Mapa conceptual | Unidad 1 | INGLES

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Unit 1: Introduction to Operating Systems and Their Installation

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Structure of a Computer System

Architecture of an Operating System

Functions or Services of an Operating System

Types of Operating Systems

Software applications

Operating system virtualization

Operating System Installation: Requirements, versions, and licenses

Start-up managers

Licenses and types of licenses

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2.1 Components of an Operating System

Kernel

Utility Programs

Utilities for Memory Management

They are responsible for allowing the user to communicate with the system through graphical or text environments using a command line interface.

Utilities for Process Management

It controls the running processes in tasks such as starting, stopping, coordinating, creating and destroying processes, switching, detecting, and starting messages.

User Interface Program or Shell

It is responsible for managing memory for processes and programs, allocating available memory among different processes.

Functionalities

Communication

Between software programs and hardware. It is responsible for providing secure access to the computer's hardware for different programs or, more basically, for managing access.

Task Management

Since there are many programs and access to hardware is limited, the kernel is also responsible for deciding which program can use a hardware device and for how long.

Hardware Management

It is responsible for managing resources through system call services.

The Kernels

Kernels ensure the loading and execution of processes through a module called the loader, which is responsible for loading programs into memory. It is loaded when the system starts and remains in memory until the system is shut down.

Monolithic Kernels

They are responsible for managing IRQs, memory, I/O devices, system calls, file management, and process scheduling. Monolithic kernels are usually easier to design correctly.

Microkernels

They are responsible for managing processes and threads, memory management, communications, and low-level I/O operations. Other services, such as file management, use the kernel through communications.

Hybrid Kernels

Or modified microkernels, as they include additional code in the kernel space to execute more quickly.

Exokernels

They allow the use of libraries that provide greater functionality due to direct or nearly direct access to the hardware.

It is responsible for managing the processor. It has other functionalities such as communication between software programs and hardware, task management, and hardware management.

Se encarga de gestionar el Procesador. Tiene otras funcionalidades como la comunicación entre programas informáticos y el hardware, la gestión de las distintas tareas, la gestión del hardware.

2.1.2 Command Interpreter. Utility Programs of an Operating System

It is a software program that acts as a user interface to communicate with the operating system through a graphical screen or window, waiting for commands typed by the user on the keyboard, interpreting them, and passing them to the operating system for execution.

Functions Controlled by the Operating System

Process Management

They are executed through tasks such as creating, deleting, stopping, resuming, communicating, and synchronizing the use of the CPU, memory, and machine devices.

I/O System Management

Of data and files, performing tasks such as maintaining data in secondary or external storage with scheduling of different disk volumes, and managing temporary storage memory or cache memory.

Address Control

Of the main memory where processes and data in execution are stored, controlling the spaces of free and used memory, location tables of specific information, etc.

File System Management

Allowing the related organization of data and file storage through the allocation of units and directories.

Other Utilities

Such as: the audit system for program protection, a network-based communication system to interconnect systems through network interfaces, support for creating custom processes by providing programming languages (compilers, interpreters, etc.), and processes for information about the system's status, etc.

3.1 Controling Processes

Un proceso es un programa o tarea en ejecución al cual el sistema operativo asignará recursos y controlará su ejecución. Se denomina hilo o hebra a un punto de ejecución de un proceso.

La información que nos aporta el sistema en la estructura de bloque de datos generada para cada proceso es:

Process State

It can present the following states:

Process Identification Code or PID

Priority Value When Assigning System Resources

Allocated Memory Area

The hardware status, information for managing memory, and the status of the I/O system.

Execution or Active

Cuando el proceso recibe alguna señal para continuar ejecutándose. En el caso de sistemas con un único procesador, sólo puede haber un proceso en dicho estado en un instante dado.

Ready or Prepared

Se encuentran todas las tareas que están listas para ejecutarse pero que esperan a que el procesador quede libre ya que hay otros procesos más prioritarios en ejecución.

