Operating Systems: Functions, Components, and Network Basics

Functions of Operating Systems

Processor Management

The Operating System distributes the processor between different programs.

Random Access Memory Management

The Operating System coordinates the memory space that each application has. When physical memory is insufficient, the Operating System can create a "virtual memory" on the hard disk.

Input/Output Management

The Operating System allows the unification of program access to material resources through controllers.

Execution of Application Administration

The Operating System is responsible for ensuring that applications run smoothly.

Authorization Management

Guarantees that resources are only used by programs and users with the corresponding authorizations.

File Management

The Operating System manages reading and writing in the file system.

Components of Operating Systems

The Kernel or Core

Represents the basic operations of the Operating System.

The Command Line

Enables communication with the Operating System through a control language.

The File System

Allows the registration of files in a tree structure.

The Hard Disk

Consists of one or more platters spinning at high speed inside a metallic box. Over each platter is placed a read/write head.

Characteristics

• Interface
• Average access time
• Average seek time
• Read-Write time
• Average latency
• Rotation speed
• Transfer rate
• Cache memory
• Landz

The Solid-State Drive (SSD)

A solid-state storage device that uses integrated circuit assemblies as memory to store data persistently. They have many advantages compared to hard disks.

Types of Networks

According to Size or Coverage Area

• Personal Area Networks (PAN): A mobile phone with a computer
• Local Area Networks (LAN): For a house
• Metropolitan Area Networks (MAN): For a city
• Wide Area Networks (WAN): Cities, countries, or continents

According to Level of Access or Privacy

• Internet: Public access
• Intranet: (Web, email, FTP…)
• Extranet: Private network

According to Functional Relationship

• Client-Server
• Peer-to-Peer or P2P networks

The Basics of Networks

Communication

The process that carries a message from a sender through a channel to a receiver.

Protocol

The language and set of rules for which sender and receiver communicate.

Private IP Address

Consists of 4 numbers, with values from 0 to 255.

Public IP Address

The IP address visible from the Internet.

Gateway

The IP address through which the local network sets off towards the exterior, either another network or the Internet.

Network Mask

Similar to the IP address. It specifies which part of the IP address belongs to the computer and which part to the subnetwork.

DNS

IP addresses are hard to remember.

MAC Address

Consists of 6 hexadecimal pairs of numbers.

Port

Interface to communicate with a program through a network.

Malware

A program that tries to infiltrate or harm a computer.

Virus

Malware that alters the normal performance of computers.

Worms

Spread by themselves without being executed by a person.

Trojans

Programs that hide a non-derived function in a normal program.