Computer Hardware Notes

2.1 Buying the Correct Hardware

• When buying a new computer, consider how you will use it.

• Different computers have different specifications, advantages, and limitations based on their components.

• Gamers need different components than users who browse the internet and do word processing.

Computer Users

• Different types of computer users:

  • Home users

  • SOHO (small office or home office) users

  • Mobile users

  • Power users

  • Disabled users

• Understanding their needs helps in selecting appropriate components.

Home Users

• Use computers for:

  • Browsing the internet

  • Social networking

  • Sending emails

  • Word-processing tasks

  • Watching online and local videos

  • Listening to music

• Categorizing home users is harder now due to gaming and work-from-home trends.

• In 2017, there were $2.2$ billion gamers (roughly 30% of the world’s population).

• Almost 50% of Germans played video games; the average age of gamers in Germany was 35 years old.

• Many home users also work from home.

• Most home computers are used by multiple people.

• Flexibility is needed; a computer should handle basic tasks and gaming.

• Consider a desktop with a mid-range CPU and graphics card.

• A small printer is beneficial for most households.

• Single users who only do basic tasks can consider a mid-range notebook.

• Notebooks are more flexible and portable.

• Avoid budget notebooks (under R5 000) due to slow performance.

SOHO Users

• Small office or home office (SOHO) users use computers for:

  • Online research

  • Sending emails and business communication

  • Word-processing and spreadsheet applications

  • Note-taking

  • Printing documents

• Tasks don't require very powerful computers.

• Important factors:

  1. Mobility: Ability to carry the computer around.

  2. Battery life: Duration of use without a power source.

  3. Screen resolution: Amount of viewable information and display quality.

  4. Speed: Ensures good productivity.

• Ultrabooks are ideal: small, powerful notebooks with long battery life.

• Ultrabooks cost between R15 000 and R30 000.

• A mid-range notebook is a compromise.

• Stand-alone monitor, mouse, and keyboard improve productivity.

Mobile Users

• Travel frequently and need devices that are easy to use and transport.

• Should consider tablets, laptops, and smartphones.

• Requirements:

  • Mobility

  • Battery life

  • At least a 3G connection for internet access

Power Users

• Need computers with high processing capacity for:

  • Graphic design

  • Gaming

• Should buy a computer with:

  • Large storage space

  • Enough RAM

  • High-end CPU

• Power users often use computers similar to those used by gamers; some prefer ultrabooks if they travel a lot.

• Example: Stephen Hawking used computer technology to communicate and do research.

Disabled Users

• Modern technology enables people with disabilities to use computers and make daily lives easier.

• Computer type and requirements depend on the disability and the user's needs; research is important before buying.

Buying Recommendations

• Each user is unique and requires different hardware.

Productivity, Efficiency, Accuracy, and Accessibility Issues

• Computers improve productivity and efficiency by completing tasks quickly.

• Example: Car assembly can be completed within 8 hours by a computer, compared to months or years by a person.

• Computers ensure tasks are completed accurately via programming.

• Formulas and functions in computer programs reduce mistakes.

• Computers increase accessibility for people with disabilities.

2.2 Input Devices

• An input device enables a user to enter data into and interact with a computer.

• Examples: keyboard, mouse, scanners, and cameras.

Keyboard

• The most common and important input device for desktop computers.

• Consists of keys for commands or typing.

Advantages and Limitations of Keyboards

• Most modern computers come with a standard QWERTY keyboard.

Ergonomic Considerations

• Keyboard and mouse should be comfortable.

• Keyboard height should be just above lap level.

• Arms should be tilting downward when typing; use an adjustable keyboard tray.

• Keep wrists in a neutral (straight) position to prevent carpal tunnel syndrome and tendonitis.

• Adjust chair height so elbows are at a 90-degree angle or more.

• Keep shoulders relaxed and elbows at the side.

• Use a light touch on keys.

• Align body to the keyboard based on whether letters or numbers are used the most.

• Use keyboard shortcuts or macros for repetitive tasks.

