Computer Hardware, Software, and Networks

Posted on Mar 30, 2025 in Technology

Computer Hardware

Data Storage

  • Floppy Disk: A thin, flexible plastic disk coated with magnetic material, historically used for data storage.
  • Hard Disk: A rigid, magnetic disk made of hard plastic or metal, used for long-term data storage.
  • CD-ROM: An optical disc that uses a laser to read data.
  • DVD: An optical disc with a higher storage capacity than a CD-ROM, also using a laser for data reading.
  • Magneto-Optical Disk: A disk that uses both magnetic and optical technologies for data storage.
  • Flash Memory: A non-volatile semiconductor memory made of silicon and germanium, commonly used in USB drives, memory cards, and solid-state drives.

Computer Networks

Network Types

  • PAN (Personal Area Network)
  • LAN (Local Area Network)
  • MAN (Metropolitan Area Network)
  • WAN (Wide Area Network)
  • Public and Private Networks

Network Topologies

  • Bus
  • Tree
  • Star
  • Ring

Network Components

  • Network Interface Card (NIC)
  • Router
  • Switch
  • Bridge
  • Repeater
  • Hub
  • Modem (Analog and Digital Signals)

Electrical Signals

  • Electrical Signal: Converts mechanical energy into electrical energy.
  • Analog Electrical Signal: Resembles real-world phenomena; its amplitude and period can be analyzed.
  • Digital Signal: Artificial signals that represent data in discrete values.

Analog-to-Digital Conversion: Samples are taken from the analog signal and assigned binary values. The more samples taken, the better the digital representation of the analog signal.

Operating Systems

Types of Operating Systems

  • Single-Tasking: Only one program can run at a time.
  • Multitasking: Allows multiple programs to run concurrently.
  • Real-Time: Provides immediate responses to instructions.
  • Single-User: Supports one user at a time.
  • Multi-User: Allows multiple users to access the system simultaneously.

Evolution of Operating Systems

  • MS-DOS (Microsoft Disk Operating System): A single-user, single-tasking system released in 1981.
  • Windows 3.x: A graphical user interface built on top of MS-DOS.
  • Windows 95: A multi-user, multitasking operating system with networking capabilities.
  • Windows 98: An improved version of Windows 95 with enhanced connectivity and security.
  • Windows NT: A multi-user, multi-tasking operating system released in 1993.
  • Windows 2000: An improved version of Windows NT.
  • Other Operating Systems: Windows Vista, Unix, Linux, macOS.

File Systems

File System Functions

A cluster, consisting of one or more sectors (512 bytes each), is the basic unit of storage. Each cluster has a unique address and cannot be shared by different files. Fragmentation occurs when unoccupied spaces are left between files.

Types of File Systems

  • FAT (MS-DOS/Windows 95): Cluster size 2-35 KB, maximum partition size 2 GB.
  • FAT32 (Windows 95/98/XP): Cluster size 4-32 KB, maximum partition size 2 TB.
  • NTFS (Windows 2000/XP/NT): Cluster size 0.5-4 KB, maximum partition size 2 TB.
  • Ext2/Ext3 (Linux): Cluster size 1-4 KB, maximum partition size 4 TB.

Disk Partitions

Hard disks can be divided into partitions, which can host operating systems, applications, and data. The Master Boot Record (MBR) in the first sector of the hard disk contains information about the number and arrangement of partitions. A maximum of four primary partitions can be created.

Partition States

  • Active: Contains the operating system used for booting.
  • Available/Unallocated: Unformatted space available for use.