Computer Science Articles - Page 61 of 62

Cache is a type of memory that is used to increase the speed of data access. Normally, the data required for any process resides in the main memory. However, it is transferred to the cache memory temporarily if it is used frequently enough.A diagram to better understand the data transfer in cache management is as follows −Cache PerformanceThe cache performance can be explained using the following steps −If a process needs some data, it first searches in the cache memory. If the data is available in the cache, this is termed as a cache hit and the data is accessed ... Read More

A distributed system contains multiple nodes that are physically separate but linked together using the network. All the nodes in this system communicate with each other and handle processes in tandem. Each of these nodes contains a small part of the distributed operating system software.A diagram to better explain the distributed system is −Types of Distributed SystemsThe nodes in the distributed systems can be arranged in the form of client/server systems or peer to peer systems. Details about these are as follows −Client/Server SystemsIn client server systems, the client requests a resource and the server provides that resource. A server ... Read More

Computer storage has components that store computer data. The different storage types in the storage hierarchy are as follows: Primary Storage This is also known as the main memory and is the memory directly accessible by the CPU. All the instructions are executed in the main memory by CPU and the data required by these instructions is also stored in main memory. Main memory primarily consists of the RAM which is volatile in nature. It is also quite small compared to secondary memory and expensive as well. Secondary Storage Secondary or external storage is not directly accessible by the ... Read More

Computer storage contains many components that are used to store computer data. Some information about the various storage devices is given below.Computer Storage DefinitionsThe computer storage devices include Primary and Secondary Storage devices. These are explained in detail as follows −Primary Storage DevicesPrimary storage is also known as the main memory and is the memory directly accessible by the CPU. Some primary storage devices are −ROMROM is read only memory. This memory cannot be changed, it can only be read as required. Since ROM is unchangeable memory, it is used by data and programs that are frequently required and seldom ... Read More

The computer system is a combination of many parts such as peripheral devices, secondary memory, CPU, etc. This can be explained more clearly using a diagram.The salient points about the above figure displaying Computer System Organisation is −The I/O devices and the CPU both execute concurrently. Some of the processes are scheduled for the CPU and at the same time, some are undergoing input/output operations.There are multiple device controllers, each in charge of a particular device such as keyboard, mouse, printer etc.There is buffer available for each of the devices. The input and output data can be stored in these ... Read More

A hierarchical model represents the data in a tree-like structure in which there is a single parent for each record. To maintain order there is a sort field which keeps sibling nodes into a recorded manner. These types of models are designed basically for the early mainframe database management systems, like the Information Management System (IMS) by IBM.This model structure allows the one-to-one and a one-to-many relationship between two/ various types of data. This structure is very helpful in describing many relationships in the real world; table of contents, any nested and sorted information.The hierarchical structure is used as the ... Read More

In a "class roster" database, a teacher may teach zero or more classes, while a class is taught by one (and only one) teacher. In a "company" database, a manager manages zero or more employees, while an employee is managed by one (and only one) manager. In a "product sales" database, a customer may place many orders; while an order is placed by one particular customer. This kind of relationship is known as one-to-many.The one-to-many relationship cannot be represented in a single table. For example, in a "class roster" database, we may begin with a table called Teachers, which stores ... Read More

Relational database design (RDD) models’ information and data into a set of tables with rows and columns. Each row of a relation/table represents a record, and each column represents an attribute of data. The Structured Query Language (SQL) is used to manipulate relational databases. The design of a relational database is composed of four stages, where the data are modeled into a set of related tables. The stages are −Define relations/attributesDefine primary keysDefine relationshipsNormalizationRelational databases differ from other databases in their approach to organizing data and performing transactions. In an RDD, the data are organized into tables and all types ... Read More

A database model determines the logical structure of a database and determines in which manner data can be stored, organized and manipulated on a fundamental basis. before the databases are designed, the only way to store data was are in file storage, which increases the complexity as programmers had to go to great lengths to extract the data, and their programs had to perform complex parsing and relating.There are various languages like Perl process the text in an easier manner due to its powerful regular expressions. However, accessing the data from files is still a complex task. There is no ... Read More

The graph is a collection of nodes and edges where each node is used to represent an entity and each edge describes the relationship between entities. A graph-oriented database, or graph database, is a type of NoSQL database that uses graph theory to store, map and query relationships.Graph databases are basically used for analyzing interconnections. For example, companies might use a graph database to mine data about customers from social media.