• Buy an ergonomic keyboard if you suffer from hand, wrist, arm, or shoulder pains.

Mouse

• The second most common input device.

• A pointing device that moves the cursor and allows users to point, click, and select.

Advantages and Limitations of the Computer Mouse

• Very few computer applications do not require mouse.

Ergonomic Considerations

• Health issues can be caused by using a computer mouse: sore wrists, aching elbows, and shoulders.

• Mouse should fit comfortably in hand; use a symmetrical shaped mouse.

• Do not grip the mouse hard; hold it loosely.

• Rest hand over the mouse, index finger on the left button.

• Keep mouse at correct height and distance from body.

• Elbow bent and close to body.

• Use the entire forearm, not just the hand, to move the mouse.

• Keep wrist straight.

• Do not use a wrist rest.

• Use a soft touch to manipulate the mouse.

• Adjust mouse speed, double-click time, and cursor size.

Touch Screen

• Serves as both an input and an output device.

• Allows users to press buttons and select options directly on the screen.

• Common in smartphones.

Advantages and Limitations of Touch Screens

-Table 2.5 not included in the document

Touchpad

• A small square or rectangular input device on a laptop.

• Same function as a mouse

• Move finger across the pad to move the cursor.

• Two buttons: left (select) and right (menu).

• Includes a function to scroll up and down.

Advantages and Limitations of a Touchpad

• Not an efficient way to move the mouse cursor.

• Enables the use of notebooks without additional devices.

Digital Cameras

• Capture photographs and store them on a digital memory card instead of on film.

• Transfer images to computer, edit, print, or upload to the internet.

• Some can record video images with sound.

• Come with software to adjust contrast and sharpness, create and print photo albums.

• Examples: Digital Photo Professional and ZoomBrowser.

Advantages and Limitations of Digital Cameras

• Can preview and delete photos.

Resolution and Image Quality

• Resolution: the amount of detail a camera can capture; measured in megapixels.

• Higher resolution = clearer image.

• Lower resolution = blurry/pixelated image.

• Choice of camera resolution and image quality.

• Lower resolution:

  • Smaller file size

  • Take up less storage space.

  • Save time when transferring images.

• High resolution:

  • Better image quality

  • Allows the user to crop the image with little or no loss of quality

Webcams

• Digital camera connected directly to your computer.

• Allows streaming live videos.

• Consists of a lens, image sensor, and support electronics.

• Some include a microphone.

• Laptops and notebooks have a built-in webcam and microphone.

• Come with software to capture images and record videos, adjust camera sensitivity, and enable motion detection.

• Examples: Acer Crystal Eye Webcam and Logitech Webcam Software.

Advantages and Limitations of Webcams

• Make it possible to make and upload videos to YouTube and other social networks.

• Facilitate face-to-face conversations with people far away (video conferencing).

Microphones

• Input device to record sound, stored on your computer.

• Can record music, ambient sounds, and voice.

• Use with digital camera or webcam for videos, meetings, or chat programs (Skype).

Advantages and Limitations of Microphones

• Specialized microphones are needed for voice communication, even though notebooks and webcams have built-in microphones.

Voice Recognition

• Software that enables the computer to take verbal commands, translate, and interpret them.

• Converts audio to digital signals, compares signals to a database of words, phrases, and actions.

• Voice recognition is becoming more common.

• Apple’s Siri and Android’s Bixby work with voice recognition.

Voice Recognition for Marketing

• In 2017, Burger King ran an advertisement that triggered Google Home speakers to read the Whopper burger Wikipedia listing.

• Google prevented its speakers from responding by registering the sound clip and disabling the trigger.

• It was the first attempt by a company to purposefully hijack users’ devices for commercial gain.

Advantages and Limitations of Voice Recognition Software

• Table 2.10 not included in the document

Scanners

• An input device similar to a photocopy machine.

• Produces a digital copy (not a printed copy) that can be saved on your computer.

• Examples: flatbed scanner and mouse scanner.

• Mouse scanner: can use as a traditional computer mouse.

