Chapter 2: Hardware

• personal computer only has about a dozen parts

• bulk of the machine: system unit and motherboard

• system unit- case that houses the computer’s critical parts, such as its processing and storage devices. This part has historically been available in two forms: a horizontal desktop and a vertical tower.

• Drive bays. Tower-based system units include several drive bays that hold the internal storage devices of your computer, such as the hard drive and the DVD drive.

• Power supply. This component is responsible for providing power to all the parts inside the system unit. When you plug a power cable into the back of your tower, you are essentially connecting it to the power supply. If you purchase a power supply separately, be sure to note the number of watts, which determines how many devices it can provide power to.

• Without proper cooling, a computer could overheat and malfunction. Dust is an enemy of both electronic components and fans, so if necessary, use a can of compressed air to clean your computer periodically.

• The motherboard is the largest circuit board in a personal computer. It contains a variety of slots, connectors, and plugs for hooking up all the other parts of a computer, from the storage devices on the inside to the keyboard and monitor on the outside.

• All data travels through wires located throughout the motherboard’s surface, and several chipsets act as traffic directors for all this data.

• Nevertheless, some users may still choose to purchase add-on circuit boards known as expansion cards in order to improve the performance of their system’s video or sound.

• sides of laptop computers. The most popular of these plugs is the small, rectangular USB port, which is used to connect almost all of today’s external devices.

• central processing unit (CPU), or microprocessor, is the main processor of a computer. It is responsible for organizing and carrying out instructions to produce a desired output. It can perform a diverse number of operations, from finding a name in your smartphone’s contacts to handling the complex calculations required by today’s engineers. For this reason, it is often nicknamed "the brain" of the computer.

• For mobile devices, you will find companies such as Apple, Qualcomm, and Texas Instruments producing ARM-based processors. These types of chips generally produce less heat and use less power—characteristics that are crucial for mobile devices.

• Most of today’s microprocessors have several processors, or cores, inside a single chip. A dual-core processor can be twice as efficient as a traditional processor, given that it can handle twice the work at any given moment. Many of today’s processors have more than two cores, with four, six, and even eight becoming common.

• CPU’s clock rate measures the frequency or speed at which it can process instructions. This speed is measured in hertz,

In a computer, memory is a general term for electronic chips that store data and program instructions that can be accessed quickly by the CPU. Many users confuse memory and storage, especially now that we have storage devices called "memory cards." This will all be cleared up in the next few pages as we contrast the various memory and storage technologies. In this section, we will be exploring several types of memory used in personal computers, starting with the one you are likely familiar with already: RAM.

RAM

The most noticeable type of memory for a user is the temporary workspace known as random access memory (RAM). Whenever you actively work on something using your computer, that work is temporarily stored in RAM. For example, right now you may have a résumé or school paper that is stored somewhere on your computer. When you open this document in Microsoft Word to work on it, both the Word program and the document will be copied into RAM. When you save the document and close Word, it is removed from RAM but remains safe on a storage device (see Figure 2.1).

RAM is considered to be volatile because its contents change often and will disappear if the computer loses power or is restarted. This is one of the fundamental differences between this temporary memory and your more permanent storage devices/media such as hard drives, DVDs, and SD cards. Let us now turn to a few details you should know about RAM:

• Memory modules. RAM consists of a set of chips mounted on a small circuit board called a memory module. These modules are then inserted into special slots on the motherboard. This is important to know when purchasing a computer, because the number of available slots can affect your ability to add more RAM. Computers typically have anywhere from one to four slots.

• Type and speed. There are a large variety of RAM types and speeds. Consider the following example: DDR3 1333. The first part, DDR3, indicates the type of RAM. The 1333 represents the speed at which it can transmit data to the CPU. The main reason to know these details is to ensure that you purchase the correct RAM if you are planning on upgrading your computer.

• Capacity. Each RAM module can hold a specific amount of information, typically one to eight gigabytes. The higher your overall capacity, the more programs and files you can open and work on at once. This allows you to have a fast and smooth experience when switching from one program or browser tab to another.

