Lesson video

Hello, my name is Mrs. Jones, and I'm really pleased that you've decided to learn with me today.

In this lesson, we're going to look at the different types of secondary storage, so let's get started.

Welcome to today's lesson.

Today's lesson is called Secondary Storage from the unit, Computer Systems. And by the end of this lesson, you'll be able to compare the characteristics of different types of secondary storage.

There are three key words to today's lesson.

Solid state storage.

Solid state storage has no moving parts and stores data in electrical circuits using zeros and ones.

Optical storage, optical storage uses lasers to read and write data on a reflective surface.

Magnetic storage, magnetic storage is an older format.

Data is stored in series as polarised dots.

There are three sections to today's lesson.

The first is define a storage device and storage media.

Second is describe the different types of secondary storage, and third is compare characteristics of secondary storage.

So let's start with define a storage device and storage media.

Using a computer requires you to store files and programmes.

When a computer has no power, it needs to store these files and programmes to be accessed next time they are required.

Storage media is the physical material where data is stored and this includes the hard disc drive, HDD, solid state drive, SSD, USB flash drive, memory card, CD.

A storage device is the hardware that reads from and writes to the storage media, and these include a computer, a mobile phone, a camera.

Let's have a quick check.

Which of the following would be a storage device? Is it A, hard disc drive? B, computer, C, USB flash drive, or D, memory card.

Pause the video, goes back through the slides and consider your answer and then we'll check it.

Let's check your answer.

The answer is B, computer.

Well done if you got that correct.

Let's do an activity and you'll need your worksheet.

Complete the table to define a storage device and storage media, you have a table with storage device and storage media on the left.

You need to describe each of those and then provide examples of each two.

Pause the video, go back through the slides, use your worksheet and then we'll check your answers.

Let's check your answers, let's look at storage device.

The hardware that reads from and writes to the storage media.

Examples include computer, mobile phone, camera.

Storage media, the physical material where data is stored.

Examples include the hard disc drive, solid state drive, USB flash drive, memory card, CD.

Well done if you've got that correct.

Let's move on to the second part of today's lesson.

Describe the different types of secondary storage.

General purpose computers need to be able to store programmes and files so they can be accessed whenever a user requires them.

RAM only stores data and programmes when they are currently in use.

A computer needs to store them when they are not in use.

This is why secondary storage is required.

Secondary storage is non-volatile, meaning it keeps data stored permanently even when the computer is turned off.

It is used for long-term storage of files and programmes that you want to keep.

Secondary storage is robust and reliable and is much cheaper per gigabyte than main memory.

It has more capacity to store data and can be portable.

It stores all files, folders and programmes including the operating system.

Let's have a quick check.

Why is secondary storage required in a computer? Is it A, to temporarily hold data and instructions that the CPU's currently using? B, to permanently store the operating system applications and user files even when the power is off.

C, to act as the main processing unit, carrying out all calculations and instructions or D to permanently, store the BIOS and start up instructions.

Pause the video, go back through the slides, consider your answer and then we'll check it.

Let's check your answer, the answer was B.

To permanently store the operating system applications and user files even when the power is off.

Well done if you got that correct, secondary storage can be put into three categories.

Each type is different and suits different devices.

The three types you can see there are solid state, optical and magnetic.

Solid state storage, like solid state drives, SSD, memory cards and USB flash drives saves data using electricity with no moving parts.

Inside are chips with billions of tiny cells, these cells can either hold an electric charge or not.

A cell with an electric charge represents a one while a cell without an electric charge represents a zero.

Optical storage uses lasers to read and write data on discs like CDs, DVDs, and blue rays.

Data is burned onto the disc as tiny pits and lands.

A laser then shines onto the disc to see if the light bounces or scatters.

A sensor reads these differences to know whether it is a zero or a one.

Magnetic storage, like a hard disc drive, uses magnets to save data.

Inside are fast spinning discs.

A tiny arm with a read, write head moves over these discs.

This head uses tiny magnets to flip the direction of magnetic spots on the disc.

One direction means zero, the other means one.

When you want to read a file, the head checks which way these tiny magnets are pointing.

Aisha asks, "Why do some computers have an SSD and some have a HDD? Good question.

Different computers have different secondary storage.

The cost and speed of different components can affect which is chosen when a computer is built.

Using a solid state drive is more expensive than a hard disc drive, but it can be quicker to load files and programmes.

Aisha asks, can I increase the capacity of my HDD to make it run faster? Another good question.

Increasing the capacity of the same type of trove does not make the faster, upgrading from a HDD to a SSD will improve speed.

The speed is determined by the drive type, SSD versus HDD, not how much it can hold.

Let's do an activity and you'll need your worksheet.

Describe why a computer needs secondary storage.

Pause the video, go back through the slides, use your worksheet and then we'll check your answers.

Let's check your answer.

General purpose computers need to be able to store programmes and files to be used whenever a user requires them.