Blocked or Suspended

Sucede cuando el proceso ha agotado su tiempo de ejecución y debe dejar paso al siguiente proceso.

Dead

Un proceso está en este estado cuando ha terminado su ejecución de manera correcto o porque se ha producido un error en su ejecución

Zombie or Ignored

El proceso existe pero todavía no es conocido por el sistema operativo.

3.1.1 Process Scheduler

3.1.2 Process Scheduling Representation. Process Blocking Control

3.2 Control and Manage Memory

3.2.1 Memory Management Techniques

3.3 Control Peripheral Devices. Classification of Peripherals

3.4 Control File Organization

7. Boot loaders

7.1. Concepts related to operating system booting

7.2. Windows Boot Managers

7.3. Linux Boot Managers

8.1. Requirements, Distributions, and Considerations for Installing Windows 7

8. Installation of Operating Systems: Requirements, Versions, and Licenses

8.1.2. Features of the Installed Windows 7 System

8.2. Requirements, Distributions, and Considerations for Installing Windows Server

8.3. Requirements, Distributions, and Considerations for Installing Linux

8.3.2. Characteristics of the Installed Linux System

La planificación de los procesos se suele representar gráficamente utilizando los diagramas de Gantt o diagramas temporales de la posesión del procesador. En los sistemas de tiempo compartido, multiprocesos, multitarea o multihilo se pueden presentar problemas a la hora de competir por los recursos del sistema esto se soluciona mediante el llamado control de bloqueos de los procesos.

El bloqueo de procesos se debe de producir cuando dos o más programas necesitan utilizar algún recurso del sistema de software o hardware a la vez.

Alguna de las técnicas para evitar bloqueos son:

Asignación todo-nada

El proceso pide todos los recursos que va a utilizar de una vez y el sistema se los asigna si puede dárselos todos.

Algoritmo del banquero

Utiliza una tabla de recursos. Cuando un proceso pide un recurso mira en la tabla si está disponible si no hace esperar al proceso.

Asignación de recursos en orden lineal

Los recurso tienen asignado un valor y los procesos sólo hacen uso de recursos con valores mayores que al que se le asigna al proceso.

3.1.2. Representación de la planificación de procesos. El control de bloqueo de procesos

5. Informatic application

According to their functions, programs can be classified.

System software

Responsible for providing the user with control of the computer system in an unattended manner, using interactive tools for proper maintenance.

Application software

Designed to facilitate the user in performing a specific type of task.

5.1. Client-server application model: distributed applications

The components that appear in these distributed application work environments are:

The client computer initiates the communication.

With the server via an access protocol to request data or for it to perform specific tasks.

The server computer has the tools to process requests.

Even from several clients at the same time and send the appropriate response.

The middleware will be the interface that provides connectivity between applications.

Through a software layer that protects software developers from having to handle low-level details of different communication protocols, operating systems, and other architectures such as databases.

We can find different classifications in the client-server model.

In terms of process load between the client and the server:

Heavy client-light server

The core of the application runs on the client

Hevay server-light client

Most of the application runs on the server side.

By the assigned functions of the features

Two-tier

They are applications that allow computers called workstations to request services from other computers called servers, which contain the data, allowing the client to present the results of the process performed on the client computer, the server, or even both.

Three-tier

It allows connecting multiple applications to create a larger application, offering a set of services that enables the functioning of applications across heterogeneous platforms.

Multilevel

Processing can be divided into a multi-layer system, allowing complex application tasks to be divided into simpler tasks across multiple servers.

By the service offered by the servers

Database servers

Servers that manage requests made by clients using the query language (SQL).

Transaction servers

The client process calls functions that reside on the server so that the exchange over the network occurs in a single request-response access, independent of the application.

Web servers

Requests made using the HTTP communication protocol.

File servers

Allows remote access to files stored on a server computer. The protocols typically used are SMB and NFS.

