So as Joey mentioned last week, I’m not at our fully featured yet reasonably priced apartment this week. In fact, I’m living in a tent this week. With no WiFi. And limited Cell Service. And no power outlets. This post is as much as I could write and upload before my laptop’s battery died, so please pardon the lack of picture for the time being1Little does Joe know…hehehe. Also, a big thanks to Joey for doing the final formatting on this post2No problem, Joe!.
I’ve blogged before about how your disk drive’s role is to keep all your data safe between power cycles. I’ve also harped on how for everything but compute-heavy tasks like gaming, simulations, and video editing, the speed of your disk drive determines how fast your computer actually feels. Unfortunately, much like processors, the number you need to care about isn’t published in the adverts. Luckily, as long as you know what buzzwords to look for, picking the right drive is super simple. Today, we’ll be talking about Hard Disk Drives: old, slow, but reliable and spacious.
HDDs are based on magnetic storage: a North or South corresponds to a 1 or a 0. A stack of 2-4 small metal disks spin at either 5400 or 7200 RPM inside the durable metal enclosure. The data gets read from and written to the disk by the creatively named Read/Write Head. This part is an amazing piece of engineering that uses the wind from the quickly spinning disk to hover less than a human hair’s distance from the disk. Any further away and it can’t read the data with enough precision. Any closer and it’ll hit the disk, scratch the disk, and destroy all your data. This brings up the first downside to a HDD: durability. The drive will work just fine as long as you keep it stationary. But if you repeatedly jostle it while carrying around a laptop in a bag, all the moving parts are all points of failure. Worse, if you move the disk while it’s running, well, that human hair separation goes to data destruction real quick.
The main downside though has to do with how the disk fetches the relevant data. Because the disk is spinning, the head has to literally find the physical location of the data on the disk. After that, it can only read data as fast as the disks spin. Imagine if a book you were trying to read were written on a big spinning disk. Even if you wanted to read faster, you could only read at the speed of the disk. Worse, if you missed a word (which happens with HDDs too sometimes), you have to wait for the whole disk to come around again. For this reason, never waste your money on a 5400 RPM hard drive. The marginally higher power draw (read: slightly lower battery life) and slightly higher price of the 7200 RPM equivalent are worth it.
Also, if your data is fragmented, that is, stored in different physical locations on the disk, the RW head has to keep moving and find every bit of data. Data gets fragmented because your Drive writes to wherever there is room. Say you deleted some old poetry you tried to write years ago. Now, that space is marked as free. So when you’re downloading a new game, your drive fills up the newly freed space with the new data, then jumps to the end and finishes writing the game’s data. The game data is now fragmented, and will take a little longer to read than if it wasn’t.
This is why defragmenting your hard drive was such a big deal up until about a decade ago. Nowadays it’s not such a big deal because Windows 7 (maybe even Vista. I’d look it up but, aforementioned limited internet…) and beyond started defragmenting your internal drive automatically. So, yay.
Hard Disk Drives (HDDs) have been the standard for persistent storage for decades now, so while they definitely have downsides, there are clear benefits. First and most obvious, sheer storage space. Even the cheapest, most terrible laptops manage to find the budget for 1tb+ hard drives. I’ve seen these drives as low as $75. Desktop drives a physically larger, so unsurprisingly, drivemakers can cram amazing storage quantities into a relatively small space. I’ve seen 10tb desktop drives for surprisingly little money. If you have a lot of data to store, and only a reasonable budget to do it, HDDs are the only way to go.
I personally run 4 different HDDs for archiving in my desktop, because I’m cheap so I use whatever junk I can salvage from my work or from friends. One drive is for games and documents, two are in RAID for doubled speed for photos and videos I’m currently editing, and a final drive for long-term archiving of pictures and backups.
Hard Drives are super reliable… as long as they aren’t moved while they’re on.
HDDs are slow, but their price to storage can’t be beat as long-term bulk storage.