Hard drive buying guide

We walk you through the process of buying a new hard drive, and explain all the jargon: from network-attached storage to solid-stated drives

Hard drives can be found in all sorts of products — PCs, digital video recorders (DVR), camcorders and MP3 players, for example. The hard drive is one of the most important components for PCs, as it provides permanent, large-scale storage for a user's documents, pictures, videos and other data.It's also where the operating system and programs are stored. Unlike memory (RAM), hard drives retain information even when the PC is powered off.

If you're buying or building a new PC, or have simply run out of space on your existing PC and need to boost your storage capacity, knowing what to look for in a hard disk is vital.

How do hard drives work?

First employed commercially in the 1950s, a conventional hard disk comprises one or more circular platters of magnetic material, with billions of microscopic magnetic domains, each representing one bit of data. These zones are embedded into concentric circles, called tracks. A read/write head floats above the tracks, and the magnetic flux patterns of the zones affects an electric current flowing through the head, which in turn registers as a "0" or a "1" to the drive's electronics. The head can also alter the magnetic patterns, to write data onto the disk.

When in operation, an electric motor spins the hard disk constantly, rather like an LP or CD, in order to bring the data on the tracks around to the head. The head moves across the surface of the disk, to position it above the track on which the desired data is stored. The head will then wait for the rotation of the disk to bring the data around.

A "hard disk", as we understand it today, will usually comprise multiple platters (typically between two to four in a standard consumer hard disk). Modern hard disks can vary in size from 1in wide for smaller personal media players to the more commonly available 3.5in hard drives for desktop computers.

What is a solid-state drive?

A recent trend in the storage market has seen a slow shift toward a new type of permanent storage: the solid-state drive (SSD). Unlike hard drives, which have moving parts and are more prone to being damaged if dropped or bumped, solid-state drives don't need magnetic plates and hard drive heads.

These drives work by employing solid-state SRAM or DRAM memory to store information, like the memory modules which make up the RAM in a computer. However, unlike RAM, which loses its stored information every time a computer restarts or shuts down, an SSD uses non-volatile memory.

Join the newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection

Tags storagenetwork-attached storagesolid-state drivesbuying guidehard drives

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

PC World Staff

PC World
Show Comments

Cool Tech

Breitling Superocean Heritage Chronographe 44

Learn more >

SanDisk MicroSDXC™ for Nintendo® Switch™

Learn more >

Toys for Boys

Family Friendly

Panasonic 4K UHD Blu-Ray Player and Full HD Recorder with Netflix - UBT1GL-K

Learn more >

Stocking Stuffer

Razer DeathAdder Expert Ergonomic Gaming Mouse

Learn more >

Christmas Gift Guide

Click for more ›

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Edwina Hargreaves

WD My Cloud Home

I would recommend this device for families and small businesses who want one safe place to store all their important digital content and a way to easily share it with friends, family, business partners, or customers.

Walid Mikhael

Brother QL-820NWB Professional Label Printer

It’s easy to set up, it’s compact and quiet when printing and to top if off, the print quality is excellent. This is hands down the best printer I’ve used for printing labels.

Ben Ramsden

Sharp PN-40TC1 Huddle Board

Brainstorming, innovation, problem solving, and negotiation have all become much more productive and valuable if people can easily collaborate in real time with minimal friction.

Sarah Ieroianni

Brother QL-820NWB Professional Label Printer

The print quality also does not disappoint, it’s clear, bold, doesn’t smudge and the text is perfectly sized.

Ratchada Dunn

Sharp PN-40TC1 Huddle Board

The Huddle Board’s built in program; Sharp Touch Viewing software allows us to easily manipulate and edit our documents (jpegs and PDFs) all at the same time on the dashboard.

George Khoury

Sharp PN-40TC1 Huddle Board

The biggest perks for me would be that it comes with easy to use and comprehensive programs that make the collaboration process a whole lot more intuitive and organic

Featured Content

Product Launch Showcase

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?