Notes, summaries, assignments, exams, and exercises for Computer science for Vocational training

Magnetic Storage Peripherals

Magnetic storage uses a ferromagnetic layer material (disks or hard drives).

Floppy Disk Drives

Floppy disks read and record information. Key parts include:

• Engine torque mechanism
• Shaft reading heads
• Ejecting mechanism and floppy connector

Hard Disk Drives (HDDs)

HDDs use tough aluminum platters that spin at high speed. The drive writes or reads data tracks.

Methods for Storing Information

• CHS (Cylinder, Head, Sector): Information is located by knowing the face, track, and sector.
• LBA (Logical Block Addressing): Data is accessed by calling a logical block number and searching for it.

HDD Physical Structure

The physical structure consists of:

• Platters (disks)
• Heads
• Spindle motor (engine torque)
• Head displacement mechanism (DLS heads)

Obtener elementos del DOM

const resultsContainer = document.getElementById('results');
const favoritesContainer = document.getElementById('favorites');
const readContainer = document.getElementById('read');

Buscar libros en OpenLibrary usando fetch().then()

function fetchBooks(query, limit = 10, callback) {
  fetch(`https://openlibrary.org/search.json?q=${encodeURIComponent(query)}&limit=${limit}`)
    .then(res => res.json())
    .then(data => {
      const books = data.docs || [];
      callback(books);
    })
    .catch(err => {
      console.error("Error fetching books:", err);
    });
}

Guardar en localStorage si no está duplicado

function saveToLocalStorage(key, book) {
  const stored

Internet Technologies

The internet relies on several key technologies:

• Transmission Control Protocol (TCP): Enables connections and data exchange between hosts.
• Internet Protocol (IP): A unique 32-bit numeric address for each computer, represented by four numbers (0-255) separated by periods.
• Domain Name System (DNS): Converts domain names (e.g., google.com) to IP addresses.
• Hypertext Transfer Protocol (HTTP): The standard for transferring web pages.
• Hypertext Markup Language (HTML): Formats documents and links to other resources.
• Uniform Resource Locator (URL): References a web resource's location and retrieval method.

Cloud Computing

Cloud computing provides access to shared computing resources over a network. Different service models exist:

• Software

1. Telephone communication

it has been the medium used as the first contact with a company. It is used to arrange meetings , interviews or to ask for information, so the impression of the first telephone call is very important

2. Telephone means and equipment

Fixed individual devices

Private branch exchanges (PBX):  it connects calls between two destinations or ends

Mobile devices:

PDA (Personal Digital Assistant) it`s like a small computer (Internet and electronic mail)

Smartphone:  A PDA with video, camera, radio, MP3 player  or television

Services: Internet, e-mail, videoconference, camera, audio and  Video quality player, an agenda, GPS,....

3. Additional services offered by the telephone equipment

3.1 Common features(a,b,c,)

1. Fixed telephony: -

Notice

Implementación de la Clase Conecta

A continuación, se presenta la estructura de la clase Conecta, diseñada para gestionar la conexión a una base de datos Oracle mediante JDBC.

Código Fuente

package cl.duoc.tap.solemne3.datos;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class Conecta {
    private String ip;
    private String puerto;
    private String usuario;
    private String password;
    private String baseDatos;
    private String driver;
    private Connection conn;

    public Conecta(String ip, String puerto, String usuario, String password, String baseDatos, String driver) {
        this.ip = ip;
        this.puerto = puerto;
        this.usuario = usuario;
        this.password

Chapter 7: Wireless LAN Fundamentals

802.11 Architecture and Operations

1. What are the main planes in a WLAN architecture?

• A) Management
• B) Control
• C) Data

2. Which plane handles signaling and coordination?

• A) Control

3. Which plane handles configuration and monitoring?

• B) Management

4. Which mechanisms are used for channel access in 802.11?

• A) CCA (Clear Channel Assessment)
• D) VCS (Virtual Carrier Sense)

5. What is the shortest interframe space in 802.11?

• C) SIFS (Short Interframe Space)

6. How many address fields are typically in an 802.11 frame?

• D) 4

7. What type of frame is sent by an AP in response to a client's probe request?

• A) Probe Response

8. What is used to derive the encryption keys in WEP?

• D) The WEP passphrase

9. What type of scanning involves listening

Software: Definition and Functions

Software is the intangible component of any computer system. It consists of a collection of rules and guidelines that establish the relationship between the user and the machine.

Functions of Software

1. To reduce manual entry of information.
2. Provide communication media between man and machine.
3. Encourage greater use of media and reduce the processing time of files.
4. Provide routines that automatically perform repetitive, classified work.

Software Classification

System Software

A series of programs that facilitate man-machine communication, permitting its proper exploitation.

Application Software

Programs developed to solve specific problems. These can be classified into:

Basic or Utility Programs

These are applications whose...

Disk Quota Management in Windows Server 2008

Windows Server 2008 offers two distinct types of disk quotas to help manage storage utilization:

• NTFS Disk Quotas

  Available in all versions of Windows Server 2008, NTFS Disk Quotas allow administrators to manage the disk space used by users. Quotas are set for each volume. While users receive warning messages when exceeding their quota, event logging is the primary communication channel for disk quota management.

• File Server Resource Manager (FSRM)

  Windows Server 2008 supports File Server Resource Manager (FSRM) for advanced quota management. FSRM enables the management of space utilization for specific folders and volumes. Users approaching or exceeding their limits will automatically receive email notifications.

This document presents a Java class named Student, demonstrating object-oriented programming principles. It includes attributes, constructors, getters, setters, and methods to calculate average grades and determine student status.

Test Class

import java.io.*;
public class Test {
    public static void main(String[] args) throws IOException {
        Student student = new Student("John", true, 3, 2, 5, 43);
        student.show();
    }
}

Student Class

import java.io.*;
public class Student {
    private int note1, note2, note3;
    private String name;
    private int age;
    private boolean sex; // attributes

    public Student() {
        this.name = "NN";
        this.sex = false;
        this.note1 = 0;
        this.note2 = 0;
        this.

What is a DNS Service?

A DNS service is a distributed database that stores hierarchical information associated with domain names on a network.

Primary Uses of DNS

• Name Resolution: Given the full name of a host, the service retrieves its IP address.
• Reverse Address Resolution: This is the inverse of the previous mechanism. Given an IP address, it retrieves the name associated with it.
• Mail Server Resolution: Given a domain name, it identifies the server through which email delivery should be handled.

Core Components of the DNS Service

The main components include:

• The DNS Client: A program that runs on the user's computer and generates DNS resolution requests for names to be sent to a DNS server.
• DNS Servers: These answer customer requests. Recursive