a2 Comp Sci definitions

CISC (Complex Instruction Set Computer)

An architecture for CPUs that features a large and complex instruction set, allowing for multi-clock-cycle instructions. It emphasizes hardware efficiency and enables variable-length instruction formatting, which can lead to improved performance in specific applications by reducing the number of instructions needed to perform tasks.

RISC (Reduced Instruction Set Computer)

An architecture for CPUs that focuses on a simplified and smaller instruction set, allowing most instructions to be executed in a single clock cycle. RISC designs utilize hardwired logic and a greater number of general-purpose registers to enhance efficiency and speed in executing operations.

Pipelining

A technique used in CPU design to enhance performance by allowing multiple stages of instruction execution—such as Fetch, Decode, and Execute—to be overlapped. This leads to a higher throughput of instructions processed simultaneously, improving overall efficiency.

Interrupt

A critical signal generated by hardware devices or software applications that requires immediate attention from the CPU. When an interrupt occurs, the current task is paused, allowing the processor to respond to the request, facilitating real-time processing and task management.

User-Defined Data Type

A programming construct that allows developers to create custom data types based on built-in data types. These user-defined types are tailored to meet specific needs within a program, improving clarity, organization, and structure.

Non-Composite Data Type

An essential data type representing a single scalar value that cannot be subdivided into smaller parts. Examples include INTEGER, REAL, BOOLEAN, CHAR, and ENUMERATED types, which form the basic building blocks of programming.

Composite Data Type

A data structure that combines multiple other data types, facilitating the storage of related values. This category includes types like SET, RECORD, and CLASS, enabling more complex data representations.

Enumerated Data Type

A user-defined data type consisting of a distinct set of named values arranged in a specified order. Enumerated data types provide meaningful identifiers for representing states or options within a program, enhancing readability and usability.

Record

A composite data structure with a fixed number of fields, each capable of holding different data types. Records organize related data items under a single identifier, facilitating structured data manipulation.

Random-Access File (Direct-Access File)

A file organization method that permits direct storage and retrieval of records at specific memory or disk locations. This approach negates the need for sequential searching and is commonly implemented using a hashing algorithm linked to a primary key for efficient access.

Hashing Algorithm

A computational function that transforms a record key into a specific physical address or location in memory or on disk to store or retrieve the record efficiently. Hashing enables quick access to data by computing a unique address from the key.

Collision

An event that occurs when two different primary keys produce the same hash address in a hashing algorithm. This necessitates the implementation of strategies to handle conflicts and ensure correct data retrieval.

Protocol

A set of standardized rules and conventions that govern how data is structured, transmitted, and controlled across networks. Protocols ensure effective communication and interoperability between different systems and devices.

TCP/IP Suite

A comprehensive ensemble of networking protocols structured within a four-layer architecture, designed to enable reliable end-to-end communication across various computer networks. It establishes standards for data transmission over the internet.

TCP (Transmission Control Protocol)

A reliable, connection-oriented protocol that manages data packet transmission to ensure they are sent in order, acknowledges receipt, and retransmits any lost packets. TCP is essential for applications requiring guaranteed delivery of information.

UDP (User Datagram Protocol)

A connectionless protocol that operates with low overhead and does not guarantee delivery or acknowledgment of packets. UDP is commonly used for time-sensitive applications such as video streaming and online gaming, where speed is prioritized over reliability.

Overflow Area (Chaining)

A strategy for handling collisions in hashing algorithms by storing records that cannot be accommodated in their original location in a designated overflow area. This method uses pointers to link the primary storage location to the overflow area for seamless retrieval.

TCP/IP Stack Layers

The four distinct hierarchical layers in the TCP/IP model: the Application Layer (for user interaction and data presentation), the Transport Layer (for ensuring reliable data transport), the Internet Layer (for data routing), and the Link Layer (for physical data transmission).

Application Layer

The highest layer in the TCP/IP model that interacts directly with users via software applications. It is responsible for data formatting and presenting information, supporting protocols like HTTP, FTP, SMTP, and DNS.

Transport Layer

The layer dedicated to establishing end-to-end connections for reliable data transfer, ensuring correct sequencing of packets, error detection, and the reassembly of data packets. Key protocols in this layer include TCP and UDP.

Internet Layer

This layer handles logical addressing (IP addresses) and routing of data packets across interconnected networks, ensuring that information reaches its intended destination effectively.