OTHER TYPES OF MEMORY

Although RAM is the most popular type of memory, a modern computer would not function properly without a few other types of memory.

• Read-only memory (ROM) is a small chip that contains non-volatile, device-specific information. The instructions on this chip are known as firmware, and they handle a computer’s basic functions when it is powered on. On PCs, these instructions are commonly known as the BIOS. Currently, the "read-only" portion is a bit misleading, as most of these chips (now known as flash memory) can be electronically reprogrammed via a process called flashing. This allows for a variety of activities, from receiving an important update from your computer manufacturer to installing a customized operating system on Android mobile devices.

• Cache refers to a form of high-speed memory that stores a small, frequently used set of instructions and data. It is located inside modern CPUs.

• Virtual memory is not actual memory, but rather a portion of your hard drive that is being used as RAM. Your operating system uses this tactic when your opened programs and files do not fit into RAM. It takes portions of them and, without you noticing, moves them onto your hard drive. The only time you may be aware of it is when you experience a tiny delay in switching from one open program to another that had been temporarily placed in virtual memory. This is because accessing RAM is much faster for a computer than accessing your storage devices.

• As you have already learned, the purpose of storage is to hold programs and data permanently, even when the computer is turned off. The devices that can read, write, and erase data are called drives. The physical locations where things are stored are known as storage media. For example, your DVD discs are known as storage media, while the device that you insert them into is the drive. Let us now explore all of the various storage devices used by modern computers, as well as the units of measurement that describe their capacity.

  STORAGE UNITS

  The most fundamental unit of computing is the bit, which is typically represented as an on (1) or off (0) value. This is because digital, electrical devices can truly only “understand” the concept of being on or off. Consider for a moment that you are a wire (or bus) on a circuit board. Essentially, all that could possibly make sense to you is that there is electricity flowing through you at a given moment or that there isn’t. It is the sequence or order of these bits that is interpreted and processed into meaningful information. Many storage devices also use this 0 and 1 system to remember all types of information, from letters to colors.

  When it comes to describing a computer’s storage or memory, we commonly use the unit known as the byte, which is simply a collection of eight bits. The eight is significant because it is the amount of space required to store a single character, such as a letter or number. In modern computing, our files and programs are so large that it is helpful to use terms such as kilobyte (KB), megabyte (MB), gigabyte (GB), and terabyte (TB) to describe the values (see Table 2.1). In a world dominated by computers, it is crucial that you memorize these storage units much like you did inches and feet when you were young.

  Table 2.1 MEMORY AND STORAGE UNITS

  Unit	Approximate Value	Actual Value (bytes)
  Kilobyte (KB)	1,000	1,024
  Megabyte (MB)	1,000 KB	1,048,576
  Gigabyte (GB)	1,000 MB	1,073,741,824
  Terabyte (TB)	1,000 GB	1,099,511,627,776

In the 1940s, when electronic computers were beginning to appear, researchers realized that a computer would not be able to remember or store anything if it relied solely on electrical components. With a loss of power, every component would lose its charge and all data would be lost. The development of magnetic storage allowed data to be represented by magnets, which can hold their position or pattern to represent 0's and 1's without electricity. The following are some examples of magnetic storage devices:

• The hard drive (also known as the hard disk) is the primary storage device of a personal computer. While most use magnetic disks, some may use solid state technology, which will be discussed later in this section. Practically all desktop and laptop computers have an internal hard drive. You can also buy an external hard drive to store additional information or make copies of your irreplaceable data. These external drives are very portable and typically connect to the USB port on a computer. Both types of hard drives are currently capable of storing a few terabytes of data.

• Tape drives, which use magnetic tape to store data, are popular for organizations that have large quantities of information to back up or archive. You might find these drives organized into giant tape libraries that can hold thousands of terabytes of archived information.

• 💿 What is optical storage?

  • Uses lasers to read and write data on discs.

  • Data is stored by changing how reflective parts of the disc are.

  📀 Types of Optical Discs

  CD (Compact Disc)

  • Stores up to 700 MB.

  • Mostly used for music.

