How we price the comparison.

Complete XPNTL Archive systems, each including the computer that runs it, its staging tier, the tape hardware, tape media and our software. They are named by drive count, not by size of business:

• Archive Deskside with Solo Pro (AS-1): one LTO-9 desktop drive on a Mac mini, with a 2-bay RAID as the staging tier.
• Archive Rack 1 with Library Pro (AL-1): a 40-slot library with one LTO-9 drive, run by a rack server with SSD staging.
• Archive Rack 2 with Library Pro (AL-2): the same library with two drives and more SSD staging.
• A larger server with RAID staging: coming soon.

Against them: an Enterprise Disk Appliance (object storage, erasure coded) and a Public Cloud Archive Tier (the lowest-cost of four providers), both from the LTO Show storage cost model, with its own published methodology. We compare categories, not vendors.

Every column prices the same job: the same archive, kept for the same term, one copy, list prices for new equipment, and the same rates for power, space and carbon. The XPNTL columns can also hold that copy physically offline. The lead figure is cost per TB over the term: total cost divided by the TB stored at the end of it.

New equipment at published list price, everywhere. Store feeds use the compare-at (list) price when a store shows one, never a sale price. Reseller prices use CDW's advertised price, or Insight's list price when CDW has none, never a struck-through reference price. Manufacturer stores (Apple, MagStor, TerraMaster) count as list. Used, refurbished, recertified and open-box prices are never used.

Tape media is priced from LTOworld, the same feed the LTO Show model uses. XPNTL software is priced from our own license server, the same prices as our pricing page. Disk and cloud are priced by the LTO Show model on the same list-price basis.

Each line of each build is defined by a spec, not a part number: what it must be, not which model it is today. Configurations change often, so the part that meets a spec changes too.

• Daily: every store feed and our license server are read again. A price change on the same part within 15% applies automatically.
• Weekly: a research agent checks every hand-read price. It confirms the part is still sold new at list price and still meets its spec. If it isn't, it finds the best current product that does, from any brand, with the page it came from.
• Always reviewed: a replacement part, or a price move of more than 15%, is held for a person to approve. Until then the page keeps the last approved price.
• Dated: every price on the calculator shows where it came from and when it was checked. Hand-read prices older than 90 days are flagged for a fresh check.

Hardware: quantity times list price for every line.

Tape media: enough LTO-9 cartridges (18 TB native) for the archive at the end of the term, and at least 40 for the rack systems. It scales with archive size, so at 720 TB every system holds the same 40 cartridges.

Larger archives: the calculator takes archives of up to 50,000 TB today. The rack systems grow with the archive: they get enough LTO-9 drives to restore 10% of the archive in 7 days at 400 MB/s per drive, counting 92 seconds per cartridge to load it, find the data and unload it, and library slots for that 10%, in expansion modules of 40 slots (up to 640 slots per library). The other cartridges wait on a shelf, where they draw no power and have no network path. Added drives, expansion modules and the power supplies they need are priced at MagStor list price from the MagStor PetaByte Machine configurator, which also sets the per-module limits; the power drawn by an expansion module is the configurator's estimate. The staging tier grows with the tape drives. It starts with two 7.68 TB SSDs for each tape drive, up to six SSDs in the server. Each tape drive added after that gets two 10 TB hard drives in a disk enclosure beside the server, enough to keep it streaming. Restores also pass through the backup server and its 10 GbE link, which the page prices as one server and one link, so at large archives the 7-day restore needs a faster server path, sized by quote. Archive Deskside is sized for archives of up to 5,000 TB at the end of the term; above that, the calculator shows it as not sized for the archive.

Software: the XPNTL edition each system includes, one license per computer, one time. With the box ticked, XPNTL Sentry Pro is added for every year after the first, which keeps software updates coming. It is optional: the software keeps working and restores always work without it.

Hardware maintenance: 7% of hardware cost per year, the same rate the LTO Show model applies to tape and disk.

Energy: power draw × 8,760 hours × years × the model's electricity rate, times the model's data-center overhead (PUE) for rack builds. The desktop build sits on a desk, so it carries no data-center overhead.

Sustainability charge: energy use × the model's grid carbon factor × its carbon price.

Floor space: the library build uses the model's floor-space charge for the same library. The desktop build uses none.

Staff time is left out of every total, as in the LTO Show model, and shown separately. The model applies the same rate to every on-premises option.

We use the manufacturer's published figure where there is one. Where none is published, we use a stated estimate for typical operating power, marked below, until the weekly check finds a published number.

Shipping, sales tax, racks, network switches, cabling beyond what a line lists, installation, and your own labor beyond the model's staff rate. For disk and cloud, the LTO Show model covers the storage itself and leaves out backup software and media servers.

The disk and cloud figures and the shared rates come from the storage cost model published by LTO Show, with its methodology and sources public. LTO Show and XPNTL Archive share an owner. The XPNTL builds, their specs and prices are ours, and every one of them is shown in full on the calculator.