Los periféricos de entrada/salida son dispositivos hardware que junto con los soportes se encargan almacenar, leer datos y programas que serán procesados por el sistema.

3.3. Controlar los dispositivos periféricos. Clasificación de periféricos

Para facilitar la comunicación entre el usuario y los dispositivos, el sistema operativo aporta los denominados interfaces de comunicación que pueden ser:

Interfaz tipo texto .

Todas las órdenes que el usuario introduzca y las respuestas que el sistema operativo dé se visualizarán mediante cadenas de caracteres.

Interfaz tipo gráfico .

La información en pantalla se muestra en ventanas, y en ellas aparecen una serie de componentes y objetos que sirven para enviar o recibir información sin tener que teclear nada.

Los periféricos se pueden clasificar según su función de su uso:

De entrada

Son los que sirven para introducir información (datos o programas) en el ordenador.

De salida

Son los que se utilizan para extraer la información (datos en forma de resultados, programas, etc.) desde la memoria y el resto de componentes internos del ordenador y mostrar los datos.

De entrada/salida (E/S)

Son los que se utilizan para introducir o extraer datos desde y hacia el ordenador.

After turning on the computer, the first thing the CPU does is execute the machine code stored at a predefined memory address. This code represents the BIOS; one of its functions is to search for a special program that executes the so-called bootloader (LILO or GRUB). The MBR is the sector of the hard drive that contains the bootloader, which will search for the Kernel (core of the Linux System) to place it in memory and provide the CPU with the address to execute it. Additionally, the MBR contains the partition table. Currently, GRUB is used more than LILO because it is more powerful than LILO.

The GRUB is the tool responsible for starting the different operating systems installed on the computer. The most important features are: - It allows modifying its configuration without needing to reinstall GRUB - It is compatible with file systems ext2, ext3, ReiserFS, Fat32, and NTFS - The menu can be customized with images or by changing the background.

7.3.1. The GRUB Bootloader for Linux

To configure GRUB, we must modify the file /boot/grub/menu.lst; some of the options are:

If we want to add a new OS option to the menu, we should add the following command lines:

If we want to add a new OS option to the menu, we should put the following command lines.

Among the most used distributions of Linux, we can find:

Red Hat Enterprise Linux

Also known by its acronym RHEL, it is a commercial Linux distribution developed by Red Hat. Its software is packaged in RPM format.

Ubuntu

It provides an updated and stable operating system for the average user, with a strong focus on ease of use and system installation. Like other distributions, it is composed of multiple software packages typically distributed under a free or open-source license.

Mandriva

It is a Linux distribution published by the French company Mandriva, aimed at both beginners and experienced users.

Debian

It is a community made up of developers and users that maintains a GNU operating system based on precompiled free software packaged in a simple format for multiple computer architectures and various kernels. It is not commercial as it does not depend on any company for its development.

6. Licenses and types of licenses

According to the criteria outlined in the usage contract (it is advisable to read the terms before accepting them), we can find different classification modes, one of which could be used by many internet portals that distribute software, which usually identify it with one of these types based on its usage and design:

FreeSoftware

It can be used, copied, distributed, and modified (when the source code is available) to improve the program or adapt it to needs.

Owner or private Software

It is one that prohibits copying, redistribution, or modification without the owner's permission. Permission is usually required from the organization that developed it to use it.

Commercial Software

To access it, a payment must be made. There can be both free and proprietary software of this type.

Public Domain Software

Public domain software is software without copyright. It allows for use, copying, modification, or redistribution with or without profit.

Freeware

Programs that allow redistribution but not modification, and that sometimes include their source code. These programs are not completely free software.

Shareware

It is software available with permission to be redistributed, but its use is limited in time or functionality (it does not include all processes). To have full availability, a payment must be made.

GPL

It can be considered as a free software license with inherited protection. Its purpose is to declare that the software covered by this license is free software and to protect it from attempts at appropriation that would restrict those freedoms for users, preventing this software from being integrated into proprietary software.

