Blue and white USB flash drives, close-up (still life)Jeffrey Hamilton/Getty Images
Once upon a time, moving a computer file from place to place meant cramming it onto one, or often multiple, 1.44-megabyte floppy disks.
How times have changed.
In the age of Wikileaks, we are all becoming aware of the multitude of ways data is stored - and stolen. Each of these portable formats lets you tuck immense amounts of data into a tiny space, but also present huge security challenges. They are easy to lose, as organizations from hospitals to the military have discovered the hard way. Many are deciding encryption on such devices is now critical.
Here's a look at what's out there to store your files on the go.
First, there is the ubiquitous DVD and its predecessor, the CD-ROM. Their capacities have been far outstripped by smaller and more convenient devices that hold more than the DVD maximum of 17.08 gigabyte (double-sided dual layer). The DVD and CD-ROM still have their uses and convenience, but their day is waning.
The USB, on the other hand, remains strong as a connection medium for portable hard drives and as the carrier for flash storage. USB data keys (aka flash drives or thumb drives) are in many pockets and purses, and their capacity (it's now up to 256 gigabytes) is growing as fast as their price is falling. Today, 8 gigabyte data keys can cost less than $20.
Additional bells and whistles are available. Lexar, for example, offers USB flash drives with meters on the side showing how full they are. And for the security conscious, vendors offer encryption that creates secure data vaults to protect data in motion (a security best practice, especially since these little devices are easy to lose).
A secure vault is a password-protected space where you keep your files and folders encrypted and still work with them just like a regular file. The contents of these vaults are encrypted using the AES 256-bit encryption standard. All data placed in an encrypted vault is automatically encrypted. All data removed from the vault is automatically decrypted on the fly.
Canada's MXI ups the ante with its stealth USB keys. Not only do they hold an encrypted vault, they allow individualized security for up to 10 users, have onboard anti-virus and anti-malware software, and are waterproof and dustproof.
For the person who has everything, for $130 you can get a gigabyte LaCie Galet USB key (password protected, naturally), designed by France's Christofle silversmiths and plated in, of course, silver.
Most mobile phones, music players and cameras don't support USB devices. Instead they use tiny storage cards that slip into slots. And there are, predictably, multiple flavours of these cards, all incompatible.
First, the physically biggest: compact flash (CF). Once found in cameras and PDAs alike, its star was waning as smaller, higher-capacity types of cards arrived on the market, but it is experiencing a resurgence thanks to vendors such as Sony and Canon, who chose it as the storage media in new audio recorders and cameras. A CF card is about an inch and a half square, with a capacity of up to 64 gigabytes. Type 1 cards are pure Flash memory, while Type II are thicker to accommodate microdrives (tiny hard disks).
Moving down in size, we have postage stamp-sized Secure Digital (SD) cards. SD cards are in everything from e-book readers, tablets and laptops to cameras. Standard capacity cards hold up to 4 gigabytes; SDHC (high capacity) hold up to 32 gigabytes, and SDXC (extended capacity) can hold a whopping 2 terabytes. All three types look the same, so it's important to read the label carefully to make sure you purchase the one compatible with your device; they are not interchangeable.
Micro and mini SD cards are sub-types that are about the size of a little fingernail (micro) and just under an inch square (mini); they too are available in standard and high capacity, and can be found in mobile devices such as smart phones. Most are sold with adapters allowing them to be used as full-sized SD cards as well.
There are also less common types of removable memory on the market. Probably the best known, Sony's Memory Stick family, is a proprietary storage format that, like SD, comes in multiple versions. It is exclusively used in Sony's consumer electronics such as e-book readers, digital cameras, camcorders, music players, VAIO laptops and PlayStations. The original Memory Stick was the size of a stick of chewing gum, and held up to 128 megabytes. It is long defunct. The current Memory Stick PRO and PRO Duo are smaller and can hold up to 4 gigabytes and 32 gigabytes, respectively.