{
  "slug": "lto-generations-capacity",
  "title": "LTO generations: native and compressed capacity and throughput, LTO-1 to LTO-10",
  "kind": "dataset",
  "summary": "Native and advertised compressed capacity, release year and maximum native throughput of LTO Ultrium generations 1 to 10 (11 rows, with the 30 TB and 40 TB LTO-10 cartridges), taken from the LTO Program pages for generations 8, 9 and 10 and the Wikipedia generations table for the rest, plus arithmetic: the hours to write one full cartridge at the maximum native rate and the capacity step from one generation to the next. Native capacity goes from 0.1 TB in LTO-1 to 40 TB in LTO-10, and the 40 TB cartridge takes 27.78 hours to fill at 400 MB/s. Two published speed figures do not match their own arithmetic and are flagged.",
  "license": "The capacities, ratios, years and speeds are public facts about LTO Ultrium products as published on lto.org and in the Wikipedia article on Linear Tape-Open. No page text is copied. The hours and ratio columns are arithmetic done here. LTO and Ultrium are trademarks of Hewlett Packard Enterprise, IBM and Quantum. Reuse is fine with attribution to the sources named below. This is a small derived table.",
  "licenseUrl": "https://en.wikipedia.org/wiki/Wikipedia:Copyrights",
  "sourceUrl": "https://www.lto.org/roadmap/",
  "accessed": "2026-10-10",
  "rowCount": 11,
  "columns": [
    {
      "name": "generation",
      "type": "string",
      "description": "LTO Ultrium generation, LTO-1 to LTO-10. LTO-7 Type M (M8) is an alternate format of an LTO-7 cartridge on LTO-8 drives and is not listed."
    },
    {
      "name": "cartridge",
      "type": "string",
      "description": "Cartridge variant: standard, or for LTO-10 the 30 TB and 40 TB cartridges."
    },
    {
      "name": "release_year",
      "type": "integer",
      "description": "Year of first availability as given in the Wikipedia generations table (LTO-10 30 TB May 2025, 40 TB January 2026)."
    },
    {
      "name": "native_capacity_tb",
      "type": "number",
      "description": "Native (uncompressed) capacity in decimal terabytes, as published."
    },
    {
      "name": "advertised_compressed_tb",
      "type": "number",
      "description": "Advertised capacity assuming the compression ratio in the next column, as published."
    },
    {
      "name": "compression_ratio",
      "type": "number",
      "description": "2 for LTO-1 to LTO-5 and 2.5 from LTO-6, as published. The build checks native times ratio equals the advertised figure."
    },
    {
      "name": "max_native_mb_s",
      "type": "integer",
      "description": "Maximum native data rate in megabytes per second between drive and tape, decimal units."
    },
    {
      "name": "hours_to_fill_at_max_native",
      "type": "number",
      "description": "native_capacity_tb * 1e6 / max_native_mb_s / 3600, hours to write one full cartridge at the maximum native rate. Computed here."
    },
    {
      "name": "native_capacity_vs_previous",
      "type": "number",
      "description": "native_capacity_tb divided by the native capacity of the previous generation, two decimals. For both LTO-10 rows the previous generation is LTO-9. Computed here."
    },
    {
      "name": "source",
      "type": "string",
      "description": "Where the numbers in the row come from."
    },
    {
      "name": "note",
      "type": "string",
      "description": "Differences between the sources, without commas."
    }
  ],
  "downloadPath": "/data/datasets/lto-generations-capacity.csv",
  "chartPath": "/data/datasets/lto-generations-capacity.svg",
  "citations": [
    {
      "id": "lto10",
      "title": "LTO-10: LTO Generation 10 Technology, lto.org",
      "url": "https://www.lto.org/lto-10/",
      "accessed": "2026-10-11"
    },
    {
      "id": "lto9",
      "title": "LTO-9 page, lto.org",
      "url": "https://www.lto.org/lto-9/",
      "accessed": "2026-10-11"
    },
    {
      "id": "lto8",
      "title": "What is LTO-8 technology, lto.org",
      "url": "https://www.lto.org/lto-8/",
      "accessed": "2026-10-11"
    },
    {
      "id": "roadmap",
      "title": "Roadmap, lto.org",
      "url": "https://www.lto.org/roadmap/",
      "accessed": "2026-10-11"
    },
    {
      "id": "wp-lto",
      "title": "Linear Tape-Open, Wikipedia: generations table",
      "url": "https://en.wikipedia.org/wiki/Linear_Tape-Open",
      "accessed": "2026-10-11"
    }
  ]
}