Notes, summaries, assignments, exams, and problems for Computers

The Counting Principles

Counting is the action of finding the number of elements in a finite set of objects. Here are the key principles:

1. The Stable-Order Principle: To count effectively, the list of words used (like one, two, three) must be in a repeatable order.
2. The One-to-One Principle: This involves assigning one, and only one, distinct counting word to each item being counted.
3. The Cardinal Principle: When the one-to-one and stable-order principles are followed, the number name given to the final object in a collection represents the total number of items in that collection.
4. The Order-Irrelevance Principle: This principle highlights that the order in which items are counted doesn't affect the total count.
5. The Abstraction Principle: These counting

Introduction

This program demonstrates how to draw a 3D cube in OpenGL and perform various transformations on it, including scaling, translation, and rotation about one axis.

Code

#include <GL/glut.h>

bool movingRight = false;
float xLocation = 0.0f;

void display() {
  glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
  glClear(GL_COLOR_BUFFER_BIT);
  glLoadIdentity();
  glTranslatef(0.0f, 0.0f, -5.0f);
  glTranslatef(xLocation, 0.0f, 0.0f);
  glutWireCube(2.0f);
  glutSwapBuffers();

  if (movingRight)
    xLocation -= 0.05f;
  else
    xLocation += 0.05f;

  if (xLocation < -3.0f)
    movingRight = false;
  else if (xLocation > 3.0f)
    movingRight = true;
}

void reshape(int width, int height) {
  glViewport(0, 0, (GLsizei)width, (GLsizei)

PL/SQL Components for Race Management

The following PL/SQL objects demonstrate core database programming concepts, including custom functions for calculation, procedures for data manipulation and ranking, and triggers for auditing.

1. Calculating Global Time: The tempo_global Function

This function calculates the total elapsed time for a specific pilot by summing the duration of all stages recorded in the TempoEtapas table. It includes robust error handling using SQLCODE.

CREATE FUNCTION tempo_global (ID_piloto IN NUMBER)
RETURN NUMBER
IS
    soma_tempo NUMBER;
    coderro NUMBER;
    CURSOR c1 IS
        SELECT tempo_inicio, tempo_fim
        FROM TempoEtapas
        WHERE Piloto_idPiloto = ID_piloto;

BEGIN
    soma_tempo := 0;
    FOR item IN

1.  A network technician is configuring port Security on a LAN switch interface. The security policy requires host MAC Addresses to be learned dynamically, stored in the address table, and Saved to the switch running configuration. Which command does the technician Need to add to the following configuration to implement this Policy? Switch(config)# interface fa0/1 
   Switch(config-if)# switchport mode access 
   Switch(config-if)# switchport port-security

·Switch(config-if)# switchport port-security mac-address sticky

2. On which switch interface would an Administrator configure an IP address so that the switch can be managed Remotely?

·VLAN 1

3. Refer to the exhibit. Match the packets with Their destination IP address to the exiting interface on the router.

Understanding IGRP Protocol

What is IGRP?

IGRP is a Cisco-specific protocol developed in the mid-1980s.

IGRP Advantages Over RIP

IGRP calculates a composite metric from a set of route variables. It can be implemented on networks of up to 255 hops in diameter. Additional advantages include:

• Unequal-cost load sharing
• An update period three times longer than RIP's
• A more efficient update packet format

Unlike RIP, which uses UDP, the IGRP process is accessed directly from the IP layer as protocol 9.

IGRP Routing and Process Domains

Using domains allows isolating communications within one domain from others. IGRP uses two types: routing domains and process domains.

• Routing domains: Defined by Autonomous System (AS) boundaries and communicate via Exterior Gateway

OPENFLOW:

defines OpenFlow as the first standard communications interface defined between the control and forwarding layers of an SDN architecture. OpenFlow allows direct access to and manipulation of the forwarding plane of network devices such as switches and routers, both physical and virtual 

OPENFLOW CONFIG CONCEPTS

OF Capable Switch: Physical OF switch.  Can contain one or more OF logicalswitches.

OpenFlow Configuration Point: configurationservice

OF Controller: Controls logical switch via OFprotocol

Operational Context: OF logicalswitch

OF Queue: Queues of packets waiting forforwarding

OF Port: forwarding interface. May be physical orlogical.

OF Resource: ports, queues, certificates, flow tables and other  resources of OF capableswitches 

Discuss the advantages of address aggregation (summarization) with respect to routing table size, routing update exchange, and routing optimization?

Route aggregation and subnetting shrink the size of routing tables used by routers. Without CIDR, a router must maintain many individual entries for routes within the same network. CIDR guarantees more efficient routing and reduces the number of CPU cycles when updating a routing table. It also reduces router memory requirements.

What are the key characteristics or requirements that should be fulfilled by any routing protocol?

A routing protocol should guarantee loop-free paths, calculate multi-hop optimal paths, use simple or composite network metrics, be scalable, converge rapidly, use network resources... Continue reading "Advantages of Address Aggregation and Key Characteristics of Routing Protocols" »

Managing operating systems on workstations boils down to three basic tasks: loading the system
software and applications initially, updating the system software and applications, and
configuring network parameters.
We call these tasks the Big Three.

The Five States

The diagram depicts five states: new, clean, configured,
unknown, and off.

• New refers to a completely new machine.
• Clean refers to a machine on which the OS has been installed
  but no localizations performed.
• Configured means a correctly configured and operational
  environment.
• Unknown is a computer that has been misconfigured or has
  become out of date.
• Off refers to a machine that has been retired and powered off.

Transitioning Between States

There are many ways to get from one lifestyle... Continue reading "Managing Operating Systems on Workstations: The Big Three" »

Listas Ligadas em C++: Adicionar, Excluir, Buscar e Imprimir

Implementação básica de uma lista simplesmente ligada em C++, cobrindo as operações essenciais de manipulação de dados.

Configuração Inicial em C++

#include <iostream>
using namespace std;

Classe Node (Nó)

Define a estrutura fundamental de cada elemento da lista.

class Node {
    public:
        int value; // Pode ser implementado qualquer tipo de dados aqui.
        Node *next;
        
        Node () {
            next = NULL; // Construtor Padrão
        }
        
        Node (int _value) { // Construtor com Atribuição de Valor
            value = _value;
            next = NULL;
        }
};

Classe List (Lista Ligada)

Gerencia a coleção de nós e as operações... Continue reading "Implementação de Listas Ligadas em C++ (CRUD)" »

Computer System Essentials

Core Operating System Components

Kernel: The OS's Foundation

The operating system's core, a platform that allows other software to execute.

Shell: User Interaction Interface

The operating system's interface for users to interact with all computer elements.

Thread: A Running Program or Task

Any program or task that is currently running.

File System: Data Storage & Retrieval Protocol

A protocol that defines how files are stored and retrieved on disk drives, or by threads and programs.

Disk Formatting: Setting a File System

The process of setting a disk's file system.

Major Operating Systems and Their Focus

• Microsoft Windows: Focuses its operating system on security.
• Linux: Emphasizes customizability.
• Chrome OS: Centered on web