Find out how SSD drives work

Today, when you buy a new computer or upgrade an old computer, you'll want to buy a solid-state drive (SSD) instead of a traditional hard drive. Indeed, switching from HDD to SSD is one of the best computer performance upgrades. So why and what makes SSDs a breakthrough technology?

This article will explain exactly what SSDs are, how they work, why SSDs are useful and major drawbacks when using this type of hard drive. If you want to seek advice when buying an SSD, read the article How to choose the SSD for your needs and the best SSD for Windows 2018 computers.

Learn about computers and memory

To understand how SSDs work and why they are so useful, we must first understand how computer memory works. Computer memory architecture is divided into three parts:

1. Cache memory

2. Memory

3. Data drives

Each of these parts performs an important function, deciding how they operate.

Cache is the internal memory. When running, the computer uses cache to conduct data calculations. The path to cache is the shortest, making data access almost instantaneous. However, the cache is very small, so its data is constantly overwritten.

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Memory may be known to you as RAM, this is where computers store data related to programs and active processes. Access to RAM is slower than cache access but not significant.

Data drives are where everything else is stored for a long time. This is the place to store all programs, configuration files, documents, music files, movies and everything else. When you want to access a file or run a program, the computer needs to download it from the data drive and into RAM.

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It is important to know that the speed between these three memory is different. While cache and RAM operate at nanoseconds, a traditional hard drive operates at milliseconds.

In essence, the data drive is the bottleneck, no matter how fast everything else is, the computer can only download and store data quickly when the data drive can handle it.

So this is why people invented an SSD. Although the HDD is slower than cache and RAM, SSDs are much faster. This greatly reduces the amount of time it takes to load programs and processes and you will see computers much faster.

1. Learn the types of memory in the market

How the SSD works

SSDs have functions like HDD hard drives, which store data and files for long-term use. The difference between them is that the SSD uses a type of memory called flash memory, similar to RAM but not like RAM in that it deletes all the data when the computer is turned off, the data on the SSD is still there even when it loses power.

If you remove a typical HDD, you'll see a stack of magnetic disks with the reader, like a reader in an old music player. Before the reader can read or write data, these discs must rotate in the right position.

On the other hand, an SSD uses a sheet of electrical cells to quickly send and receive data. These sheets are divided into sections called 'pages' and where data is stored. These pages are grouped together to form 'blocks'. SSDs are called solid-state drives because they don't have moving parts.

1. Differences between SSD and HDD hard drives

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SSDs can only write to a blank page in a block. In the HDD, data can be recorded anywhere on the disk at any time. This means data will be overwritten more easily. SSDs cannot directly overwrite data on individual pages, they only write data to blank pages in a block.

So, how does SSD handle data deletion? When pages in a block are marked as unused, the SSD determines the data of the entire block into memory, then deletes the entire block and redefines the data from the memory back to the block while leaving blank unused pages. Note, deleting a block does not mean that the data completely disappears.

Does this mean that SSD becomes slower over time?

When there's a new SSD, it's loaded completely with blocks filled with blank pages. When writing new data to SSD, data will be immediately written to those blank pages at a fast speed. However, as more and more data is recorded, blank pages run out and leave unused pages scattered throughout the blocks.

Because SSDs do not directly overwrite a single page, every time you want to write new data, the SSD needs:

1. Find a block with enough pages marked "not in use"

2. Recording the pages in that block is still necessary

3. Reset all pages in that block to blank

4. Rewrite the necessary pages to the newly reset block

5. Fill in the remaining pages with new data

So in essence, when you use all the blank pages on the new SSD, your drive will have to perform this process whenever you want to write new data. This is how flash memory works. However, it is still faster than a traditional HDD and the speed achieved when using an SSD is worth buying it instead of the HDD.

Disadvantages of SSDs

Now that we know how SSD drives work, it is also understandable that its biggest drawback is that flash memory can only maintain a finite amount of write before it "dies."

There are a lot of scientists who explain why this phenomenon happened, when using SSD in general, the charge in each of its data cells must be reset periodically. However, the resistance of each cell will increase slightly each time to reset, increasing the voltage needed to write to the cell. Finally, the required voltage becomes too high that specific cells cannot write data.