Whit Copyleft

That software has a type of copyright created for free software, which does not allow adding usage rules beyond those specified in the license determined by the original author. The license details the conditions under which it guarantees the freedoms of use.

DFSG

It is part of the contract between Debian and the free software user community.

BSD

This type of license allows the creation of a derivative work without any obligation to maintain protection. It can be argued that this license ensures "true" free software, in the sense that the user has unlimited freedom with the software, including the freedom to redistribute it as non-free (i.e., for sale) without the obligation to include the source code.

MPL-style licenses

Es Software Libre y promueve eficazmente la colaboración evitando el efecto "viral" de la GPL.

7.1. Concepts Related to Operating System Booting

The BIOS

The BOOTLOADER

The BOOTSTRAP

It is a piece of software code that locates and recognizes all the devices needed to load the operating system into RAM. Its primary function is to find the operating system and load it into RAM.

It is a simple program that does not have all the functionalities of an operating system, designed exclusively to prepare everything the operating system needs to function.

Describes the booting or startup process of any computer. It usually refers to the program that boots an operating system, such as GRUB, Lilo, or NTLDR. It runs after the POST process of the BIOS.

When multiple processes are ready to execute, the operating system must decide which one should use the processor. The module responsible for this task is called the scheduler.

Functions and Objectives of the Scheduler:

Fairness

By allocating processor usage time as fairly as possible.

Efficiency

To service the maximum number of processes possible to ensure that the processor is occupied for the longest time possible.

Low Response Time

To ensure good response times for users by providing sufficient resources when needed.

High Performance

By maximizing the number of processes that execute in a period of time, activating the processes that are in the ready state.

Scheduling Algorithms

FIFO (First In Fist Out)

Processes are executed in the order they arrive (first come, first served).

Round-Robin Algorithm

It sequentially assigns the same execution time (quantum) to different processes in a round-robin manner.

Priority Scheduling Algorithm

It assigns execution times based on a priority list.

SJF Algorithm

The shortest job is executed first.

Measures or Values to Evaluate Scheduling Algorithms

CPU Burst Time

It is expressed as a percentage of the average utilization time, that is, the percentage of time the processor is busy.

Productivity (P)

The number of processes or jobs executed per unit of time.

Turnaround Time (TT)

It is the sum of the actual or useful execution time and the time spent waiting for resources. TF=E+U (tiempo CPU).

Waiting Time (W)

It is the time the process waits until it is granted the processor, that is, the time it has been in the ready state.

Service Time

Time taken for a process to execute from loading, waiting, execution, and during input/output accesses.

3.1.1 Process Scheduler

It is an operating system from Microsoft based on an improved NT kernel 6.0 (multitasking and can work with both single-processor computers and symmetric multiprocessing computers), and it has a more user-friendly interface.

In order of the number of functions they perform, we can find the following available distributions of Windows 7:

Windows 7 Starter

Facilitates the use of portable devices.

Windows 7 Home Premium

Allows you to create a home network and share your photos, videos, and music more easily.

Windows 7 Professional

You can run several productivity programs from Windows XP in Windows XP Mode and easily recover data with automatic backups on the network.

Windows 7 Enterprise/Ultimate

It has the capability to run several productivity programs from Windows XP in Windows XP Mode. To achieve greater security, it can encrypt data with BitLocker and BitLocker To Go.

Other versions of Windows are:

Windows 10

It introduced the virtual assistant Cortana and improvements in security and user interface.

Windows 8

The version that changed the design of Windows with a start screen featuring interactive icons. It also included the Windows app store and the ability to use touch devices.

Windows 11

The most recent and advanced version of Windows, featuring a more minimalist design and integrated AI advancements (Copilot).

Windows vista

The version that introduced the Aero effect, which gave a more modern and transparent look to Windows. It also improved security, parental controls, and file searching.

