PC storage & backup: Your questions answered

You probably missed it, but 31 March this year was World Backup Day. We can't see it ever rivalling Christmas Day as a day of celebration, but it does serve as an important reminder that we're all potentially just one hard-drive failure away from losing our most precious files. And you have to admire its pledge: "I solemnly swear to back up my important documents and precious memories on March 31st".

We store thousands of documents, photos and other files on our computers and devices without really thinking about it. Running out of space affects pretty much everyone at some point, and it can be a massive hassle when you need to decide which files to delete to make more room. You can insure yourself against these problems, but it's also easy to make mistakes.

In this manual on PC storage and backup, we recommend the essential tactics for keeping your files safe, and reveal the errors to avoid.

What's the difference between memory and storage?

They are often used interchangeably but the two concepts are somewhat different. With PCs, 'memory' usually refers specifically to your computer's system memory (or Ram), whereas 'storage' usually refers to a hard drive (or similar device). And, in practical terms, these components fulfil quite separate functions.

The easiest way to differentiate between them is to think of memory as short-term storage and your hard drive as long-term storage. Files stored on your computer's long-term storage drive remain there until you delete them, even after you've switched your device off.

Memory is only used as a temporary storage space for files, programs and other data while you work. Open a photo in an image-editing program, for example, and it's temporarily loaded into your computer's system memory for you to work on.

How is storage measured?

Storage devices are measured by their capacity in bytes units of data and multiples thereof. A kilobyte (KB) is 1024 bytes, a megabyte (MB) is 1024 kilobytes and so on. These days, most hard drives are measured in gigabytes (1GB = 1024MB) and terabytes (1TB = 1024GB).

Annoyingly, however, the storage measurements advertised by manufacturers don't equate exactly to the amount of storage reported by your operating system. This is because computer data is measured in binary and, at some point, hard drive manufacturers decided it would be more helpful for customers if storage capacities were quoted in standard decimal numbers instead.

Endmemo's calculator tells you the real capacity of your hard drive

Thus, a kilobyte becomes 1000 bytes, a megabyte translates to 1000KB and so on. What this means in practical terms is that manufacturers' capacities are usually exaggerated. For example, a hard drive that quotes a 1TB capacity will only actually offer just over 931GB of real storage. You can use Endmemo's handy calculator to convert manufacturer capacities into genuine amounts.

What are the different kinds of storage?

The most common type of computer storage device is the hard disk drive (HDD for short) a mechanical device that stores data on magnetic platters. Hard drives come in two main types: internal and external. Internal drives need to be fitted inside PCs, while external drives can simply be plugged into a spare USB port.

SSDs are a newer, faster type of storage device that fulfil a similar function to traditional hard drives, but use solid-state storage electronic circuits with no moving parts instead of mechanical components. NAS (network attached storage) devices are a little like external hard drives, except they don't connect to a single computer via USB. Instead they connect to your network and let you access files from any device.

There are also a number of different useful portable storage media, including USB sticks (also called flash drives) and SD cards, that let you share files between devices. Capacities range from 64MB to 64GB and beyond. Confusingly, these types of device use something called flash memory to store data, but it's still more correct to refer to these as storage, rather than memory.

What are the main benefits of SSDs and HDDs?

If you're looking for maximum capacity and minimum price per GB, traditional hard drives are hard to beat. A 1TB internal drive such as a WD Blue 1TB Desktop Hard Drive should cost you less than 40 online these days (available on Amazon for 37.61 when we last checked), whereas a 1TB SSD could set you back anywhere up to 350, depending on the make and model.

1TB hard drives like the WD Blue now cost less than 40

External hard drives tend not to cost much more than internal ones their affordability and removability make them ideal back-up devices.

The key advantage of SSDs is speed. Replacing an older PC's internal hard drive with an SSD can radically improve start-up times, and boost overall speed. Prices are higher than traditional hard drives, but they're beginning to drop to affordable levels, particularly at lower capacities. For example, a 120GB SSD such as SanDisk's SSD PLUS can breathe new life into a flagging PC for just 36.

Hybrid drives like Seagate's FireCuda combine fast SSD speeds with large HDD capacities

If you want the best of both worlds, you could consider a hybrid drive, such as the Seagate FireCuda, which uses a combination of SSD and HDD technology to offer both a speed boost and a large capacity at a reasonable cost (60 for 1TB on Amazon). Alternatively, you could consider buying a small, cheap SSD to use as your main system drive, then re-using your old HDD (or buying a newer, large capacity drive) for storing photos, music and other files.

How much storage do you need?

When choosing a PC (or any other device) it's always a good idea to overestimate the amount of space you'll need. File sizes tend to increase over the years high-resolution photos and HD video from today's digital cameras, for example, take up much more space than their lower-resolution equivalents would have done a few years ago. Programs, apps, games, music and updates all consume space, too.

Yes, it's possible to clear up your hard drive and make room. And, yes, it's usually possible to add more storage at a later date. But you'll save yourself a lot of stress by giving yourself room to manoeuvre from the outset.

It's hard to put an exact figure on it, since everybody's usage levels are different. But generally we'd suggest 500GB should be about right for a light PC user (someone who surfs the web, creates documents and edits a few photos), while anyone who uses their computer a little more heavily (to edit video, for example, or play games) should consider at least 1TB.

In addition to your PC's 'working' storage, you'll need some backup storage space as well. You have some options here but, as a rule, it's a good idea to have a backup solution that provides at least the same amount of storage as your PC's built-in drive. Depending on precisely how you decide to back up, you may need even more space.

What exactly can I back up?

Almost everything on your PC can be backed up in some way. The most common types of backup tend to focus on making copies of your personal files documents, photos, music and so on. This is sometimes referred to as a file-and-folder backup, and it's the best way to safeguard your files against damage or data loss.

But you can also create something called a system image backup, which is essentially an exact copy of everything on your PC's hard drive, including Windows' system files and all your programs. This can be used to restore your whole PC in the event of a more widespread problem, such as hard-drive failure.

Windows 10 has built-in tools for both file-and-folder backup and system image backup, and there are lots of non-Microsoft programs that can do both, too.

What kinds of storage are now obsolete?

Floppy disks were used extensively between the 1980s and the early 2000s, but are now more or less extinct. It was already going the way of the dodo when Windows 10 arrived in 2015 without built-in support for USB floppy drives. That hasn't stopped manufacturers from producing floppy devices, though, and you can still pick up Windows 10-compatible USB floppy drives cheaply online, such as this 11.95 model from Amazon.

Also on the endangered list are CDs and DVDs. At one point, CD-R's 650MB seemed like a lot of space, but even DVD-R's 4.7GB feels pretty cramped these days. Optical discs were once thought of as the pinnacle of convenience but, for some people, the idea of waiting while data is 'burned' to disc seems laughably archaic. Of course, millions of people still listen to music on CD and watch DVDs, so optical drives aren't extinct yet, though their days are probably numbered.

Tape drives, Zip disks and punch cards are among the other exhibits you'll find in the museum of forgotten storage formats here.

Image: Shutterstock