  DVD (Digital Versatile Disc)

  • Stores 4.7 GB or 8.5 GB.

  • Used for movies and software.

  Blu-ray Disc (BD)

  • Stores 25 GB or 50 GB.

  • Used for HD movies and modern video games.

  BD-XL

  • Stores 100+ GB.

  • Uses extra layers to hold more data.

  🧠 Easy Way to Remember

  CD → DVD → Blu-ray → BD-XL
  ⬆ Storage gets bigger each step!

  • CD = 700 MB

  • DVD = up to 8.5 GB

  • Blu-ray = up to 50 GB

  • BD-XL = 100+ GB

  🔥 Recording Terms

  ROM

  • Read only.

  • Can't change what's on it.

  -R or +R

  • Can be written to once.

  -RW, +RW, or -RE

  • Can be written, erased, and reused.

  Burning

  • The process of recording data onto a disc.

• 💡 What is solid state storage?

  • Uses flash memory chips (not magnets or lasers)

  • Has no moving parts

  • Stores data permanently even without power

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  🚀 Why it matters

  • Much faster than hard drives and optical discs

  • Smaller and lighter

  • Uses less power

  • Perfect for phones, laptops, and portable devices

  • More expensive, but prices are dropping

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  📱 Main Solid State Devices

  USB Flash Drive

  • Small stick that plugs into a USB port

  • Used to transfer or store files

  Memory Cards (SD cards)

  • Used in phones, cameras, tablets

  • Types: SD, miniSD, microSD

  • Can be removed and reused

  Solid State Drive (SSD)

  • Replaces or improves traditional hard drives

  • Can be internal or external

  • Very fast storage

  • Sometimes used with a hard drive (hybrid system)

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  🧠 Easy Summary

  • Solid state = flash memory + no moving parts

  • Hard drive = slower + moving parts

  • SSD = faster version of storage

  • USB + SD cards = portable storage

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  ⭐ Most Likely Test Questions

  1. What does solid state storage use?

     • Flash memory chips

  2. What is the biggest advantage of solid state storage?

     • Speed (very fast)

  3. Why are SSDs better than hard drives?

     • No moving parts + faster + uses less power

  4. Name 2 solid state devices:

     • USB flash drive, SD card, SSD

  5. What does an SD card do?

     • Stores data in phones, cameras, and tablets

💡 What are input devices?

• Devices that send data into the computer

• Convert things like words, sounds, and commands into digital data

⌨ Keyboard (Main Input Device)

• Main tool for typing letters and numbers

• Almost all computers have one

Types of Keyboards:

• Wired keyboard → connects with USB cable

• Laptop keyboard → built into laptop

• Touchscreen keyboard → phones and tablets

• Wireless keyboard → uses Bluetooth, no cable

• Ergonomic keyboard → shaped to reduce hand/wrist strain

• Keyboard cover → thin cover + keyboard for tablets

🧠 Ergonomics (Important Word)

• Design of objects for comfort and safety

• Helps prevent pain and injury

• Example: keyboards, chairs

🔑 Categories of Keys

• Keyboards differ between devices (Windows, Mac, laptops)

Important Keys:

• Windows key (Windows computers)

• Command key (Mac computers)

• CTRL + ALT + other keys

⌨ Keyboard Shortcuts:

• Key combinations that do actions quickly

• Example:

  • Save file

  • Copy/paste

  • Move cursor

👉 Faster than using a mouse

What is a scanner?

• A device that uses light (optical technology) to turn physical things into digital data

• Converts paper, images, or codes into computer format

📄 Types of Scanners

🗂 Document Scanners

• Scans many pages quickly

• Used by businesses to go paperless

• Can scan dozens of pages per minute

• Uses OCR (Optical Character Recognition) to turn images into editable text

📷 Flatbed Scanners

• Has a glass surface

• Scans photos, books, papers, objects

• Some have a document feeder (auto scans multiple pages)

• Often built into printers

📦 Barcode Scanners

• Reads barcode lines on products

• Used in stores and inventory

• Helps with checkout and tracking items

🔳 QR Codes

• Square codes made of dots and patterns

• Scanned with phone camera

• Can open websites or links instantly

📡 RFID Scanners

• Use radio waves to read tiny chips (RFID tags)

