Hard Drives: Explained

What is a hard drive?

Think of your computer as an office. The man at the desk is the CPU, and he’s doing all the work, all the thinking. The desk he sits at is the RAM, and the bigger the desk, the more things he can work on at one time (that’s why more RAM is usually better for most people). The file cabinet, where he stores all the things he’s done and all the things he’s not working on at the moment, is the hard disk drive, or HDD.

The insides of a mechanical drive

The insides of a mechanical drive

The basic principles of hard drive technology haven’t changed much in the past 50 years: a smooth platter coated with magnetic particles spins at high speeds, and an armature with a read/write head attached writes and erases data. The big changes have been in size and speed: today’s most common drives spin at 7,200 RPM or 5,400 RPM, faster than your car at redline; and the read/write head moves at speeds faster than your eye can see. While the first hard drives stored 5 MB of data, most common drives these days store 100,000x that much – 500 GB or more, and as much as 8,000 GB on some new models!

A hard drive can only last so long, what with all those moving, precision, highly sensitive parts. A typical consumer model lasts about five to seven years, or about 20,000 total power-on hours. There are some high-quality, expensive, desktop-sized (3.5″ width) drives that are designed to stand up to longer, continuous use, but these are rare to see outside of certain business applications.

These drives are also sensitive to bumps, drops, and falls. If your computer is dropped while it’s on, chances are the hard drive is permanently damaged. Hard drive failure usually has a noticeable onset, with the computer gradually getting slower as it has difficulty seeking data. You may notice harsh or rhythmic clicking noises, or the computer may fail to boot or show a message like “operating system not found”. You may also see a warning message issued by the computer at startup or within Windows. If you notice warning signs like this, you should get the hard drive replaced immediately! If you wait too long, you run the risk of losing your data permanently.


Options for everybody

There are different types of hard drives, with different advantages and disadvantages. In this section, we’ll attempt to explain the different technologies and how they work, so that you can make an informed decision when it comes time to replace your existing drive.

A traditional mechanical drive

A traditional mechanical drive

Mechanical Hard Drives (HDDs) use traditional spinning-platter technology and provide mass storage at low prices. You’ll usually pay $0.05-$0.06 per gigabyte of storage. The advantage of a mechanical drive is that it is crazy cheap, even for large sizes.

The list of disadvantages is rather long, however: having motors, they can be hard on battery life. As mentioned before, they are extremely sensitive to bumps and drops. And they’re comparatively slow. Even a 7,200 RPM drive can only move so fast, and some modern technology has outpaced this old tech. While HDDs still have their place, there are better options out there.

Solid-State Hybrid Drives (SSHDs) are a combination of traditional magnetic drives with modern flash storage technology. In a hybrid drive, you have an HDD with a large capacity as well as a special controller board with some amount of flash memory – usually 8 or 16 GB – onboard. Flash memory is “nonvolatile solid-state memory” – meaning it is made of chips with no moving parts that can store information even when the power is turned off (unlike RAM, which is erased when the power is switched off).

It’s also crazy fast. SATA (the connector hard drives used to communicate with the rest of the computer) has a current bandwidth of 6 Gbps. Solid-state flash storage can be accessed at speeds that almost hit the limits of the interface, whereas traditional mechanical drives top out at around just 200-400 Mbps – and that’s for a top-of-the-line, expensive 10,000 RPM unit!

SSHDs dynamically detect which sectors (tiny storage units) of the hard drive you access the most often (usually your operating system, most-used programs, or perhaps a few commonly-accessed documents) and copies them to the flash storage chip(s). The more you use the drive, the faster your computer gets, as it learns what it needs to access the most often and puts that information into the faster solid-state storage.

Not only are they faster, but they can provide a slight savings on battery life in some situations. They typically cost about $15-$20 more than a mechanical drive of the same size. That said, there are some concerns about their reliability. Since they are significantly more complicated than HDDs or SSDs, there is a bigger risk of failure; and we’ve seen enough failed laptop-size SSHDs that we no longer actively recommend them.

Solid State Drives

Solid State Drives

Solid-State Drives (SSDs) are the speed demons of the storage world. There are no moving parts in an SSD, they rely solely on flash storage chips. As such, they are insanely fast at all times, and they are far easier on battery life than either of the above options. Over the last few years, they’ve grown far more reliable, and can stand up to so many read/write cycles that their lifespan is approximately equivalent to a mechanical drive, assuming moderate, normal usage. To top off the list of advantages, they’re not sensitive to bumps and drops in the way that mechanical drives are (though dropping any electronic device is bad for it!)

The insides of an SSD

The insides of an SSD

They are, however, more expensive than mechanical drives – but prices are falling all the time! Some of the best SSDs in the world run about $0.30-$0.40 per gigabyte. That adds up quick, though, so most people opt for smaller SSDs than they would choose for a traditional HDD. That may not be as big a problem as you fear, though. While most new computers come with 500 GB-1 TB hard drives, the fact is that most common people use less than 100 GB storage in the lifespan of their computers, so you probably don’t really need all that space! If you really do (for example, if you do tons of video editing or downloading), and if you have a desktop computer, you may be able to use an SSD and an HDD together – a small SSD for your OS and all your programs, and an HDD for all the stuff you store.

We currently recommend the Samsung 850 Evo SSD line as the best bang for your buck.

Upgrades, replacements, repairs

If you need help, we’re here for you. We can help you upgrade to a faster or larger drive, replace an ailing drive, or, in some cases, do data recovery from failing HDDs. When a drive has failed beyond our ability to recover, a clean room and specialized equipment are required, and we happily recommend DataSavers in Atlanta, GA – they’ve got some of the best prices we’ve ever seen for forensic data recovery, and a great track record.

We try to keep common HDDs and SSHDs for desktops and laptops in stock. If you’re interested in an SSD, check out this video posted by Asus – note that it’s a four-year-old video; things are even faster now! – we also keep those in stock in common sizes, and we special-order a larger drive for you.

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