Computer Networks and Communication Fundamentals
Computer Processes and Communication
Defining Computer Processes
A computer process is a running program responsible for performing specific predefined functions.
Transmission vs. Communication
Transmission refers to the conveyance of signals to produce a telematic phenomenon. Communication, on the other hand, concerns the transport of information.
Communication Elements
- Sender: The element responsible for providing information.
- Receiver: The element that receives information from the sender.
- Channel: The
Data Link Layer: Protocols, Access Methods, and Frame Creation
Data Link Layer
Functionality
The data link layer facilitates data exchange using Protocol Data Units (PDUs) as frames. It provides two primary services:
- Access to upper layers via frames.
- Controlled data location and usage through media access control and error detection.
This layer encapsulates packets into frames and manages their placement and removal using media access control.
Sublayers
The data link layer comprises two sublayers:
- Logical Link Control (LLC): Identifies the network layer protocol using
Understanding FAT and EXT File Systems
File System Structures: FAT and EXT
FAT File System
Components and Roles
- Boot Sector: The first sector of the volume. Contains information about the file system’s size and structure, and information needed to boot MS-DOS.
- First FAT (File Allocation Table): A table where each entry corresponds to a cluster on the disk. It tracks which clusters are used by files and how they are linked together.
- Second FAT: A copy of the first FAT, providing redundancy in case of failure.
- Root Directory: Contains entries
Hardware and Software Components for Data Integrity
Hardware Devices for Safety Information: UPS, Disk Mirroring
Many systems provide hardware and software resources to multiple users. Therefore, the integrity of the information they contain and work with must be protected against physical shortcomings: power outages, heat, dust, electromagnetic fields, viruses, etc.
UPS (Uninterruptible Power Supply)
A UPS is a high-power device that acts as a bridge between AC power and the computer. It protects against voltage spikes and power cuts that can damage
Read MoreI/O System Organization and Performance
Part 2 – Interface Between Processors and Peripherals
I/O Organization (T.1)
Introduction (1.1)
A computer system comprises three subsystems: CPU, memory, and I/O. The I/O system facilitates data movement between external devices and the CPU-Memory tandem. It includes:
- I/O devices: These devices interface the computer with external peripherals, enabling user interaction (e.g., mouse, keyboard) and device-to-device communication (e.g., network, storage).
- Interconnections: These are the physical connections
Java Programming Examples: Array, Polymorphism, and Encapsulation
Java Programming Examples
1. Calculate Sum and Average of an Array
This program demonstrates how to calculate the sum and average of elements in an array.
package mypack;public class Array_demo { public static void main(String[] args) { int[] a = {1, 2, 3, 4, 5, 6, 7, 8}; int sum = 0; for (int i = 0; i < a.length; i++) { sum = sum + a[i]; } System.out.println("Sum: " + sum); System.out.println("Average: " + sum / a.length); }}