Ruankao System Analyst (Senior) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Amdahl's law

Speedup is capped by the serial fraction of a workload: speedup = 1 / ((1-f) + f/s). Adding processors yields diminishing returns once the parallel portion saturates.

Pipeline hazard

A condition preventing the next instruction from executing in the next clock cycle. Structural hazards are resource conflicts, data hazards are dependencies, and control hazards arise from branches.

RAID 5

Block-level striping with parity distributed across all member disks. It survives one disk failure, offers good read performance, and requires at least three disks.

Little's law

The average number of items in a system equals arrival rate multiplied by average time in system (L = λW). It applies to queues, thread pools, and work-in-progress limits.

COCOMO II

A parametric software effort estimation model. Effort is derived from project size adjusted by scale factors and cost drivers, producing person-months for planning.

Functional cohesion

The strongest form of cohesion, where every element of a module contributes to one single, well-defined task. It is preferred over coincidental or logical cohesion.

Boundary value analysis

A black-box test technique selecting inputs at and just outside the edges of valid ranges, because defects cluster at boundaries rather than in the middle of ranges.

Technical debt

A metaphor for deferred design or code rework. It delivers short-term speed but accrues interest as higher maintenance cost and reduced changeability over time.

MoSCoW prioritization

A requirements ranking method: Must have, Should have, Could have, Won't have this time. Must items define the minimum releasable scope.

Non-functional requirement

A quality attribute or constraint on how a system performs its functions, such as response time, availability, security, or regulatory compliance. It must be measurable.

Use case

A description of interactions between an actor and a system to achieve a goal, comprising a main success scenario plus alternate and exception flows.

Traceability matrix

A table mapping each requirement to its design elements, code modules, and test cases. It supports impact analysis when requirements change and demonstrates coverage.

CAP theorem

In a distributed data store, a network partition forces a choice between consistency and availability. Systems are classified as CP or AP accordingly.

Dependency inversion principle

High-level modules should not depend on low-level modules; both should depend on abstractions. This reduces coupling and improves substitutability and testability.

Idempotent operation

An operation whose repeated execution produces the same result as a single execution. It is essential for safe retries under at-least-once message delivery.

Microservices architecture

A style decomposing an application into independently deployable services owning their data. It gains team autonomy and scaling but adds distributed complexity and consistency challenges.

Third normal form

A relation in second normal form with no transitive dependency of a non-key attribute on the primary key. It removes redundancy caused by non-key determinants.

ACID properties

Atomicity, Consistency, Isolation, and Durability. These guarantees define reliable transactional behavior in relational database systems under concurrency and failure.

Star schema

A dimensional warehouse model with a central fact table referencing denormalized dimension tables. It simplifies queries and improves OLAP read performance.

Covering index

An index containing all columns referenced by a query, allowing the database to answer the query from the index alone without reading the base table.

TLS handshake

The protocol exchange establishing a secure session: negotiating cipher suites, authenticating the server via certificate, and deriving shared session keys.

Defense in depth

A security strategy layering independent controls across network, host, application, and data, so failure of one control does not compromise the whole system.

Non-repudiation

A property ensuring a party cannot credibly deny having performed an action, typically achieved with digital signatures and audit logs.

Critical path

The longest sequence of dependent activities through a project network. It determines the minimum project duration and has zero total float.

Cost performance index

Earned value divided by actual cost (CPI = EV / AC). A value below one indicates the project is spending more than the work earned.

Branch coverage

A test adequacy metric requiring every decision outcome, true and false, to be exercised at least once. It is stronger than statement coverage.

Quality assurance versus control

Assurance is process-oriented and preventive, improving how work is done. Control is product-oriented and detective, inspecting and testing outputs against requirements.

Elasticity

The ability of a system to automatically provision and release resources in response to demand. It differs from scalability, which is the capacity to handle growth.

Container

A lightweight runtime unit packaging an application with its dependencies while sharing the host kernel. It starts faster than a virtual machine but isolates less strongly.

Model drift

Degradation of a deployed machine learning model's accuracy as live data distributions diverge from training data. It requires continuous monitoring and retraining.

Shall versus should

In requirements writing, 'shall' denotes a mandatory obligation, 'should' a recommendation, and 'may' an option. Consistent modal verbs prevent contractual ambiguity.

Active voice

A sentence construction where the subject performs the action. It is preferred in technical writing for clarity, directness, and shorter sentences.