Fundamental Information Technology Engineer Examination key terms

A base-2 number system using only the digits 0 and 1, where each position represents a power of 2. Computers use it because circuits have two stable states.

A base-16 number system using digits 0–9 and letters A–F. It is used as a compact shorthand for binary data because each hex digit maps exactly to four bits.

A method of representing negative integers by inverting all bits of the positive value and adding 1. It lets the same adder circuit handle subtraction and avoids a separate negative zero.

A condition where a computed result exceeds the range representable in the fixed number of bits allocated, so the stored value wraps or becomes incorrect. Signed and unsigned ranges differ.

A number format expressing values as a sign, exponent, and mantissa, allowing very large and very small magnitudes. Precision depends on the number of mantissa bits, and rounding errors can accumulate.

The difference introduced when a value that cannot be represented exactly is approximated to the nearest representable value. It is a major source of error in floating-point arithmetic and repeated calculations.

Operations on binary values using AND, OR, NOT, and XOR. AND yields 1 only when both inputs are 1; XOR yields 1 when inputs differ. They underlie circuit design and bit masking.

A circuit built from gates such as AND, OR, NOT, NAND, and XOR that processes binary signals. Combinations of gates implement adders, comparators, and sequential circuits like flip-flops.

A logic circuit whose output depends not only on current inputs but also on stored past state, typically held in flip-flops and synchronized by a clock signal. Counters and registers are examples.

The processor that fetches, decodes, and executes instructions. It contains the control unit, arithmetic logic unit, registers, and program counter, and its clock frequency and core count affect performance.

A technique that overlaps stages of instruction execution so multiple instructions are in progress at once, improving throughput. Hazards such as data dependencies can stall the pipeline.

A small, fast memory placed between the CPU and main memory that holds frequently used data. Hits are fast; misses require access to slower main memory, so hit rate strongly affects performance.

The primary storage, usually RAM, that holds programs and data currently in use and is directly addressable by the CPU. It is volatile, losing contents when power is removed.

Non-volatile storage such as HDDs and SSDs used to retain programs and data persistently. It is slower than main memory but far larger and cheaper per unit of capacity.

A technique combining multiple disks for redundancy, performance, or both. RAID 0 stripes for speed, RAID 1 mirrors, and RAID 5 stripes with parity, tolerating one disk failure.

System software that manages hardware, schedules processes, allocates memory, and provides file systems and interfaces for applications. Examples include Windows, Linux, and macOS.

A mechanism giving each program an apparent contiguous address space, mapped to physical memory in pages. Pages not in memory are swapped to disk, and thrashing degrades performance.

The policy choosing which page to evict when a page fault occurs and no free frame exists. LRU, FIFO, and optimal algorithms differ in hit rate and implementation cost.

A running program instance with its own address space and resources. Processes are scheduled by the OS, and multiple threads within one process share memory.

A unit of execution within a process that shares the process's memory and files but has its own stack and program counter. Threads enable concurrency with lower overhead than separate processes.

A state where two or more processes each wait for a resource held by another, so none can proceed. It requires mutual exclusion, hold-and-wait, no preemption, and circular wait.

A mechanism ensuring only one process or thread accesses a shared resource at a time, often using locks or semaphores. It prevents inconsistent data but can cause deadlock or waiting.

A database organizing data into tables of rows and columns, with relationships expressed by shared key values and manipulated using SQL. It is grounded in relational algebra.

A column or set of columns that uniquely identifies each row in a table and cannot contain nulls. Foreign keys in other tables reference it to enforce referential integrity.

The process of structuring tables to reduce redundancy and update anomalies by splitting data according to functional dependencies into first, second, and third normal forms.

The standard language for defining, querying, and manipulating relational data. SELECT retrieves rows, JOIN combines tables, and INSERT, UPDATE, and DELETE modify data.

A group of database operations treated as a single logical unit that must satisfy ACID properties: atomicity, consistency, isolation, and durability. It commits entirely or rolls back.

The protocol suite underlying the Internet, combining TCP for reliable, ordered, connection-oriented delivery and IP for addressing and routing packets across networks.

A numeric identifier assigned to a network interface for routing. IPv4 uses 32 bits in dotted decimal; IPv6 uses 128 bits. Subnet masks separate network and host portions.

A bit pattern that identifies which portion of an IP address denotes the network and which denotes the host, enabling subnetting and routing decisions.

The domain name system that translates human-readable host names into IP addresses through a distributed hierarchy of name servers, allowing names to change without affecting users.

An encryption scheme using a key pair: a public key for encryption or signature verification and a private key kept secret. It also enables digital signatures and key exchange.

Encryption where the same secret key is used to encrypt and decrypt. It is fast and suited to bulk data, but the key must be shared securely in advance.

A value computed from a message using the sender's private key that recipients verify with the public key, providing authenticity, integrity, and non-repudiation.

A finite, unambiguous sequence of steps that solves a problem or computes a result. Its efficiency is commonly measured by time and space complexity in big-O notation.

A measure of the resources an algorithm consumes as input size grows, usually expressed in big-O notation. Binary search is O(log n) while linear search is O(n).

A method for locating a value in a data structure. Linear search checks elements one by one, while binary search halves a sorted range each step for much faster lookup.

A method for arranging data in order. Quick sort and merge sort average O(n log n), while bubble and selection sort are O(n^2) and practical only for small inputs.

A last-in, first-out data structure where insertion and removal occur at one end. It is used for function call management, expression evaluation, and depth-first traversal.

A first-in, first-out data structure where elements are added at the rear and removed from the front. It is used for scheduling, buffering, and breadth-first traversal.

A technique where a function calls itself on a smaller subproblem, requiring a base case to terminate. Each call consumes stack space, so deep recursion risks overflow.

A diagram representing an algorithm with standardized symbols: ovals for start and end, parallelograms for input and output, rectangles for processing, and diamonds for decisions.

A structured, programming-language-like notation used in exam questions to describe algorithms without the syntax details of any real language, emphasizing logic and control flow.