What Is an External Hard Drive ?

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1. The first hard drive ever – the 350 Disk Storage Unit was released in 1956 by IBM. It had a capacity of 3.75MB and was the size of a refrigerator.

2. When this behemoth became commercialized, it cost around $35’000. The price per storage unit was accordingly around $8500 per MB, which, compared to the average 5 cents per GB today, is 170 million times more expensive!

3. While the price difference makes it seem like a huge leap in scientific discovery, in reality, modern hard drives are very similar to the old one – they contain a set number of platters where the information is accessed by a read/write head.

4. But how far can we push storage today? Most tech-savvy people will tell you that HDDs trade data speeds for storage and SSDs trade storage space for speed. While this is overall true, the most spacious drive as of today is actually an SSD! The Samsung PM1633a is the most spacious hard drive as of May 2017 at 16TB.

Speaking of progress, many of you may have heard about Moore’s law – that every two years, computing power and storage space of systems roughly doubles. Unfortunately, Moore’s law is coming to a halt with HDDs, since the technology is reaching its physical limits. There are some methods to fixing this, but the rapid progress part has shifted to SSDs.

Hard disk platters are made out of expensive materials, such as platinum for its thermal properties, as well as ruthenium for its magnetic properties. Don’t try to pawn in piles of hard disk platters, though, since the expensive materials make up only a microscopic layer on top of what is usually either an aluminum or glass platter.

Contrary to what intuition and often times popular belief may tell you, hard drives are not airtight. They do, however, have filters so that there is no dust in the enclosure that could catastrophically affect your data.

Traditional hard disk drives have a capacity limit because of air resistance and power requirements limiting the amount of platters one drive can hold. Different aerodynamic processes make it extremely difficult to shove too many platters into one hard drive, while other such principles alongside power requirements make it very difficult for the platters to spin above 15k RPM.

Hard disks are also limited by the space that one bit takes on the disk platters since there is a minimum requirement for the read/write head to be able to read that information. A magnetically encrypted area of the platter too small may result in the data not being read.

While all this seems dreary for the future of HDDs, there are also innovative solutions to these problems, such as the Helioseal technology. The Ultrastar He12 helium hard drive by WD replaces the air inside the enclosure with helium, thus upping the limit for how many platters can be fit together in one case, resulting in 12TB of compact storage.

Speaking of compact storage, remember that first refrigerator-size hard drive from earlier? When compared to modern storage drives, the 350 Disk Storage Unit took up about 10 billion times more space per MB than an average HDD today.

The most data today circulates in social networks and video platforms. Facebook, for example, stored around 300PB (petabytes) in their data centers in 2013, meaning there’s way more today. YouTube, that is estimated to have 15 years of footage uploaded daily, stored around 500PB of data in 2015. It would take many lifetimes to go through all of those cat pictures and videos.

These numbers seem astronomical but more impressive is the fact that rough estimates, accordingly to Moore’s law, state that the amount of data stored by industries doubles every 1.2-2 years.

All of this information has to be stored in data centers – large facilities filled with rows upon rows of hard drives and servers. And while powering your PC doesn’t seem like much, a large data center could potentially require as much energy as a small city.

Today we have plenty of space for data centers, but putting them out of the way may actually provide some unexpected benefits. One example would be putting them underwater, like in Microsoft’s underwater data center experiment back in 2015, where a big capsule filled with servers was submerged in the ocean. This could simplify cooling, as well as speed up data transfer since half the world apparently lives next to a coastline.

16. In this list, all data amounts are shown in bytes, however, you may have sometimes noticed a data amount being measured in bits. Bits and bytes are not the same! A bit is either one or zero, while a byte is a combination of 8 bits, put into a more recognizable chain of signals for the computer. This means that 1TB (terabyte) of information, for example, could also be measured as 8Tb (terabits), but bits are mainly used in measuring bandwidth for interfaces.

While we’re all warmed up with math, we can also look at how binary stuff works. You’d imagine that a gigabyte would hold 1000 megabytes, but that’s not true. Since computers use the binary numbering system, any complete magnitude of data stored or transferred has to be an order of 2. This means that 1GB is not 1000MB, but rather 1024MB (or 2^10).

All this math may make you want to just remove all those megabytes and gigabits from your life. Well, this won’t be as easy as you’d think since file data doesn’t disappear when you delete them. The computer only assigns the space where those files are as reusable and while you can’t access them on your PC, they can be recovered with some very sophisticated data retrieval methods. So if you want to completely delete something, either use software for wiping drives or smash the hard drive.

The coolest way of deleting your data completely, though, is putting under a super-powerful magnet. Magnets can corrupt or completely destroy data on hard disk drives since the information is stored by magnetizing small portions of the disk platter surfaces. In one experiment

While destroying your data completely is not an easy task, protecting your hard drive with a password is easier than you might think. In fact, you can set up whatever password you want by accessing your BIOS. Before your operating system loads, your computer will let you access boot options by pressing either Esc or one of the Function buttons.

21. Conventional transistor electronics, including HDDs and SSDs, will reach their limit at some point in future because of quantum phenomena like superparamagnetism and quantum tunneling. In short, both phenomena can cause data memory cells to change their state randomly if they are too small, whether on an HDD platter or in SSD NAND gates.

HDDs may be completely replaced by SSDs in the future, but we will still see them hang around for a while because of innovative workarounds. We previously mentioned helium drives that would reduce mechanical forces on hard disks, but there is also more complex technologies like Shingled Magnetic Recording. SMR lets older information to be stored “underneath” newer one to make the storage system more compact.

What’s more interesting are entirely new ways to store data. One such method would be the so-called 5D storage that holds information within a glass plate. The main advantage of this is extreme durability – it is estimated that a tiny 5D glass platter could hold data for 13.8 billion years at average temperatures of 375 degrees Fahrenheit (190 degrees Celsius). While it is still difficult to access the data at reasonable speeds, the technology is still being developed, leaving much to be expected in the future.

There was a lot of talk about quantum computers a few years back but not much has been heard lately. But there’s nothing to worry about since the research in quantum computing continues, with success in both processing and first steps in storage systems.