1. Signs that you should replace the SSD

Therefore, the SSD data cells have a finite amount of writes. However, that doesn't mean its life is short. If you are worried, please refer to the article How to increase the life and performance for SSD.

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Although SSD has some advantages, you should also consider the following before investing in an SSD:

1. In the consumer segment, SSDs are often more expensive than HDD hard drives.
2. Due to the SSD's unique file system structure, extracting data can be an extremely difficult and lengthy process.
3. Because the data recovery process is very difficult and takes a long time, it can be quite expensive.
4. Memory chips in an SSD have a limited number of write cycles, which can lead to data loss that cannot be recovered.
5. If the controller chip, cache or one of NAND memory chips is physically damaged, your data may be completely inaccessible.

If you are willing to take risks, you can enjoy all the benefits of SSD. However, you will have to make sure that you are prepared for the worst by regularly backing up your files.

SSD performance

High performance of SSD is the most important reason to use them for businesses. 95% of respondents said performance is the main criterion for buying SSDs. Only 31% of respondents believe that reliability is a factor. The number of SSDs that need to be destroyed or destroyed is expected to increase significantly in the next few years, when the proportion of businesses using SSD increases. Survey responses show that a total of 70% of companies have used SSDs since 2011 or 2012.

When a company replaces some SSDs, there will be a real need to ensure business continuity and prevent loss of confidential data. Recovering data from SSDs and canceling secure data are important needs to be addressed. However, most companies do not have the proper method to recover data from faulty drives or safely handle SSDs. Data recovery can be very difficult because proprietary encryption technologies are used.

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Handling SSDs

SSD is also not perfect

We can easily see that SSD is very safe because the data is stored on flash memory chip instead of magnetic tape or disk. Therefore, data loss is often due to unavoidable mechanical problems or hardware failure. SSD is not perfect. The survey revealed that more than half of the participants (51%) had to replace the faulty SSDs one or more times.

Delete - not always safe

Jim Reinert, senior director of Kroll Ontrack, said: 'Our survey shows the destruction of a series of ongoing SSDs.' 'Assuming the average life cycle of a business drive is about three years, many companies will face the question of how they can safely dispose of their old SSDs without causing Dangerous for sensitive company data. Many companies are facing the risk that some sensitive data remains on the drive may fall into the wrong hands'.

The importance of safe data deletion

To ensure that there are no compliance with security rules, deleting secure data is essential. However, the usual methods may not always remove all data on the SSD and flash drive. Due to the special technical structure of the data on the SSD, each operation records data to another physical location. Therefore, it is possible that even after multiple recordings, traces of the original data remain in a specific memory section. Therefore, these methods are not suitable for companies with high data security needs.

The Kroll Ontrack survey shows that there is no standard for deleting an SSD. 40% of surveyed companies choose physical destruction methods for SSDs (usually by a shredder). 31% use software to delete data. About 22% use encryption methods to remove hardware or software keys before replacing SSDs to make data unreadable. In addition, nearly 20% of respondents did not make a decision and there was no other data cancellation method.

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How to protect data on SSD without risk

So far, destroying SSDs by physical means is the only really safe method to erase SSD data.

In addition, there are several other options as follows:

1) Do not use self-Encrypting Drive (SED) drives: This type of encryption is very safe, but you will lose all data in case an error occurs. With SED, encryption keys are the responsibility of hardware manufacturers. This means that in the event of an error, professional data recovery companies cannot access the data either. Therefore, the use of this technology is not widely recommended.

2) Override SSD with professional erase software when SSD no longer works: Many times overwriting with specialized software is the first step. Professional software for deleting data by overwriting data many times is the best way to ensure no data can be recovered.

3) Make the remaining data encrypted and inaccessible: Unlike traditional hard drives, deleting SSDs cannot guarantee that there is no data left in separate blocks. odd. The best way to combat this is to delete the encryption keys or change the password when SSD is inactive or at least frequent. Deleting the decryption key will make any remaining data permanently unreachable.

Hopefully after this lesson you have a little more understanding of how SSDs work.

See more:

1. 5 mistakes easily 'kill' the SSD
2. 11 things to do when using SSD hard drive on Windows 10
3. How to install and use SSDs for laptops