RAM only stores data and programmes when they're currently in use.

A computer needs to store them when they're not in use.

Secondary storage is non-volatile, meaning it keeps data stored permanently, even when the computer is turned off.

Secondary storage is robust and reliable, cheaper per gigabyte than main memory, has more capacity to store data, is portable and is long-term storage for all files, folders and programmes including the operating system.

Well done if you've got that correct.

The next part of the activity is to complete the table to describe the types of secondary storage, you have a table with solid state storage, optical storage, and magnetic storage on the left.

You need to complete the table to describe what each is.

Pause the video, go back through your slides, use your worksheet and then we'll go through the answers.

Let's check your answers.

Solid state storage, inside are chips with billions of tiny cells, these cells can either hold an electric charge or not.

The cell within and without a charge represents a zero or a one.

Optical storage, data is burned onto the disc as tiny pits and lands.

A laser then shines onto the disc to see if the light bounces or scatters.

A sensor reads these differences to know if it's a zero or a one.

Magnetic storage, inside are fast spinning discs.

A tiny arm with a read write head moves over these discs.

This head uses tiny magnets to flip the direction of magnet spots on the disc.

One direction means zero, the other means one.

When you want to read a file, the head checks which way these tiny magnets are pointing.

Well done if you've got those correct.

Let's move on to the third part of today's lesson.

Compare characteristics of secondary storage.

Each type of secondary storage has advantages and disadvantages.

You can compare the different characteristics and you can look at capacity, which is the total amount of data it can hold.

Speed, how quickly data can be read from or written to it.

Portability, how easily it can be moved between different computers or locations.

Durability, its ability to withstand physical shock, impact or environmental factors without being damaged.

Reliability, the consistency and trustworthiness of it to store and retrieve data accurately without errors or failures over time and cost, the price of it or the cost per unit of storage, for example, per gigabyte.

Laura asks, "What are the advantages of using solid state storage?" Solid state storage has fast read and write speeds and won't break as easily.

It requires less power to run, is silent and reliable over many years, has a good storage capacity and external SSDs can move with you between devices.

Laura asks, what are the disadvantages of using solid state storage? Solid state storage is more expensive per gigabyte and usually has a lower capacity than magnetic storage due to the cost.

Let's have a quick check, which is a disadvantage of solid state storage.

Is it A, cost per gigabyte? B, fast read and write speeds.

C, moves with you between devices.

D, less power and silent.

Pause the video, consider your answer and then we'll check it.

Let's check your answer.

The answer was A, cost per gigabyte.

Well done if you got that correct.

Izzy asks, what are the advantages of using magnetic storage? Magnetic storage has a higher capacity to store data.

It has a moderate speed when running and a lower cost per gigabyte.

External HDDs are portable.

Internal HDDs can last a long time.

Easy asks, what are the disadvantages of using magnetic storage? Magnetic storage has moving parts and so can be damaged.

Internal HDDs are not portable.

Sophia asks, what are the advantages of using optical storage? Optical storage has a very low cost per gigabyte and can be easily moved from one device to another.

Sofia asks, "What are the disadvantages of using optical storage?" Optical storage has a lower capacity and is slower to access data.

It could be scratched and damaged if handled or stored incorrectly and can degrade over time.

Let's do an activity.

You'll need your worksheet and you need to complete the table to compare the advantages and disadvantages of each type of secondary storage.

You have the characteristics on the left, capacity, speed, portability, durability, reliability, and cost, and over the top you can see solid state, optical and magnetic.

Pause the video, go back through the slides, use your worksheet and then we'll check your answers.

Let's check your answers.

Capacity, solid state has good storage capacity, but lower than magnetic storage.

Optical has low capacity, magnetic has a high storage capacity.

Looking at speed, solid state has fast read write speeds.

Optical is slower to access data.

Magnetic has moderate speed.

Portability, solid state, external HDDs are portable, internal are not, optical, easily moved between devices and magnetic, external HDDs are portable, internal are not.

Durability, solid state is not easily broken as there's no moving parts.

Optical could be scratched and damaged if handled or stored incorrectly.

Magnetic, built using moving parts, so can be damaged.

Reliability, solid state requires less power to run, is silent and reliable over many years.

Optical can degrade over time.

Magnetic internal usually lasts a long time.

Cost, solid state is more expensive per gigabyte, optical, very low cost per gigabyte, and magnetic, lower per gigabyte.

Well done if you've got those correct.

In summary, secondary storage is non-volatile, long-term storage for all files, folders and programmes including the operating system.

Solid state storage uses non-volatile memory with no moving parts to store data electronically providing fast, durable and silent performance.

Magnetic storage uses magnetised areas on spinning platters to store data, offering high capacity at a lower cost, but with slower speeds and moving parts.

Optical storage uses lasers to read and write data as pits and lands on a spinning disc offering portability.

Well done for completing this lesson on secondary storage.