Basic 9 · Computing · Components of Computers
Output Devices and Storage Systems
In this topic you will discuss the uses of modern output devices such as wearable displays, e-paper and e-books, and describe storage systems and how they work.
By the end of these notes you should be able to:
- Describe wearable displays, e-paper and e-readers
- Identify storage systems and their uses
- Compare storage options
What you already know
- Input and output devices
Copy everything that has a blue line on its left into your notebook. The other parts are for reading.
Lesson 1
- Strand
- Introduction To Computing
- Sub-strand
- Components of Computers
- Indicator
- B9.1.1.1.3 – Discuss the uses of Output devices such as Wearable Displays, E-Paper, E-Books, Kindle
Introduction
A book that weighs less than a bottle of water can hold thousands of titles. Output devices are changing the way we read and see information.
1. Modern Output Devices
| Device | What it does | Example |
|---|---|---|
| wearable display | shows information on the body | smartwatch, smart glasses |
| virtual reality headset | shows an immersive 3D world | VR headset |
| e-paper | a display that looks like ink on paper | e-reader screens |
| e-book reader | shows digital books | Amazon Kindle |
| digital signage | shows public messages | screens at airports |
2. Wearable Displays
Wearables are computers worn on the body. A smartwatch shows messages, the time and health data such as heart rate. Smart glasses can show directions or instructions in the wearer's field of view. Virtual reality headsets block out the outside world and create a simulated environment, which can be used for training doctors, pilots and engineers. Augmented reality adds digital information to a view of the real world. These devices provide information without you having to look down at a phone.
3. E-Paper
Electronic paper, or e-paper, imitates ink on paper. Unlike a phone screen, it does not shine light at you. It reflects light from the room, as a real page does. It uses tiny capsules with black and white particles, which move when an electrical charge is applied. Once the image is set, it uses almost no power. That is why e-readers can last for weeks on a single charge. The screen is also easy to read in bright sunlight, which is useful in Ghana's climate.
4. E-Books and E-Readers
| Feature | Printed book | E-book |
|---|---|---|
| weight | can be heavy | one device holds many books |
| power | none needed | needs charging |
| cost | printing and transport | less after buying the device |
| sharing | easy to lend | depends on licences |
| storage | needs shelves | digital memory |
| search | index only | quick word search |
A Kindle is an e-reader made by Amazon. Others include Kobo. E-books can also be read on phones, tablets and computers. Digital libraries offer free books, some of them through projects like Worldreader, which has provided e-readers and digital books to African schools, including those in Ghana. E-books can help with learning where printed books are in short supply.
5. Limits
New output devices may be expensive and fragile. They need charging and may need an internet connection for some functions. Screens can tire the eyes if used for long periods. Keep health in mind, and take regular breaks. Choose a device to suit the task and do not buy technology just because it is new.
New words
- wearable
- A device worn on the body.
- e-paper
- A display that imitates ink on paper.
- e-reader
- A device for reading digital books.
- virtual reality
- A simulated world shown through a headset.
Summary
- Modern output devices include wearables, VR and e-paper.
- E-paper reflects light and uses little power.
- E-readers give access to many books.
Class activity: Compare Devices
- Compare a phone screen and a page of a book.
- Discuss their strengths and limits.
- Share your conclusions.
You need: E-reader tablet, Printed wearable-display photograph, Printed e-paper comparison card
Exercises
Answer in your exercise book first, then check your answers.
1. A Kindle is an…
- A. e-reader
- B. input scanner
- C. router
- D. projector
Show answer
Answer: e-readerAmazon.2. E-paper uses little power because…
- A. it needs power only to change the image
- B. it has no screen
- C. it runs on water
- D. it is printed
Show answer
Answer: it needs power only to change the imageDesign.3. A smartwatch is a wearable device.
- A. True
- B. False
Show answer
Answer: TrueWorn.4. A simulated world shown through a headset is ______ reality.
Show answer
Answer: virtualVR.5. Give two advantages of e-books.