• Come packaged with optical character recognition (OCR) software, which converts the text on the scanned document to text that can be used in a word-processing application.

• The effectiveness of OCR depends on the quality of the scanned document.

Advantages and Limitations of Scanners

• Scanners are an important part of any office and can also be very useful for private use.

Wireless versus Cables Devices

• Wireless devices, such as keyboards and mice, are similar to the standard wired versions.

Wired Input Devices

• Connected via a wire to the computer, allowing information to travel between the two devices

Wireless Input Devices

• Wired keyboards and mice use a receiver that is plugged into the USB slot on a computer

• The input device then communicates with the computer, using a wireless transfer of data

• Both wireless and wired devices are similar, with only a few minor differences.

Risks Associated with Input Devices

• Input devices allow user interaction with the computer.

• Risks include:

  • Keystroke logging: Recording keystrokes to identify personal information (bank details, passwords) using malware.

  • Physical injury: Extensive use may lead to carpal tunnel syndrome or repetitive strain injury.

  • Pathogen transmission: Shared input devices can transmit germs.

  • Privacy issues: Hackers may access webcams and microphones to gain private images and conversations through malware.

Integration of Input Modes to Enhance Productivity and Efficiency

• Combining multiple input methods in a single device:

  • Mouse scanner

  • Smartphones: touch screen, microphone, camera (QR codes and facial recognition).

• Four-in-one printers: print/copy/fax/scan.

• Integrating barcode readers and OCR scanners with administration systems.

2.3 Storage Devices

• Storage devices store data.

• Internal: hard drive.

• External: portable hard drive or flash drive.

• Considerations when buying a new storage device:

  • Storage capacity

  • Storage speed

  • Volatility

  • Reliability and durability

• For internal hard drives, a storage speed of $7 200$ revolutions per minute (RPM) is a good starting point.

• For most people, $1$ Tb should be enough storage space.

Internal Hard Drives

• Store files for operating system, software, and personal information.

• Every modern computer comes equipped with an internal hard drive

Advantages and Limitations of Internal Hard Drives

• Modern hard drives have the potential to store up to $12$ terabytes ($12$ Tb) of data.

• This is enough space to store $3 000 000$ compressed songs (such as MP3s), or $17 000$ uncompressed CDs.

External Hard Drives

• Used as portable storage devices.

• Protected by a case and connected via USB.

Advantages and Limitations of External Hard Drives

• The small size and portability of external hard drives ensure that they can be quickly connected to different computers and are, therefore, ideal for transferring large amounts of data, or backing up data from your internal hard drive.

Why It Is Important to Back-Up Your Data

• Backing up data involves making a copy of important data on a separate storage device, kept at a different location.

• Traditionally, external hard drives, flash drives, CDs, and DVDs were used.

Solid-State Drives

• Storage device that does not use mechanical parts.

• Consists of interconnected flash memory chips made of silicon.

• Functions like a CPU with billions of small transistors.

Advantages and Limitations of Solid-State Drives

• Faster than normal hard drives.

• Lower storage capacity and higher cost per gigabyte.

• Use an SSD to improve the performance of certain programs and not as a primary storage device.

Flash Drives

• A small, portable storage device.

• Connects to computer via USB.

• Best way to transfer data between two computers.

• Ideal storage device for documents and photos.

Advantages and Limitations of Flash Drives

• Flash drives have a very high cost per gigabyte.

• Recommended to base your purchase on the amount of data that you want to transfer or store.

Optical Disc Drives

• Multi-purpose drives for reading data from optical discs (CDs, DVDs, and Blu-ray discs).

• Also used to record data.

Advantages and Limitations of Optical Disc Drives

• Gives the user an affordable and time-efficient way of producing multiple copies of a disc that contains information.

Capacity and Cost of the Most Common Storage Devices

• Provided basic look at the some of the most commonly used storage devices.

• Have discussed the advantages and limitations of each device, and have given some indication of which device will be suited for a specific task.

Cloud Storage

• Allows users to store information on the internet.

• Examples: Apple’s iCloud and Google’s Google Drive.

