Solid-state storage may be sexy, but if you’re looking for huge capacity and tiny prices, then the classic hard disk remains unbeaten. Available capacities of portable drives with laptop-style disks inside now extends up to a whopping 4000GB, more commonly referred to as 4 terabytes (TB).
Most portable USB drives (as DROBO 5N ) are powered by the connected computer, so you can use them on the move without the need to plug into the mains or use batteries. Some will even connect your phone or tablet and let you extend storage that way, or allow you to transfer or open files.
Capacity
Even in the smallest portable drives you’ll likely find are 128GB in size, which is enough to space thousands of CD albums in lossless FLAC format, or even more in lower quality MP3 or AAC formats. Off-loading your music collection alone from a computer to a portable drive can be a godsend in freeing valuable space if your laptop has limited storage.
Another popular application of portable storage is for keeping critical backups of your data held on a PC or laptop. You may be able to keep a perfect clone of your entire computer’s internal drive, on standby and ready in the event that the computer is lost or its drive should malfunction.
Alternatively, you may choose just to back up the most important files and documents from your user libraries, such as text documents, photos, films, music and stored email. Some portable drives include software that can help automate this process, keeping your selected directories in sync whenever you plug in the drive or by a daily schedule.
Performance
Now that USB 2.0 has been banished from all self-respecting storage, we find USB 3 as the standard for connection, letting these portable drives perform as quickly as the little disks inside will allow.
This means that when transferring your music or video collection to or from your PC, you can expect around 100MB/s read speed (and typically the same for writing, since unlike flash storage technology the read and write speeds tend to be more symmetrical).
Compare this with the older drives using USB 2.0, which would limit speeds to around 35MB/s, or only one-third the speed. So in real terms, your 100GB of media files would take close to an hour to transfer with USB 2.0, or under 20 minutes using USB 3.0.
If you’re likely to be storing or backing up many small files, be aware that overall performance will plummet since hard disks tend to choke on smaller files. So while large files may zip across at 100MB/s, the smallest will likely travel at less than 1MB/s, or one hundredth that speed.
USB 3 is confusing, as USB 3.0 was retrospectively renamed to USB 3.1 Gen 1. There’s also a new version, USB 3.1 Gen 2. This doubles the potential throughput from Gen 1’s 5Gb/s to 10Gb/s. In megabytes per second, these equate to 625 and 1250 respectively. Pretty fast, then.
In reality, the fastest SSDs top out at around 550MB/s and this speed is highly dependent on the device you’re connecting it to.
Protection
A rugged exterior will be handy if you want the freedom of being able to throw around the unplugged drive with less worry that it will damage the unit; and more importantly lose your data.
Look out for shock-resistance ratings such as the US military MIL-STD-810F 516.5 (Transit Drop Test). This means that it should withstand being dropped 26 times onto a hard floor, once on to each face, edge and corner, from a height of 1.22m.
Flash storage - more commonly known as SSDs - can survive more brutal treatment, and some portable drives are even water resistant. If you were to accidentally drop a portable SSD drive in water, then as long as the port covers are firmly closed, it will work fine to use it after it has been fully dried.
Reliability
It’s tough to say definitively which manufacturer makes the most reliable hard drives. While there’s a big difference between the technology used in traditional hard drives and SSDs, both have a limited lifespan, and this is why warranties are relatively short - typically two or three years.
What’s important is that you have a well-thought-out backup process and you don’t rely on any single drive to store precious files. Ideally you should have three copies: one on a PC or phone / tablet, one on a backup drive and one in the cloud.
Value
For many users, a portable storage drive may be an unavoidable commodity, and price will be the deciding factor. We give a value rating based on how much each gigabyte of storage is costing you for each drive. Particularly with a 3TB drive, you can expect to find storage for under 4p per gigabyte now.