3.2. Controlar y gestionar la memoria

El administrador o gestor de memoria es el módulo del sistema operativo encargado controlar el espacio en memoria para poder alojar los procesos, también de liberarla cuando hayan finalizado, controla el intercambio de datos entre los dispositivos y de la protección de los datos almacenados.

Podemos realizar la siguiente clasificación de los tipos de memoria:

Según su función

Según su posibilidad de acceso

Memoria interna

Memoria principal o central

Se encarga de almacenar los programas y los datos que ejecutará el ordenador. Dispone de una gran velocidad de acceso, pero con poca capacidad de almacenamiento.

Memoria caché

Proporciona una gran velocidad de acceso para acelerar el rendimiento del sistema.

Memoria de registros

Pequeñas direcciones de memoria temporales que guardan los datos en el momento en el que son objeto de procesamiento.

Memoria externa o secundaria

Es aquella que se emplea como almacenamiento pasivo en un dispositivo periférico como un disco duro, CD, etc.

RAM

Memoria de acceso aleatorio. Es volátil cuando se interrumpe la alimentación, la RAM pierde su contenido. Según su funcionamiento se distinguen dos tipos:

ROM

Memoria de sólo lectura ya que podemos leer su contenido pero no escribirlo. La información que contiene la ROM se escribe en el momento de su fabricación y, a partir de entonces, ya no puede cambiarse.

SRAM o RAM Estática

No pierde su contenido mientras recibe alimentación eléctrica. Esta memoria es muy rápida pero su fabricación es más costosa que las otras.

DRAM o RAM Dinámica

Pierde el contenido con el tiempo aunque no se interrumpa el suministro de energía. Para evitar pérdidas de datos es necesario reescribir su contenido continuamente: es lo que se llama refresco de la memoria.

Some of the basic features or utilities of the system available in the Windows 7 operating system environment after installation are:

Windows XP Mode

It is a virtual machine that emulates an XP environment for those programs that need it.

La interfaz

Se puede personalizar con nuevos temas, color de ventanas, imágenes de fondo, los sonidos del sistema y el protector de pantalla.

Soporte para pantallas multitáctiles

Ofrece soporte para pantallas multitáctiles y sensores de diversos tipos.

Centro de actividades para el control de Seguridad y Mantenimiento

Dispone de un nuevo control de cuentas de usuario.

Device Stage

Con el que se puede ver todos los dispositivos de hardware que están conectados con sus propiedades, añadir nuevos dispositivos, etc.

Soporte directo

Para varios monitores para tarjetas gráficas con salidas a múltiples monitores.

Grabación de acciones

Firewall

Bitlocker y Bitlocker To Go

AppLocker

EFS

Para el acceso a Internet

Grupo Hogar

The current boot system is called BDC store, which no longer uses the traditional boot.ini file to manage the boot menu. Instead, it has an online tool to modify boot parameters called bcdedit.exe; there is also a freeware graphical application that facilitates boot configuration called VistaBootPro. The BCD is hidden in binary encoding and can only be edited if your user is an administrator. It can be modified using the bcedit command or from the Startup and Recovery dialog box, which allows you to select the default boot operating system and change the wait time to select an option from the menu, or by running Msconfig.exe from the start bar.

We can consider that when we turn on the computer, the electrical current brings the components of the motherboard to life. Immediately, the microprocessor sends an order to the BIOS ROM chip (Basic Input/Output System), where the POST (Power-On Self-Test) routines or boot program are stored. Once the BIOS receives the order from the microprocessor, the POST begins to execute a sequence of tests, passing control to the MBR, which will direct to the Master Boot Record (boot sector of the hard drive) to continue with the computer's boot process.

Windows Server 2008 is the network server operating system from Microsoft. It is based on the Windows NT 6.1 kernel.

We can find the following available distributions of Windows Server 2008:

Windows Server 2008 Datacenter

Supports from 2 to 64 processors. It provides the ideal platform for virtualization solutions. Ideal for large organizations with heavy database access and a high number of transactions per second.