• Both provide free storage (5 Gb for iCloud and 15 Gb for Google Drive).

2.4 Processing Devices

• Devices that modify and change data before it is sent to the output device.

• Includes the CPU, GPU, and RAM.

Central Processing Unit

• One of the most important parts of any computer.

• Tasks:

  • Receiving and carrying out computer’s instructions

  • Allocating more complicated tasks to other chips that will better handle the task

• Functions using billions of microscopic transistors.

Evaluating a CPU

• Consider:

  • Gigahertz of the processor

  • Number of cores

Graphics Processing Unit

• Responsible for display functions.

• Makes calculations and follows instructions.

• Limited to calculations needed to render and display images on the screen.

Evaluating a GPU

• Deciding which GPU is best suited to your needs, ask yourself the question: “What am I going to use my computer for?”

• Most modern computers come equipped with a fairly powerful onboard GPU that is more than capable of performing the actions needed by the average computer user.

• manufacturers that have a variety of products with different specifications.

• To find the correct product for your needs, you have to look at the manufacturer’s model numbers and benchmarks.

• Looking at the model number will provide you with an indication of which generation the card is, while the benchmarks will show you how powerful it is.

Random Access Memory

• A chip responsible for temporarily storing data.

• Enables the computer to work with a vast amount of information at the same time.

• Storage data that is currently being used, and loading the data that they may want to use next.

Evaluating RAM

• RAM needs to me much faster than any other storage device.

• Very important that your computer is equipped with enough memory to allow the GPU and CPU to operate at their full potential.

• Determining how much RAM is needed will depend on the following two main factors:

  1. Which operating system are you using?

  2. What are you planning to do with your computer?

2.5 Output and Communication Devices

• Look at some of the most common devices that are used to present the processed data to the user, or to other computers and networks.

Output Devices

• Any device that takes the data that has been stored on a computer and makes it available to the user.

• Examples:

  • Computer screen

  • Printer

  • Speakers

Computer Screen

• Most important output device.

• Enables visual interaction with data and programs.

Evaluating a Computer Screen

• Pixels: 1 920 pixels across the width of the monitor and 1 080 pixels across the height of the monitor.

• Screen size: Measured diagonally in inches; consider desk size.

• Refresh rate: Amount of time it takes for the screen to be updated (60 Hz is sufficient).

Virtual Reality

• A type of output device that uses a specially designed headset to fully immerse the user in a high-quality 3D virtual world using both sight and sound.

• Sets virtual reality apart from other 3D viewing devices is that it is not limited to just normal 3D images.

Speakers

• Play back sound; enable listening to music, Skype, or movies.

Evaluating Computer Speakers

• Most computers have their own built-in speakers, which are fine for hearing the normal computer sounds.

• Speakers with or without a subwoofer

• Specifications and sound quality

• Input

• Control

• Appearance

• Price

Printers

• Device that transfers text and graphic output data from your computer to a piece of paper.

• Select a printer based on what you will be using the printer for.

• Speed

• Paper type and size

• Printer resolution

• Costs to print a page

• Memory

• Wireless capabilities

• Ink cartridges

Communication Devices

• Connect a computer to other computers in a network.

• Examples: network/Wi-Fi card and router.

2.6 Troubleshooting Hardware Devices

• Most common issues that you might encounter, as well as how to resolve them.

Erratic Mouse Movement

• The mouse is dirty

• Bad surface

• Wireless mouse

Scanning

• A skew or cut-off scanned document

• Poor image quality

• Connection errors

Disk Errors (Defragging)

• Hard drives are prone to wear and tear, which can lead to a variety of problems, such as disk errors caused by disk fragmentation.

• Therefore, it is very important to regularly check the condition of the hard drives to make sure that they do not fail.

Printing Problems

• Printing takes too long

• Paper jams

• Bad printing quality

• Printer does not print

Lack of Free Space on Storage Medium

• This issue can be resolved by deleting some of the files that you no longer need.

• To determine how many files you should remove, look at the amount of free disk space that is currently available.