Operating System Fundamentals: Commands, Architecture, and Services
Operating System Concepts
1. Internal vs. External Commands
Internal commands are built into the command interpreter (like Command Prompt in Windows or Shell in UNIX) and are always loaded into memory when the operating system starts. They execute directly without requiring an external file and are faster. Examples in Windows include DIR, CLS, COPY, and DEL. In UNIX/Linux, examples are CD, PWD, ECHO, and EXIT.
External commands are separate executable files stored in the operating system. They are
Read MoreCore Concepts in Computer Graphics and Virtual Reality
Understanding Pixels, Resolution, and Back-Face Detection
A pixel (short for picture element) is the smallest unit of a digital image or display screen. It represents a single point in a raster image and has a specific color and intensity.
Resolution refers to the number of pixels in an image or display, usually written as width × height (e.g., 1920×1080). Higher resolution means more pixels, which leads to sharper and more detailed images.
Back-Face Detection Algorithm
Back-face detection is a hidden
Read MoreEssential Computer Science Concepts and IT Definitions
System Fundamentals
A system is a set of interrelated parts working together to achieve a common goal.
System Components
- Environment
- Inputs
- Process
- Outputs
Information Systems
An Information System (IS) is a set of elements and procedures designed to improve data processing and elaborate reports, facilitating decision-making to achieve beneficial goals.
Data Processing
Data Processing is a series of elementary operations performed on data to produce results.
Process Flow: Reception → Storage → Processing
Read MoreOperating System Fundamentals: Core Concepts & Components
Understanding Operating Systems
An operating system acts as an intermediary between a user of a computer and the computer hardware.
Scheduling Challenges
Scheduling involves managing machine time. For example, a user might sign up for an hour but finish their job in 45 minutes. This would result in wasted computer idle time. Conversely, a user might run into the problem of not finishing their job in the allotted time.
Operating System Types
- Serial Processing
- Batch Processing
- Multitasking or Time-Sharing
Understanding File System Structure and Operations
File System Structure
A file system structure typically consists of:
- Boot Block: Contains boot information.
- Super Block: Contains metadata about the file system.
- Inode Table: Contains inode structures for each file.
- Data Blocks: Store file data.
- Directory Blocks: Store directory information.
Key Components
- Inodes: Contain file metadata (ownership, permissions, location).
- File Descriptors: Identify open files.
- Directory Entries: Map file names to inodes.
File System Operations
- Create: Create a new file or directory.
Core Computer Concepts: Hardware, Software, Networking
Understanding Computers and Data
Computers are machines capable of processing information and performing many different operations. They come in various forms:
- Types of Computers:
- Personal Computers (PCs)
- Notebooks (Laptops)
- Servers
- Personal Digital Assistants (PDAs)
Data Measurement Units: Bits & Bytes
These units are used to measure the amount of information a device can hold.
- Bit: The minimum unit of information. It’s a binary digit (0 or 1).
- Byte: A fundamental unit consisting of 8 bits.
- Kilobyte (