytes (decimal). Windows displays storage in gibibytes (binary) but historically labelled them as "GB" — so 1,000,000,000,000 bytes ÷ 1,073,741,824 ≈ 931 GiB, which Windows displayed as "931 GB". macOS (since 10.6) correctly reports the same drive as "1 TB" using decimal GB. The drive is not lying; the OS was using a binary unit with a decimal label.

8 GB RAM is the current minimum for gaming; 16 GB is the recommended standard for most modern games at 1080p and 1440p; 32 GB benefits heavily multitasking systems or games with large open worlds. Memory-intensive tasks like video editing, 3D rendering, and running large language models locally typically require 32–64 GB or more.

A 4K movie in H.264 or H.265 encoding is typically 50–100 GB on Blu-ray; streaming services compress aggressively to 15–25 GB for 4K HDR content. Netflix's 4K streams average about 7 GB per hour; the downloaded version via the Netflix app for offline viewing is roughly 3–6 GB per hour at high quality settings.

1 GB of mobile data supports roughly: 2–3 hours of music streaming, 1 hour of HD video streaming, 2–3 hours of web browsing, or 30–60 minutes of video calling. Social media apps with autoplay video are heavy consumers — TikTok and Instagram Reels can use 300–600 MB per hour of active use.

AI model sizes vary enormously. GPT-2 (2019) is about 1.5 GB; Llama 2 7B is roughly 13 GB in float16 precision; Llama 2 70B is about 130 GB. GPT-4-class models are estimated at 500+ GB. Quantised (compressed) versions are smaller: a 4-bit quantised 7B model fits in about 4 GB, runnable on a modern laptop. Training requires far more — the training dataset, gradients, and optimizer states for a 70B model can occupy 1–2 TB of GPU memory across a cluster. The trend toward larger models is driving consumer GPU memory from 8 GB to 16–24 GB as a baseline for local AI inference.

1 petabyte (PB) = 1,000 terabytes (TB) in the SI decimal system. In the binary IEC system, 1 pebibyte (PiB) = 1,024 tebibytes (TiB) = 1,125,899,906,842,624 bytes. The distinction matters for enterprise storage procurement: a petabyte of raw disk capacity appears as about 909 TiB in an OS reporting binary units.

Petabyte-scale storage is common at: social media platforms (Facebook/Meta stores over 100 PB of photos alone), streaming services (Netflix's content library is estimated at 100+ PB), government agencies (US NSA, CERN particle physics data), genomic research institutions, and large financial exchanges storing tick-level trading data. Major cloud providers (AWS, Azure, GCP) collectively store zettabytes.

In 2024, cloud storage costs roughly $20–25 per TB per month (S3 standard tier), making 1 PB approximately $20,000–$25,000/month. Raw enterprise disk hardware for 1 PB runs about $20,000–$50,000 upfront (at $20–50 per TB for high-density drives), plus ongoing power, cooling, and management overhead. Tape-based archival storage is considerably cheaper at $2–5 per TB.

YouTube users upload approximately 500 hours of video per minute, or 720,000 hours per day. At an average compressed size of 1–2 GB per hour of HD video, that equates to roughly 720–1,440 TB (0.7–1.4 PB) of new video data per day — before YouTube re-encodes into multiple formats and quality levels, which multiplies storage requirements several-fold.

The SI prefix hierarchy above petabyte: exabyte (EB, 10¹⁸ bytes), zettabyte (ZB, 10²¹ bytes), yottabyte (YB, 10²⁴ bytes), ronnabyte (RB, 10²⁷ bytes), and quettabyte (QB, 10³⁰ bytes) — the last two added by the BIPM in 2022. Current global data storage is estimated in the hundreds of exabytes; no single organisation approaches yottabyte scale.