# CIS105: Computer Applications & Information Systems Lect. 3

## Chapter 3: Computer Hardware

### 3.1: Technical Terminologies

-   **System Unit**: Main body of the computer that contains a motherboard.
-   **Motherboard** (AKA Circuit Board): Main component of a system unit; a compleex array of electronics that connect and help different components of the computer communicate with each other.
    -   PC: Motherboards, Mac; Logic Boards
-   **Chassis** (AKA Case or Box): Case to enclose the main components of a computer
-   **Microprocessor**: The brains of the computer
    -   **Central processing unit (CPU)**: Interprets program instructions and processes data by performing arithmetic and logical operations.

### 3.2: Central Processing Unit (CPU)

-   Speed is directly, but not solely, related to the CPU
-   Measured in Clock Rate
    -   The number of cycles per second, that a computer can perform its most basic task
-   RSIC (Reduced Instruction Set Computer): Many chips encased into one chip
-   Bus Lines; Pathways that transfer data and power between components inside of a computer.

| Architecture Diagram of CPU                                                                                                      | Actual CPU Image                                                                                               |
| -------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------- |
| ![Architecture of the central processing unit (CPU) - Computer ...](https://computersciencewiki.org/images/1/1a/Cpu_diagram.png) | ![What Is a CPU? a Guide to Your Computer's 'Brain'](https://i.insider.com/60402d8eb46d720018b04c1f?width=700) |

### 3.3 Power Supply Unit (PSU)

-   Supplies electricity
-   Converts 100-120 volts or 220-240 volts of **alternating current (AC)** to a lower voltage direct current (DC) that can be used by the internal components of the system unit
-   Different currents used in different parts of the world.

### 3.4: Primary and Secondary Storage

-   **Primary**: The workbench
    -   Random Access Memory (RAM): Primary storage
-   **Secondary**: The storage for all your tools and supplies
    -   Hard Drive: Secondary storage
-   ROM Chips (Read-Only Memory): Preprogrammed chips that serve specialized internal tasks. No human intervention
    -   AKA Firmware

#### 3.4.1: Secondary Storage Contd.

-   Internal vs. External Storage
-   Hard Drivers vs. Solid State Drivers (SSDs)
-   Impractical for a computer to be stand-alone
-   Important to consider business needs
    -   Bad IT can make or break a business

### 3.5: Binary Number System

-   Computer only understands one language: Machine code or machine language

-   1 or 0 (on or off)

-   1s or 0s are referred to as bits (short for binary digits)

-   8 bits become a byte

    -   Byte 8 bits
    -   Kilob

-   American Standard Code for Information Interchange (ASCII): The coding scheme that most microcomputer use to represent bytes.

    -   | Name      | Equal To          | Size (In Bytes)                           |
        | --------- | ----------------- | ----------------------------------------- |
        | Bit       | 1 Bit             | 1/8                                       |
        | Nibble    | 4 Bits            | 1/2 (rare)                                |
        | Byte      | 8 Bits            | 1                                         |
        | Kilobyte  | 1024 Bytes        | 1024                                      |
        | Megabyte  | 1, 024 Kilobytes  | 1, 048, 576                               |
        | Gigabyte  | 1, 024 Megabytes  | 1, 073, 741, 824                          |
        | Terrabyte | 1, 024 Gigabytes  | 1, 099, 511, 627, 776                     |
        | Petabyte  | 1, 024 Terabytes  | 1, 125, 899, 906, 842, 624                |
        | Exabyte   | 1, 024 Petabytes  | 1, 152, 921, 504, 606, 846, 976           |
        | Zettabyte | 1, 024 Exabytes   | 1, 180, 591, 620, 717, 411, 303, 424      |
        | Yottabyte | 1, 024 Zettabytes | 1, 208, 925, 819, 614, 629, 174, 706, 176 |

### 3.6: Peripheral Devices

-   Input v. Output
-   Input device: keywords, mice, touchpad, stylus, speakers, microphone, digital camera, etc/
-   Optical Character Recognition (OCR): Converting printed text to digital text
-   Radio Frequency Identification (RFID): An input mechanism that can be used to label a product for identification and have the product's information transmitted through radio waves.

### 3.7: Output Devices Contd.

-   Monitor: A series of transistors that translate machine code into text and images./
-   Pixels: A single dot on a graphic or text image
-   Resolution: The number of pixels inside a defined dimension on a monitor, commonly referred to as **dots per inch (dpi).**
    -   Resolution is the most important feature of a monitor.