Digital Storage and Cloud Computing – SS1 Digital Technologies Lesson Note (Second Term)

Digital storage is the technology that holds your files, photos and apps even when the power is turned off. It can be local, such as a hard disk, SSD, flash drive or memory card, or in the cloud, where files are kept on servers and reached over the internet.

Behavioural objectives

By the end of the lesson, students should be able to:

1. define digital storage and name the units used to measure it;
2. list four local storage devices and describe each one;
3. explain cloud computing and name popular cloud services;
4. state the advantages and disadvantages of the cloud;
5. explain what a backup is and describe the 3-2-1 rule.

What is digital storage?

Digital storage is the technology that holds your files, photos and apps even when the power is turned off.

• Purpose: it keeps data so you can use it again tomorrow, next week or next year.
• Without it: a computer would “forget” everything each time it restarted.
• Desk idea: RAM is the top of the desk where you work right now, and storage is the drawer where you put things away.

What is the difference between RAM and storage?

RAM is the temporary memory that holds the work a computer is doing at that moment.

Storage is the long-term space that keeps files until you delete them.

How is digital storage measured?

Digital storage is measured in bytes, and one byte is made of 8 bits.

• Bit: the smallest unit of data, a single 0 or 1.
• Byte (B): 8 bits, enough to store one letter or number.

• Order: KB is smaller than MB, MB is smaller than GB, and GB is smaller than TB.

What is local storage?

Local storage is any storage device that you can hold in your hand or that is inside your machine.

What are the types of local storage?

There are four main types of local storage: hard disk drive, solid state drive, flash drive and memory card.

1. Hard Disk Drive (HDD): traditional storage found inside many desktop computers, with spinning disks inside.
2. Solid State Drive (SSD): the modern version, with no moving parts, so it is faster and harder to break than an HDD.
3. Flash drive (USB stick): a small, portable stick you carry in your pocket to move files between computers.
4. Memory card (SD card): a tiny chip used in phones and cameras to expand their memory.

What is the difference between an HDD and an SSD?

An HDD stores data on spinning disks, so it has moving parts.

An SSD stores data on memory chips, so it has no moving parts.

What is cloud computing?

Cloud computing is the use of servers on the internet to store files and run services instead of using only your own device.

• Not in the sky: the “cloud” is a collection of powerful computers, called servers, kept in large data centres.
• Owners: companies such as Google, Microsoft and Amazon run these data centres.
• Problem it solves: if you leave your flash drive at home, you cannot reach your files, but cloud files can be opened from any device.

How does saving to the cloud work?

1. You log in to a cloud service on your phone or computer.
2. You upload a file over the internet.
3. The file is stored on a server in a data centre.
4. Later, you log in on any device with internet and download or open the file.

What are examples of popular cloud services?

Four popular cloud services are Google Drive, iCloud, OneDrive and Dropbox.

• Google Drive: great for documents and school work.
• iCloud: used by Apple users to save photos and phone backups.
• OneDrive: Microsoft’s storage system.
• Dropbox: a simple way to share large files with friends.

What are the advantages of the cloud?

The main advantages of the cloud are access everywhere, safety from physical damage, easy sharing and automatic backups.

1. Access everywhere: you can start an essay on a school computer and finish it on your phone on the bus.
2. Safety from physical damage: if water spoils your laptop, your files are still safe in the cloud.
3. Easy sharing: you send a “link” to a friend instead of copying a large video to a flash drive.
4. Automatic backups: many cloud services can save your photos as soon as you take them.

What are the disadvantages of the cloud?

The main disadvantage of the cloud is that you need an internet connection to reach your files.

• Internet needed: no connection means no access to files kept only online.
• Data use: uploading and downloading large files uses mobile data.
• Account security: a weak password can let someone else open your files.

Teacher’s note: Remind students that the main downside of the cloud is that you need an internet connection to reach your files.

What is the difference between local storage and cloud storage?

Local storage keeps files on a device you own, while cloud storage keeps files on servers reached through the internet.

What is data backup?

A backup is a duplicate copy of your most important data stored in a different location.

• Why it matters: if your phone is stolen or your computer crashes, a backup lets you recover your work.
• Without a backup: three weeks of project work can be lost for good.

What is the 3-2-1 rule of backup?

The 3-2-1 rule says to keep 3 copies of your data, on 2 types of storage, with 1 copy off-site.

• 3 copies: the original and two backups.
• 2 types of storage: for example, your hard drive and a flash drive.
• 1 copy off-site: stored away from your device, such as in the cloud.

How can you keep your files safe?

• Back up often: do not wait for a “warning”. Back up your files once a week.
• Use passwords: protect your cloud accounts.
• Test your backups: check now and then that the files still open.

Evaluation

1. What is the main difference between an HDD and an SSD?
2. Explain “cloud computing” to someone who has never heard of it.
3. List three popular cloud storage providers.
4. Why is it risky to keep your only copy of a project on a single USB flash drive?

Assignment

Write a short guide on digital storage for a classmate. It must include:

1. the four local storage devices, with one sentence about each;
2. the 3-2-1 rule of backup, explained in your own words;
3. two advantages of storing files in the cloud instead of on a flash drive.