The book’s vocabulary
Terms with
working meanings.
51 terms from the glossaries of both volumes. Every term has its own page: the book’s working definition, the chapters and sections where the term is discussed, and the posts that take it up.
terms.json · terms.jsonld · stable IDs like https://withoutsurprise.com/vocab/reservation
Accepted task
A task that met the business's acceptance criteria for its task class, not merely a completed request or a response that arrived on time.
Attribution
Connecting spend or consumption to the workload, team, customer, or decision that caused it.
Baseline forecast
A forecast made with an explicitly defined starting method and information set, such as a seasonal-naive forecast, which repeats the latest observation from…
Basis risk
The gap between what a hedge's price index measures and what we pay for the hardware, region, terms, and dates we actually need.
Budget
An authorized financial boundary or plan.
Capability
What the business and its technology need to be able to do: features, reliability and resilience, customer experience, and operational outcomes.
Capacity
The work a system can support in a stated interval under stated workload, quality, configuration, and operating conditions.
Cohort
Workloads grouped for a stated planning reason, with maintained membership, an owner, and a way to detect exceptions.
Commitment
A commercial or operational promise whose parties, scope, and term must be stated.
Coordinated omission
A load-testing error in which a generator that waits for each response stops sending the requests that would have suffered most during a stall, so measured l…
Cost
The money and obligations a system creates while it runs, whether or not anyone has attributed them yet.
CPU-bound
Limited materially by available processing capacity under the observed conditions.
Data-bound
In this book, work whose limiting behavior depends materially on data access, movement, layout, state, or coordination.
Demand intelligence
Information about future business activity, kept with its source, evidence date, assumptions, timing, dependencies, and a condition for review; also the prac…
Double bubble
The temporary overlap of old and replacement environments during a transition.
Elasticity
The ability to add and release resources as demand changes.
Evidence date
The date information became available to the planners, as distinct from the date of the activity it describes.
Failure group
Resources assumed to become unavailable together in a specified scenario.
Fixed cost
Cost that does not change with the relevant activity over a specified range and period.
Forecast
An estimate of future demand under stated assumptions, with an as-of date showing what was known when it was made.
Headroom
The deliberately unused portion of capacity, bought on purpose to absorb demand and failure.
Lead time
The interval between deciding to obtain supply and its readiness date, when it is qualified and usable for the stated work.
Little's law
In a stable system, the average number of items present equals their arrival rate times the average time each spends there, $L = \lambda W$.
Long tail
The many smaller consumers in a ranked portfolio.
Marginal cost
The change in cost associated with an additional unit or a specified change in work.
Metered cost
Cost calculated from counted consumption, such as requests, worker-hours, GB-months, or tokens, and a pricing rule.
Obligation
What the organization has promised to pay, including promises that outlast the reason for making them.
Opportunity cost
The value of the best alternative displaced by a choice.
Prediction interval
A range derived from a forecast distribution under specified assumptions.
Provisioned throughput
Model-serving capacity held for a deployment and billed by the hour, busy or idle.
Qualified capacity
Resources demonstrated to perform the intended work under the relevant conditions.
Quota
A limit on permitted resource allocation or consumption within a defined scope.
Reconciliation
Making related views add up under consistent boundaries.
Request
A statement of what someone wants, which begins investigation or negotiation.
Reservation
A commercial arrangement whose effect depends on its terms: a price discount, a hold on specified capacity, or both.
Reserve
Capacity held for an identified purpose, with stated readiness, authority to use or release it, and review conditions.
Rolling-origin evaluation
Evaluating forecasts made from successive past starting points, each a forecast origin, using only information available at that origin.
Saving
In this book, a reduced expenditure: an actual obligation or charge that fell within the stated boundary.
Savings plan
A commitment to spend a fixed amount per hour for one or three years in exchange for discounted rates on eligible usage.
Scenario
A stated combination of conditions used to examine consequences and choices.
Shadow price
In a linear model, the local value of relaxing a constraint by one unit.
Showback and chargeback
Showback makes attributed cost visible to the groups responsible for it; chargeback assigns those costs to budgets or accounting structures.
SKU
Stock-keeping unit, borrowed from retail inventory: one sellable configuration of a service in a provider's catalog, with its size, features, and price.
Spillover
Sending requests that exceed provisioned capacity to shared pay-as-you-go capacity, billed at that rate.
Systems that drive consumption
The customers, product decisions, architecture, recovery requirements, migrations, and AI behavior that produce the consumption a bill and a capacity chart r…
Take-or-pay
A commitment charged for the committed quantity whether or not it is used.
Target
Something the organization intends to achieve.
Token budget
An allowance of specified token categories over a stated period.
Token economics (Tokenomics)
The relationship among AI workload design, consumption, supplied capacity, cost, and accepted work.
Unit economics
The cost of one completed unit of useful work, rather than of a machine-hour, with a stated cost boundary and quality condition.
Usable supply
Capacity qualified and available at the required place and time, after the constraints relevant to the decision are applied.