Source: https://guthlabs.ai/docs/instruments/raid-capacity-fault-tolerance-calculator/implementation/

instrument implementation / implementation-contract

# RAID Capacity & Fault-Tolerance Calculator implementation

A source-bound implementation contract for RAID Capacity & Fault-Tolerance Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t4-040

**Effect**: Computation or source lookup only

## Input and validation requirements

The zero-drive input causes a negative usable-capacity result and an undefined redundancy-overhead division by zero, so the instrument must reject it. The unit ambiguity can also produce materially different byte capacities unless TB versus TiB is made explicit.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "raid_level": "RAID0",
    "number_of_drives": 4,
    "drive_capacity": 2,
    "capacity_unit": "decimal TB"
  },
  "expected_outputs": {
    "usable_capacity": 8,
    "capacity_unit": "TB",
    "redundancy_overhead_percent": 0,
    "tolerated_simultaneous_failures": 0,
    "rebuild_risk_note": "No redundancy; any single drive failure loses the array. Vendor- and workload-specific rebuild/URE analysis is not performed."
  },
  "working": "Raw capacity = N×S = 4×2 = 8 TB. Usable capacity = 4×2 = 8 TB. Redundancy overhead = (8−8)/8×100 = 0/8×100 = 0%. RAID0 tolerated failures = 0."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/raid-capacity-fault-tolerance-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/raid-capacity-fault-tolerance-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/raid-capacity-fault-tolerance-calculator/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche4/tranche4-results.json`