• Can scan from a distance

• Used for:

  • Toll roads

  • Inventory tracking

  • Pet identification chips

• NOT GPS (doesn’t track location)

📱 Scanner Apps

• Use your phone camera

• Turn documents into digital files (PDFs)

• Great for receipts and papers on the go

🧠 Easy Summary

• Scanners turn real-world objects → digital data

• Document + Flatbed = paper scanning

• Barcode + QR = product/code scanning

• RFID = fast wireless scanning

• Apps = phone-based scanning

⭐ Most Likely Test Questions

1. What does a scanner do?

   • Converts physical objects into digital data

2. What is OCR used for?

   • Turning scanned text into editable text

3. What type of scanner is used in stores?

   • Barcode scanner

4. What is an RFID scanner used for?

   • Reading tags using radio waves

5. What is a QR code used for?

   • Opening links with a phone camera

6. What is a scanner app?

   • A phone app that scans documents into digital files

🎤 Microphones

• Capture sound (voice/audio) and send it to the computer

• Built into laptops/phones, external on desktops

💡 Main uses:

• Voice calls (Zoom, internet calls)

• Recording audio for videos

• Speech recognition (computer understands your voice)

🗣 Speech recognition examples:

• Siri, Google Assistant, Cortana

• Smart speakers (Amazon Echo)

• Used for voice commands instead of typing

📷 Digital Cameras

• Capture photos and videos

• Found in phones, tablets, and standalone cameras

💡 Key facts:

• Storage depends on:

  • Megapixels (image detail)

  • Storage space

• More megapixels = better quality but larger file

• Front camera = lower quality than back camera

🎥 Video Cameras

• Record live video

• Can be built into devices or external

Types:

• Webcams → used for video chats (Zoom, Teams)

• Camcorders → high-quality video recording

• Security cameras → surveillance, remote viewing

• Gaming cameras → track movement and facial expressions

💡 Key term:

• Videoconferencing = online meetings using video

📺 TV Tuners

• Let computers receive TV signals

• Can be internal cards or USB devices

💡 Uses:

• Watch TV on a computer

• Record shows like a DVR

• Use antennas to get free local channels

🧠 Easy Summary

• Microphone = sound input

• Camera = photos/videos

• Webcam = video chat camera

• TV tuner = brings TV into your computer

• Speech recognition = computer understands voice

🎮 Game Controllers

• Main input device for video games

• Usually wireless and held in both hands

💡 Key features:

• Buttons → actions (jump, shoot, etc.)

• Analog sticks → movement control

• Some have motion sensors → detect movement

🧠 Example:

• Nintendo Wii → swinging controller acts like real-life motion (tennis, golf)

🧬 Biometrics (Very Important Term)

• Uses the human body for identification

• Used to unlock devices or verify identity

💡 Why it’s used:

• Faster and easier than passwords

• More secure

🔐 Types of Biometrics

👆 Fingerprint scanners

• Reads unique finger patterns

• Used for unlocking phones/laptops

😊 Facial recognition

• Scans face shape and features

• Used on phones and in security systems

👁 Other biometric types:

• Iris (eye scan)

• Hand shape

• DNA patterns

⚠ Important Note

• Biometrics usually stores data patterns, NOT actual photos

🧠 Easy Summary

• Game controller = plays games

• Biometrics = uses your body to identify you

• Fingerprint + face = most common biometric inputs

💻 What is output?