Windows Server 2008 Enterprise

Ideal for large corporate networks. Supports up to 8 processors. It offers the possibility of server clustering with up to 16 servers acting as a single server. It allows for reduced infrastructure costs through application consolidation, utilizing virtualization licensing rights.

Windows Server 2008 Standard

It incorporates enhanced virtualization and web capabilities. Ideal for medium and small businesses. It supports multiple processors. The limit for remote access connections and terminal services is 250.

Windows web server 2008.

This edition is designed as a specialized web server. It integrates with IIS 7.0 environments, ASP.NET, and Microsoft .NET Framework. It does not have domain-based tools or services other than those related to web hosting.

The number of licenses required, with the possibility of choosing between two types:

Per server

The server has a set number of licenses that will allow users to connect. Each time a user connects, a license is consumed, which will be released when the user disconnects.

Per user or device

Licenses are user-based. It allows connecting to networks where there are multiple servers. With that license, one can connect to any server on the network. A license is acquired for each user on the network.

In many cases, the installation of an application requires the purchase and registration of usage licenses. In Windows Server 2008, two types of licenses are distinguished:

The licenses specific to Windows Server 2008 for its network clients, decided and discussed during the installation process, are referred to as per server or per user/device.

The Terminal Services licenses (each of the clients of the Terminal Services must have a license).

1. Structure of a Computer System

This topic explains some basic definitions such as:

Computer science

Computer

Software

Programming language

Computers can be classified as

For general use

For specific use

Supercomputer

Mainframe computer

Mini computers

Microcomputers

It is the set of scientific knowledge and techniques that make possible the automatic processing of information by means of computers.

An electronic machine equipped with a large capacity memory and methods for processing information, capable of solving arithmetic and logical problems through the automatic use of registered programs.

It is the set of instructions that a computer must execute to perform a given task. These instructions belong to a specific programming language.

A program is a sequence of instructions or commands that allow a computer to process information known as input data to produce output information or results.

They run all types of applications.

They run applications with a single service purpose.

They process large amounts of information in a short time.

Also known as mainframes. Large and fast computers, they are capable of handling hundreds of users simultaneously, used to manage large communication networks, and support more programs than supercomputers.

Also known as mainframes. Large and fast computers, they are capable of handling hundreds of users simultaneously, used to manage large communication networks, and support more programs than supercomputers.

Also known as personal computers. These are computers for professional or personal use, and can be desktop or laptop. When connected to a network, they operate with software that functions as a workstation within a LAN.

3.2.1. Técnicas de administración de la memoria

Existen diferentes técnicas de administración o de gestión de memoria como son:

Memoria Virtual

Método que consiste en permitir que el tamaño conjunto del programa y sus datos sea mayor que la cantidad de memoria física disponible.

Paginación

Método que consiste en dividir la memoria física en zonas de tamaño fijo llamadas frames o tramas y los programas o espacio lógico en partes del mismo tamaño llamadas páginas. Cuando varios usuarios están ejecutando procesos en un mismo ordenador, éste se ve obligado a cargarlos en RAM, según el estado en el que se encuentre el proceso de cada usuario, la memoria se irá liberando o no.

Segmentación

Técnica similar a la paginación pero definiendo los bloques de memoria de tamaño variable. La información lógica del proceso se divide en distintos bloques lógicos denominados segmentos, donde cada segmento tiene información lógica del programa (datos y código) y de pila (stack).

Medida de la información

El bit es la unidad más pequeña y se representa por cero o uno. Ocho bits forman un byte, que es la unidad básica para representar caracteres en el sistema. Dado que los bits y bytes son muy pequeños para medir grandes cantidades de información, se utilizan múltiplos del byte, como el kilobyte (KB), megabyte (MB), gigabyte (GB), entre otros. La relación entre estas unidades se basa en potencias de 2, ya que los sistemas informáticos operan en base binaria.

Los ficheros son la estructura utilizada para alojar datos o instrucciones que se almacenan en soportes externos para poder ser procesada por el sistema mediante un determinado programa .

