Computer Basics and Components

Computer Basics

• A computer is an electronic device operating under stored instructions, accepting data (input), processing it according to rules, producing information (output), and storing it for future use.
• Digital computers perform five functions: they take data as input, store data and instructions, process data into useful information, generate output, and control all steps.
• Computers consist of hardware and software.
• Input devices translate data from human-understandable forms into a computer's language; a keyboard and mouse are common examples.
• The most common keyboard is the QWERTY keyboard, which generally has 104 keys.

Computer Components

• Hardware consists of physical elements like monitors, mice, keyboards, data storage, hard drives (HDD), and system units (graphic cards, sound cards, memory, motherboard, chips).

Central Processing Unit (CPU)

• A CPU, the computer's brain, manages all functions and processes and is crucial for computing power.
• The CPU is comprised of the Arithmetic Logic Unit (ALU), Control Unit (CU), and Registers.
• The ALU executes arithmetic/logical operations (addition, subtraction, multiplication, division) and compares numbers/characters.
• The CU controls and coordinates computer components.
• Registers store data for immediate execution, serving as a "very fast storage area."

Primary Memory

• RAM (Random Access Memory) temporarily stores data for immediate processor access.
• It's volatile, meaning data is lost when power is off, and allows random data access.
• ROM (Read Only Memory) stores data permanently, retaining data regardless of power and restricts data modification

Secondary Memory

• This memory stores data and programs permanently, retaining data after power is off.
• Hard drives (HD) store and provide quick access to large amounts of data.
• Optical disc drives (ODD) use laser light to read/write data on optical discs; common types include CDs (up to 700 MB), DVDs (up to 8.4 GB), and Blu-ray discs (up to 50 GB).
• Flash disks use flash memory chips, emulating disk storage structure.

Memory Comparison

• RAM memory is smaller (500 MB-6 GB typically) than hard drive storage (80 GB-1000 GB typically).
• RAM is temporary storage that disappears on power loss; a hard disk is permanent storage, retaining data unless deleted.

Output Devices

• These communicate processed information into a human-readable form.
• Basic monitor types include Cathode Ray Tube (CRT), Liquid Crystal Displays (LCD), light-emitting diode (LED).
• Printer types include laser printers, ink jet printers, and dot matrix printers.

Software

• Software includes organized data and instructions divided into system software (for basic, non-task-specific functions) and application software (for specific user tasks).
• System software manages hardware, functioning as a unit with utilities like disk formatters and device control software.
• Application software accomplishes specific tasks, consisting of single programs, software packages, or software suites.

Software types Comparison

• System software is used for digitally stored data like computer programs; examples include Microsoft Windows, Linux, Unix, Mac OSX, and DOS.
• Application software perform specific tasks; examples include Opera, Microsoft Word, Microsoft Excel, MySQL, Microsoft PowerPoint and Adobe Photoshop

Measurement Units

• A bit (binary digit) is the basic unit of computer data storage, representing ones and zeros.
• Storage units include: Kilobyte (KB, 1024 bytes), Megabyte (MB, 1024 kilobytes), Gigabyte (GB, 1024 megabytes), Terabyte (TB, 1024 gigabytes).
• CPU speed is measured in Hertz (Hz), representing CPU cycles per second and is known as Computer Speed.
• Speed measurements include: 1 Hz (1 cycle per second), 1 MHz (1 million cycles or 1000 Hz), 1 GHz (1 billion cycles or 1000 MHz).

Computer Classification

• Computers are generally classified by size and power:
• Personal computers: Small, single-user computers with a microprocessor, keyboard, monitor, and storage.
• Workstations: Powerful, single-user computers like personal computers but with a better monitor and a higher-quality microprocessor.
• Minicomputers: Multi-user computers supporting 10 to hundreds of users simultaneously.
• Mainframes: Powerful multi-user computers supporting many hundreds to thousands of simultaneous users.
• Supercomputers: Extremely fast computers executing millions of instructions per second.

Laptops and Smartphones

• Laptops: Battery/AC-powered portable computers that offer similar functions to desktop computers.
• Netbooks: Portable laptops, cheaper but less powerful, suited for email and internet.
• Mobile Devices: Handheld, portable computers, more powerful and capable of various tasks.
• Tablet Computers: Portable, touch-sensitive computers without keyboards or touchpads, designed for consuming media.
• Smartphones: Mobile phones designed to run apps and serve for web browsing, watching videos, and reading e-books.

Data, Information and Knowledge

• Data: Unorganized facts and figures without context.
• Information: Data processed and contextualized for relevance and purpose.
• Knowledge: Applying know-how and understanding.

Human Mind Content

• Data: Symbols
• Information: Processed data providing "who," "what," "where," "when" answers.
• Knowledge: Applied data and information giving "how" answers.
• Wisdom: Evaluated understanding.

Computer Characteristics

• Speed: Capable of processing millions of instructions per second.
• Accuracy: Provides high accuracy, even up to 10 decimal places
• Diligence: Maintains consistent speed and accuracy over extended use.
• Storage Capability: Can store and retrieve large amounts of data, temporarily (primary memory) or permanently (secondary storage).
• Versatility: Can perform different tasks, but reliant on programming instructions.

Computer Viruses

• Viruses attach to actual programs, running alongside and replicating or causing damage.
• Email viruses attach to emails and automatically mail themselves, sometimes launching upon viewing.
• Trojan horses claim to be beneficial but cause damage when run.
• Worms exploit networks and security holes for replication.
• Protecting data involves installing/updating anti-virus software, using on-access scanners, scanning new files, exercising caution with community files/links, and backing up data.