When it comes to hard drives, it’s commonly said that there’s no such thing as "too big." This is true except when it comes to USB-powered drives.
To clarify: When I speak of USB-powered drives, I’m talking about ones that are solely powered by USB and nothing else. This type has no power brick to speak of. Nothing plugs into the wall. A popular example is the Western Digital MyPassport. WD has very recently released a 750GB model.
There is nothing inherently wrong with a USB-powered external drive as it does do the job it was designed to do. However there are certain considerations when using these things.
1. It’s USB 2.0. That’s it.
All you have is USB 2.0. No firewire. No SATA. USB 2.0 has a throughput that is slow. With smaller files you won’t notice the slow transfer speed, but with larger files this will stick out like a sore thumb. You will particularly notice this when transferring anything over 50MB in size.
2. For any individual file over 4GB in size, you must format as NTFS.
FAT32 can only handle a maximum individual file size of 4GB. That is a design limitation of that partition type. If you plan to push DVD images (which easily go over 4GB) to one of these external drives, NTFS is required.
3. Risk of file corruption increases.
Due to the fact that large file transfers take so long, you’ll probably be doing other things on your computer while file copies are taking place. This is not a smart idea. When performing file transfers of large files, you should dedicate the computer to it until it’s complete.
Transferring large files via USB 2.0 does properly work as long as you don’t interrupt the process.
Think of it this way: When you’re burning a CD or DVD, you ordinarily let that task remain in the foreground until it’s done. Follow suit when transferring files to the external USB-powered drive.
Also, it is an absolute requirement that the drive is "safely" mounted and unmounted no matter what operating system you use.
4. The drive must remain stationary while in use.
Large-sized USB external drives are not SSD. These things house regular 2.5-inch laptop-sized drives. As such, don’t move it around when in use. You may be tempted to do so but I don’t recommend it. Yes it can handle gentle movements, but the wrong move while a file transfer is in place and this can lead to corrupt files in short order, or worse yet a drive failure.
Why can SSD be moved around without fear of them breaking? Because there’s no moving parts. Normal 2.5-inch drives on the other hand do have internal moving parts and that’s why you keep them motionless when in use.
As long as you keep realistic expectations, external USB-powered drives will work for you.
When you are aware that:
- Large files will transfer slowly
- Mounting and unmounting no matter the OS must be done properly
- When copying large files, don’t do anything that would interrupt the process
- When the drive is in use, keep it motionless
..external USB-powered drives will work just fine.
On a final note, I don’t want to give off the impression that USB-powered external drives are fragile little things, because they’re not. They are built to modern specifications and can "take a beating", so to speak. Just be aware of the USB 2.0 throughput limitation and the fact that yes, there is a 2.5-inch HDD whirring inside the thing that’s not meant to be banged around, and you’ll be A-OK.
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PHiLOS
1252 days ago
Good points Rich – well worth bearing in mind. I have a client who backed up a lot of SQL data to a 250GB Passport drive and one day I saw him handling it carelessly, like it was indestructable – wasn’t suprised when he called up in a blind panic because it stopped working one morning. Suffice to say, as is the the way with all these things….lesson learned!
Rich Menga
1252 days ago
It’s a truth that you can’t just bang those things around. The product gives the illusion that there are no moving parts inside when in fact there are. And yes, some learn their lessons the hard way concerning this.