How Do Flash Storage Servers Work?

Flash Storage Servers make use of flash memory to store data for extended periods of time. Flash memory gets its name because information can be released and stored in a 'flash’, the name is also partly inspired by a camera flash.

Flash Storage Servers

A server is a computer that receives, processes and sends digital information to other computers connected to it via a network, such as the internet. When you use the internet, you are first connected to a giant server that processes your information and replies back to you.

Think of a server as a giant pump that is constantly engaged in transferring digital data through a network of computers. There are several types of servers. For example:

  1. A web server facilitates functioning of applications and shows internet pages.
  2. An identity server is used for logging into websites.

As the name suggests, a storage server, also known as a file server is used for storing and accessing data. It is usually less powerful than some of the other types of servers. However, it has a massive advantage over them – it can store very large amounts of data.

There are many ways to store data in a combination of zeros and ones. (Hence the term 'digital’). Information can be stored on floppy disks, CDs, hard drives or in flash memory sticks. A flash storage server stores data using flash memory.

Let’s learn a bit more about flash memory:

Flash is a very popular way to store information as it is a non-volatile form of memory. It does not require continuous power supply to store the data.

The RAM (Random Access Memory) of your computer or mobile is a volatile form of memory. This type of memory is very powerful (fast) but it can only be accessed when there is continuous power supply. Once the power is turned off, the memory shuts down.

This is precisely why your mobile 'turns off’ when the battery gets drained. However, as you know, all your saved information (photos, videos etc.) remains stored in the flash memory card. It does not get erased due to the absence of power. The data stored in it can be accessed after many days, weeks, months and even years. This type of storage is very convenient and useful. No wonder flash memory is so popular and ubiquitous.

Flash Memory Fun Fact: Dr. Fujio Masuoka invented Flash memory in 1980s while he was employed at Toshiba. This forever changed the way data was stored.

So How Does Flash Memory Work?

Flash is a kind of EEPROM, which stands for electronically erasable programmable read only memory. There is a slight difference between flash and conventional EEPROM though. Flash memory erases whole blocks of data (image, file, video etc.) while EEPROM has the ability to erase single bits of data.

One of the best aspects of Flash memory is that it does not involve any type of moving mechanical parts. This greatly reduces power consumption. In contrast, a storage device like a CD has to move (spin) for the information to be accessed. This requires lots of energy and the friction (caused by spinning) increases wear and tear, thus limiting the life span of the stored data.

Flash memory utilizes a special type of transistor that remains 'ON’ or 'OFF’ even when the power supply is turned off. A regular transistor has 3 kinds of controlling wires – the source, the drain and the gate. Just as water flows through a pipe, electricity flows through a transistor.

Just like a water pipe, a transistor has a tap (source) and a drain. In between the two, there is a gate. When the gate is closed, electricity cannot flow through the transistor. This means that it is switched off and stores a ZERO. When the gate is open, the transistor, current flows and the transistor stores a value of ONE. However, as soon the current is switched off, the transistor switches off too, thus forgetting everything everything.

A flash transistor has two gates instead of one – floating gate and control gate. When the floating gate is opened, some of the current leaks through and stays between the two gates. This means that the transistor has stored a number one. Even when the current is switched off, the electricity(electrons) between the two gates stays the same way. Thus, the capacitor does not 'forget’.

The current that is trapped between the two gates can be drained by applying a negative charge and repelling the electrons back to where they came from – this erases the stored information.

How long does flash memory last?

The floating gates begin to react slowly after being opened and shut several thousand times. It is thought that flash memory can be rewritten 10,000 times. However, newer technology has raised this to a whopping 100,000 rewrites.

Actually, even 10,000 is a very good number for portable flash storage drives, memory cards etc. Some high end flash storage devices have a rewriting capacity of one million per block!

What are the main advantages of a flash storage server over other forms of storage?

  1. Fast accessing of data: Data contained within flash storage can be accessed one hundred times faster than in a hard disk drive (HDD). This gap is increasing with each passing year. High speed access to information greatly improves performance and efficiency on networks with multiple computers.
  2. Durable: Flash has no moving parts. It is fully electronic. No moving parts means no friction and a longer lifespan. A DVD on the other hand becomes redundant if it gets scratched while spinning.
  3. Decreased power consumption: HDDs (hard disk drives) involve constantly spinning discs and hence they require large amounts of electricity. The motion also generates quite a bit of heat. This increases the air-conditioning cost in large server rooms.

Many people avoid flash storage servers because they are slightly pricey. However, it is important to note that flash storage requires very little electricity and also does not heat up quickly. Thus, it saves a lot of money in the long run.