Applied Information Technology Engineer Examination key terms

A measure of processor speed expressing how many millions of instructions a CPU can execute per second. It is only comparable across machines with the same instruction set and is a rough, workload-dependent benchmark.

Cycles per instruction: the average number of clock cycles a processor spends on each instruction. Lower values mean more work per cycle; execution time equals instruction count times CPI divided by clock frequency.

The basic time interval of a processor's clock, whose reciprocal is the clock frequency. It bounds how quickly pipeline stages advance and determines the granularity of CPU timing.

A technique that overlaps execution of multiple instructions by splitting work into stages, so several instructions are in flight at once. It raises throughput but introduces hazards and branch penalties.

A small, fast memory placed between the CPU and main memory that holds recently or frequently used data. It exploits locality of reference to hide the gap between processor and memory speeds.

The tendency of programs to access a small set of addresses repeatedly (temporal locality) or nearby addresses in sequence (spatial locality). Caches and virtual memory depend on this property for their effectiveness.

A mechanism giving each process a private logical address space mapped to physical memory by hardware and the OS. It enables larger programs than RAM, isolation between processes, and demand paging.

A memory management scheme dividing logical and physical memory into fixed-size blocks called pages and frames. A page table translates addresses, and a page fault loads a missing page from secondary storage.

Translation lookaside buffer: a small associative cache of recent page-table entries inside the MMU. A TLB hit avoids a memory access for address translation; a miss triggers a page-table walk.

A way of combining several disk drives for performance, capacity, or fault tolerance. Common levels are 0 (striping), 1 (mirroring), 5 (distributed parity), and 6 (double parity).

Mean time between failures: the average operating time expected before a repairable system fails. Combined with mean time to repair it yields availability, and it is used in reliability design of redundant systems.

Four guarantees for database transactions: atomicity (all or nothing), consistency (valid state transitions), isolation (concurrent transactions do not interfere), and durability (committed changes survive failure).

Concurrency control that prevents transactions from interfering, typically by locking. It avoids lost updates and dirty reads at the cost of waiting and possible deadlock.

A state where two or more processes each hold a resource the other needs and none can proceed. It requires mutual exclusion, hold-and-wait, no preemption, and circular wait to occur.

A synchronization variable with an integer value and atomic wait and signal operations, used to control access to shared resources or to signal between processes. A binary semaphore acts as a mutex.

A distributed commit protocol in which a coordinator first asks all participants to prepare, then tells them to commit or abort. It ensures atomic commit but can block if the coordinator fails.

The process of structuring relational tables to remove redundancy and update anomalies, using functional dependencies. First through third normal forms, and Boyce-Codd normal form, are the usual targets.

An encryption scheme using a key pair: a public key for encryption or signature verification and a private key for decryption or signing. It solves key distribution but is slower than symmetric ciphers.

A value computed over a message with a sender's private key that anyone can verify with the public key. It provides authenticity, integrity, and non-repudiation, but not confidentiality by itself.

A one-way function mapping arbitrary input to a fixed-length digest, used for integrity checks, password storage, and signatures. Collision resistance is essential for security use.

A scheme that encrypts data with a fast symmetric key and protects that key with public key cryptography. TLS and S/MIME use this combination to get both speed and easy key exchange.

An attack that inserts crafted SQL fragments through unvalidated input to alter queries and read or modify data. Placeholders, parameterized queries, and input validation are the standard defenses.

A web attack that injects malicious script into pages viewed by other users, stealing sessions or credentials. Output encoding and content security policy are primary mitigations.

The protocol suite underlying the Internet. IP handles addressing and best-effort routing; TCP adds reliable, ordered, connection-oriented delivery with flow and congestion control.

A bit pattern that separates the network portion of an IP address from the host portion, enabling routing within and between subnets. Prefix length notation such as /24 expresses the same information.

The domain name system resolves human-readable names to IP addresses through a distributed hierarchy of name servers. It uses caching and record types such as A, AAAA, MX, and CNAME.

A protocol that automatically assigns IP addresses, subnet masks, gateways, and DNS servers to hosts. It reduces configuration errors and centralizes address pool management.

Unified Modeling Language: a standard notation for describing software structure and behavior. Common diagrams include class, sequence, activity, state machine, and use case diagrams.

A reusable solution to a recurring software design problem, described by intent, structure, and consequences. Examples include Factory, Observer, and Strategy.

Defining and controlling what work is included in a project. It covers requirements, work breakdown structure creation, scope verification, and change control to prevent creep.

Work breakdown structure: a hierarchical decomposition of project deliverables into manageable work packages. It is the basis for estimating cost and duration and for assigning responsibility.

A technique comparing planned value, earned value, and actual cost to measure schedule and cost performance. Indexes and variances reveal whether a project is ahead or behind.

A scheduling technique identifying the longest chain of dependent activities, which determines the shortest possible project duration. Any delay on the critical path delays the whole project.

A widely adopted framework of best practices for IT service management. It describes service strategy, design, transition, operation, and continual improvement, and is used to structure service desks and SLAs.

Service level agreement: a contract defining the service levels a provider must meet, such as availability and response time, and the consequences of missing them.

The IT service management process that restores normal service as quickly as possible after a disruption, distinct from problem management, which seeks root causes.

A performance management framework that tracks financial, customer, internal process, and learning perspectives. It links measures to strategy rather than relying on financial results alone.

A strategic assessment of an organization's internal strengths and weaknesses and external opportunities and threats. It is used to shape strategy but does not by itself prioritize actions.

Critical success factor: a small number of areas in which satisfactory results are essential for a strategy or project to succeed. CSFs guide where measurement and attention should focus.

Key performance indicator: a quantified measure chosen to track progress toward a critical success factor. Good KPIs are specific, measurable, and tied to decisions.

Return on investment: the ratio of benefit gained to cost invested, often expressed as a percentage. It is used to compare IT investment options, though intangible benefits are hard to quantify.

Net present value: the sum of future cash flows discounted to today's value, minus the initial investment. A positive NPV indicates an investment adds value.

Total cost of ownership: the full lifetime cost of an IT asset or system, including acquisition, operation, maintenance, support, and disposal. It exposes costs hidden by purchase price alone.

Conformity with laws, regulations, contracts, and internal policies that apply to an organization's activities and data. It typically requires documented controls, audits, and evidence of adherence.

Policies and procedures an organization establishes to safeguard assets, ensure reliable reporting, and promote operational efficiency. Segregation of duties and approval workflows are typical controls.

Information security management system: the set of policies, processes, and controls an organization uses to manage information risk. ISO/IEC 27001 defines requirements for establishing and certifying one.

The process of identifying threats and vulnerabilities, then estimating the likelihood and impact of harm to determine how risks should be treated, accepted, transferred, or avoided.

Legally protected creations of the mind, including patents, copyrights, trademarks, and trade secrets. Each right differs in what it protects, how long it lasts, and how it is obtained.