3.4. Controlar la organización de ficheros o archivos

Los sistemas de ficheros manejan dos tipos fundamentales de objetos:

Los ficheros regulares

Es una unidad lógica de memoria para almacenar datos que se identifica por un nombre extensión . Las características de los nombres de los ficheros dependen de los sistemas operativos, por ejemplo la indica el tipo de fichero que es, el atributo que caracteriza a cada fichero indicando que tipo de operaciones o usuarios pueden interactuar con él, etc.

Los directorios

Son contenedores o carpetas que sirve para almacenar archivos u otros directorios. La utilización de directorios permite una mayor organización de los ficheros dentro del disco. En casi todos los sistemas de fichero existe un directorio principal llamado raíz (root) que es el directorio que contiene todos los demás ficheros y directorios. La estructura de directorios suele ser jerárquica, ramificada o "en árbol".

Las principales operaciones que se suelen realizar con los ficheros en la mayoría de los sistemas son: crear, renombrar, abrir, copiar, buscar, leer, escribir, cerrar y borrar, las cuales van relacionadas con los permisos y derechos que tiene cada usuario para su uso. Las operaciones con los directorios, por ejemplo en Linux son: crear, borrar, abrir, cerrar, leer, cambiar de nombre, enlazar, desenlazar directorios.

3. Functions or Services of an Operating System

User Interfaces

It is the part of the operating system that allows communication with it, enabling the loading of programs, accessing files, and performing other tasks.

Resource Management

They are used to manage the hardware and network resources of a computer system, such as the CPU, memory, secondary storage devices, and input and output peripherals.

File Management

An information system contains file management programs that control the creation, deletion, and access of data and program files.

The OS in its design must provide the following capabilities

Task Management

It accepts tasks, manages how they are performed, and allocates resources to them. The task management programs of an operating system handle the execution of computing tasks for end users.

Support Services

The support services of each operating system will depend on the particular implementation we are working with.

Security Control

It provides security for the stored information and system users by managing permissions and users to prevent conflicts between different tasks.

3.1 Controling Processes

3.2 Control and Manage Memory

3.3 Control Peripheral Devices. Classification of Peripherals

3.4 Control File Organization

Some of the basic features or utilities of the system available in the work environment of the Linux Ubuntu operating system after being installed are:

Multi-user operating system.

Multitasking system.

Use of virtual memory.

Network structure formed by a central server.

Distribution for server or personal computer.

Hierarchical file system.

Two main components.

Kernel version is made up of three numbers:

They have several command interpreters.

Main version number.

Secondary version number.

In this case, if it is even, it indicates a stable version. While if it is odd, it indicates a beta version.

Current revision number.

The Bourne Shell.

It is the oldest. Developed by Steven Bourne. The prompt is represented by the character '$'.

The C Shell.

Derived from the BSD system. It was developed by Bill Joy.

The Korn Shell.

Developed by David Korn at Bell Labs.

The kernel.

The Shell.

An operating system is software made up of a set of programs that controls and interacts with the system, providing control over the hardware and supporting other programs, such as those that make up the so-called application software.

Operating system models

Monolithic Design

Layered Design

Virtual Machines

Client/Server Model

Microkernels

2.1. Components of an Operating System

2.1.2 Interprete de comandos. Programas útiles de un sistema operativo

The system consists of a single program made up of multiple routines or subprograms.

It is made up of a series of layers or rings that communicate with each other based on the functions they can perform.

It allows software to emulate operating systems, a machine, or a computer network.

The OS is organized as a set of autonomous modules, each of which provides a series of services to the others.

It consists of a kernel that provides minimal management of processes, memory, and also offers a layer of communication between processes.

4. Types of Operating Systems

Operating systems can be classified based on various parameters:

By their internal structure

Through this classification, we divide operating systems based on how the systems are designed during their creation.

According to the number of users

In this classification, the end user's perspective is taken into account.