Show answer
Answer: One device stores many books, and text can be searched quickly.Any two.6. Why are e-readers useful in bright sunlight?
Show answer
Answer: E-paper reflects light from the surroundings like paper.Technology.
Lesson 2
- Strand
- Introduction To Computing
- Sub-strand
- Components of Computers
- Indicator
- B9.1.1.1.4 – Describe Storage Systems
Introduction
Every photo, song and document must be kept somewhere. Storage systems preserve our data when the power goes off.
1. Memory and Storage
Primary memory, such as RAM, holds data the computer is currently using, and it loses its contents when the power is turned off. Secondary storage keeps data permanently. This is what we mean when we talk about storage systems. Storage is measured in bytes. One kilobyte (KB) is about 1,000 bytes, and 1 megabyte (MB) is about 1,000 KB. A gigabyte (GB) is about 1,000 MB, and a terabyte (TB) is about 1,000 GB.
2. Types of Storage
| Type | How it stores data | Examples | Typical use |
|---|---|---|---|
| magnetic | magnetised surface | hard disk drive, tape | computers, backups |
| optical | laser on a disc | CD, DVD, Blu-ray | films, software |
| solid-state | flash memory chips | SSD, USB drive, memory card | phones, laptops |
| cloud | remote servers over the internet | Google Drive, OneDrive | sharing, backup |
| network | a server on a network | network attached storage | offices |
3. Comparing Storage
| Feature | HDD | SSD | Flash drive | Cloud |
|---|---|---|---|---|
| speed | moderate | very fast | moderate | depends on the internet |
| capacity | very large | large | small to medium | flexible |
| cost per GB | low | higher | moderate | monthly fee beyond a free limit |
| durability | moving parts | no moving parts | small and portable | not lost with your device |
4. Choosing a Storage System
Your choice depends on capacity, speed, cost, portability and safety. A school might keep records on a server and a backup offsite. A photographer needs large external drives. A learner might use a flash drive and free cloud storage. An important rule for backups is 3-2-1: keep three copies of your data, on two kinds of media, with one copy in a separate place. If a laptop is stolen, a backup means that the work is not lost.
5. Protecting Stored Data
Flash drives can spread viruses, so scan them before opening files. Keep magnetic drives away from strong magnets, and avoid dropping them. Eject drives safely before pulling them out. Cloud data needs a strong password and two-step verification. Deleting a file does not always remove it for good, so take care when selling old devices. Data centres also use a great deal of energy, so delete files that you no longer need.
New words
- secondary storage
- Long-term data storage.
- flash memory
- Storage in electronic chips.
- cloud storage
- Saving data on remote servers.
- terabyte
- About 1,000 gigabytes.
Summary
- Storage keeps data when the power is off.
- Types include magnetic, optical, solid-state and cloud.
- Choose by capacity, speed, cost and safety, and keep backups.
Class activity: Choose the Storage
- Read scenarios such as a school office or a photographer.
- Choose the best storage for each one.
- Justify your choices.
You need: USB flash drive, Hard disk drive, Memory card
Exercises
Answer in your exercise book first, then check your answers.
1. Which is a solid-state device?
- A. flash drive
- B. DVD
- C. floppy disk
- D. cassette
Show answer
Answer: flash driveChips.2. How many GB is 1 TB, approximately?
- A. 1,000
- B. 10
- C. 100
- D. 1,000,000
Show answer
Answer: 1,000Units.3. RAM loses data when the power goes off.
- A. True
- B. False
Show answer
Answer: TrueVolatile.4. Saving files on remote servers is ______ storage.
Show answer
Answer: cloudInternet.5. Compare HDD and SSD.
Show answer
Answer: SSDs are faster and have no moving parts, while HDDs are cheaper per GB.Comparison.6. Explain the 3-2-1 backup rule.
Show answer
Answer: Keep three copies on two types of media, with one stored elsewhere.Backup.
Homework
- Back up one important file in two different places.