Episode 58: December 19, 2012
by Eric Escobar
Christmas is almost here and many of us are still scrambling to buy last minute gifts for friends and family. That’s probably why I’ve received a ton of questions recently about specific technical jargon that may stump us when choosing which gadgets to purchase at the store or online. So in this week’s episode, I’ll be covering some of the terms thrown around the tech world that will help you compare and contrast electronics and make the best gift decisions possible. This is the second episode in my Ask the Geek series where I tackle listener questions. Check out Part 1 of this series on the Tech Talker web site.
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RPM and SSDs
Listener Nancy sent me a Facebook message about RPMs on hard drives. She wondered why solid state drives (or SSDs) don’t have an RPM speed.
This is a great question Nancy! And I’m sure other folks are wondering the same thing.
Let me break it down by explaining a few of the terms used in her question. First is RPMs. When you hear this term, your first thought is probably of your car. Well, that’s not entirely wrong! Hard disk drives are measured in the same way as your engine. RPM stands for revolutions per minute. This means that a hard drive with a speed of 7200 RPMs can spin around 7200 times in one minute.
The general rule of thumb is that the faster the RPM, the faster your hard drive will be able to recover your data. Most laptops will have a drive speed of 5400 RPMs, which is slower to save battery power. Most desktop hard drives have a speed of 7200 RPMs and some even go to 10,000 RPMs.
So why don’t SSDs have a speed rating? Well that’s because SSD stands for solid state drive. This means that the drive has no moving parts, including a spinning platter that you would find in traditional hard disk drives. Because there is nothing to spin, it wouldn’t be accurate to measure its output in RPMs.
And this raises the question: How do we measure the speed of a SSD?
I’m glad you asked! A solid state drive’s speed is measured in read speed and write speed. Read speed is how fast your computer can tell you what’s on the drive, and the write speed is how fast you record information to the disk. Generally read speed is much faster than write speed, just in case you were curious.
I know I threw a lot at you, so let’s do a quick recap. SSD stands for solid state drive; HDD stands for hard disk drive; RPM is revolutions per minute; write speed is how fast a computer can record information; and read speed is how fast a computer can recall the information on a drive. Whew!
Data Transfer Terms
Moving on to another listener question that also has some great terminology. Listener David asked me about the difference between USB 2.0, USB 3.0, Thunderbolt, eSata, and FireWire. These are all computer connections that transfer data from a computer to a device. However, each is a little bit different. Here’s the quick and dirty of these 4 connections:
You’re probably most familiar with USB, or thumb drive, as it has been adopted widely across the tech world. USB 3.0 is basically the next iteration of USB 2.0 which has a max speed of 5Gb/s, along with other improvements.
FireWire is generally used for video and has a speed of 800Mb/s or 0.8Gb/s
eSata is used mostly for connecting to external hard drives and has a speed of 6Gb/s
Thunderbolt was created by Intel and is used mostly in Apple products. It has the ability to transfer video and has a data transfer speed of up to 10Gb/s. Hence its lightning-fast name, Thunderbolt.
Bits v. Bytes
This brings me to my next clarification – and that is the difference between bits and bytes. These terms are thrown around the internet and the tech world all the time, but they can lead to substantial confusion if not used properly.
A bit is one value of information – it is either a 1 or a 0. A byte is made up of 8 bits. This distinction is huge when it comes to measuring data on a computer.
For example, when I just said that a Thunderbolt cable could transfer 10 gigabits per second, that means that it can transfer 10 billion 1s and 0s in one second. However, for reasons I’ll go into in another podcast, computers measure their data in bytes. This means that in order to find out how long it will take to transfer a file, you’ll have to divide a speed given in bits by 8 in order to convert it into bytes. So if my hard drive has a speed of 800Mb/s, that really translates to only 100MB/s. This may not seem like such a big deal, but this type of speed difference could affect any streaming movies or music if you don’t have a fast enough connection. Or if you’re comparing two different products some companies will post the amount of bits, rather than bytes in order to make their product seem better. It definitely payoff to be aware of this not so subtle difference.
This distinction is tricky and even I often forget about it when reviewing the packaging of some items I’m looking to purchase. The trick is to remember that megabits are abbreviated with a capital M and a lowercase b and megabytes are abbreviated with a capital M and a capital B.
Well, that’s it for today! Be sure to check out all my earlier episodes at techtalker.quickanddirtytips.com. And if you have further questions about this podcast or want to make a suggestion for a future episode, post your comments on the Tech Talker Facebook page.
Until next time, I’m the Tech Talker, keeping technology simple!