According to the number of processes or tasks

According to the number of processes or jobs that can run at the same time.

According to the number of processors

En función de la cantidad de procesadores utilizados en el sistema.

According to the type of response

Se basa en las distintas formas en las que un sistema operativo utiliza los recursos

By the way of providing services

Monolithic

The system consists of a single program made up of multiple routines that can call one another.

Layered

The system is designed in a hierarchical structure that is divided into different levels.

Virtual Machine

The main advantage of this structure is that it allows the implementation of various types of operating systems on each virtual machine, presenting an interface to each process.

Client-Server

Processes can be both servers and clients. The operating system maintains communication between processes. It offers great flexibility regarding the final system services.

Single-User

The hardware resources and the software being used are available to a single user on a single computer, regardless of the number of processes or tasks the user may execute at the same time.

Multi-User

It allows multiple users to utilize the software and hardware resources of the same computer.

Single-Task

The computing system resources are assigned to a program until its execution is complete.

Multi-task

The operating system can execute multiple programs simultaneously as the CPU shares the microprocessor's usage time among the different running programs, allowing the computer to perform several tasks at the same time.

Single-Processor

The UCP has a single processor to serve the users.

Multiprocessor

The CPU is capable of handling multiple processors simultaneously, distributing its workload to increase processing power.

Batch Processing

Jobs are grouped into similar blocks or batches without any interaction between the user and the processes while they execute sequentially.

Time-Sharing Systems

The system is responsible for distributing processes based on an assigned time for using the processor or processors until completion.

Real-Time Systems

The response time is immediate for the request to execute a process.

Hybrid

These systems aim to be a blend of the two previous ones, seeking to combine the advantages of time-sharing and real-time systems.

Centralized Systems

It is a large computer (mainframe) that performs all the processing, and users connect to it through dumb terminals (without processing capability) that do not have memory or a processor.

Networked Systems

These systems communicate several computers with each other through some means of communication in order to share resources and system information.

Distributed Systems

It is a variant of the network system but integrates resources into a virtual machine in such a way that the user accesses them transparently without knowing where the resources are located; it allows distributing jobs, tasks, or processes among a set of processors.

9.Virtualization of operating systems

A virtual hypervisor (in English, hypervisor virtual machine monitor or machine monitor) is a virtualization platform that allows different operating systems to be used simultaneously.

The advantages of virtualization are as follows:

Run operating systems to 'test' them.

In this way, we can run an operating system that we want to test (Linux, for example) from our usual operating system (Windows, for example) without needing to install it directly on our computer.

Allows the installation of one or more operating systems on one.

Without being affected and being able to boot it simultaneously.

A disk file is used as a virtual partition.

Sharing resources and devices.

We achieve a virtual PC within the physical PC.

The virtual PC will boot up like any other program within the host operating system.

Have multiple operating systems to use 'programs that are not cross-platform.

To make demonstrations or use the guest system without having to remove the host system.

Hypervisors can be classified into two types:

System virtual machines

System virtual machines, also known as hardware virtual machines, allow the underlying physical machine to multiplex between several virtual machines, each running its own operating system. The layer of software that enables virtualization is called the virtual machine monitor or "hypervisor."

Process virtual machines

It runs as a normal process within an operating system and supports a single process. The machine starts automatically when the process to be executed is launched and stops when it finishes.

Different operating systems can coexist.

On the same computer, in solid isolation from one another, for example, to test a new operating system without the need to install it directly.

Instruction architecture.

That is something different from the actual machine. In other words, we can simulate hardware.

To consolidate servers.

This allows services that normally need to run on different computers to avoid interference, to run on the same machine in a completely isolated manner while sharing the resources of a single computer.

Virtualization is an excellent option.

Since current machines (laptops, desktops, servers) are often "under-utilized" (with large hard drive capacity, RAM, etc.), reaching usage levels between 30% and 60% of their capacity. By virtualizing, the need for new machines on an existing one allows for considerable savings in associated costs.