• Output = results from the computer

• Example: images, text, sound

💻 Monitors (Main Output Device)

• Displays text and images

• Screen is made of tiny dots called pixels

💡 Key Terms

• Pixel → tiny dot that makes up the screen image

• Resolution → number of pixels (ex: 1920 × 1080)

• Size → measured diagonally in inches

• Aspect ratio → screen shape (usually 16:9)

• Response time → how fast pixels change (lower = better for gaming)

• Contrast ratio → difference between black and white (higher = better)

• Viewing angle → how far you can look from the side before image fades

💻 Types of Monitors

💡 LCD

• Uses liquid crystals + backlight

• Controls pixels with electricity

💡 LED (newer, better)

• Uses LED lights for backlighting

• Thinner, brighter, more energy efficient

• Better contrast and speed

👉 Most modern screens = LED

🎮 Video Cards (Graphics Cards)

• Sends images from computer to monitor

• Helps control graphics quality

💡 Key parts:

• GPU → processes images and video

• Video memory (VRAM) → stores graphics data

💡 Important:

• Better GPU = better gaming and video performance

• Used for gaming, editing, graphics work

🔌 Connectors (How monitors connect)

• VGA → old, analog (blue plug)

• DVI → early digital standard

• HDMI → modern (video + sound)

• DisplayPort → high-performance modern connector

🔊 Computer Sound Systems

• Most computers have:

  • Microphone (input)

  • Speakers (output)

  • Sound card/processor

• Used for:

  • Music

  • Videos

  • Calls (videoconferencing)

  • Multimedia creation

🔊 Speakers (Output Device)

• Play sound from the computer

• Can be:

  • Built-in (laptops, monitors, phones)

  • External (surround sound systems)

  • Headphones/headsets

💡 Key idea:

• Speakers = sound output

• Headphones = private listening

🎧 Sound Card (Audio Processor)

• Converts sound between:

  • Analog → Digital (recording)

  • Digital → Analog (playback)

💡 What it does:

• Takes your voice from microphone and turns it into data

• Sends computer sound to speakers/headphones

💡 Important note:

• Many computers now have sound cards built into the motherboard

• Separate sound cards = used for high-quality audio or professionals

🎵 Sound Editing Software

• Lets you:

  • Record audio

  • Edit sound

  • Mix music

• Used like a mini music studio

📌 Printer Basics (Important Terms)

🧾 Image Quality (DPI)

• DPI = dots per inch

• More DPI = better print quality

  • 300 DPI → normal documents

  • 1200+ DPI → photos / high quality prints

⚡ Speed (PPM)

• PPM = pages per minute

• Color printing is usually slower than black & white

• “Fast” speeds are often in draft mode (low quality)

🔄 Duplexing

• Prints on both sides of paper automatically

• Saves paper (used for books, manuals, magazines)

💸 Materials

• Ink, toner, and paper can be expensive over time

🖨 Types of Printers

📌 Dot Matrix (old)

• Uses pins hitting ink ribbon

• Low quality

• Used for carbon copies/forms

🖌 Inkjet Printer

• Sprays ink onto paper

• Uses CMYK colors

  • Cyan, Magenta, Yellow, Black

• Good for home use

• Ink cartridges can be expensive

⚡ Laser Printer

• Uses laser + toner powder

• Very fast and sharp text

• Great for businesses

• Can be black-only or color

📠 Multifunction Printer

• All-in-one:

  • Print

  • Copy

  • Scan

  • Fax

• Popular in homes and small offices

🎨 Dye-Sublimation (Dye-Sub)

• Uses heated dye

• Produces high-quality photos

• Used for ID cards and professional images

🔥 Thermal Printer

• Uses heat on special paper

• No ink needed

• Used for:

  • Receipts

  • Labels

🧊 3D Printer

• Creates 3D objects layer by layer

• Uses plastic or similar materials

• Used for:

  • Prototypes

  • Toys

  • Parts and tools

📽 Projectors

• Show computer images/video on a large screen or wall

• Used for audiences (classrooms, meetings, presentations)

💡 Key facts:

• Can connect to:

  • Computers

  • Networks

  • USB drives

• Can be used with interactive whiteboards

📳 Haptic Technology (VERY important term)

💡 What it is:

• Output that you can feel (vibration or motion)

📱 Examples:

• Smartphones → vibration for calls/messages

• Game controllers → rumble effects in games

• Flight simulators → realistic movement feedback

• Robots → operators feel resistance when controlling machines

🧠 Easy Summary

• Projector = shows visuals to a large audience

• Haptics = computer output you can feel

• Haptics = vibration, motion, or resistance