Everyone knows they need to back up digital media and work material, and curse themselves when they get caught without one and lose some files. The two big questions? How, and how much. The two best answers? Automatically, and free or darn cheap.

Copying files to a second hard disk or disk partition in your computer will help you recover from a crashed or corrupted hard disk. Copying files to an external hard disk or USB drive will do the same. But when your computer gets stolen or your equipment gets flooded or otherwise damaged, you will wish you followed the two cardinals rules for successful file restoration: backup automatically, and backup offsite.

How Online Backup Services Work
The new breed of online backup services provides automatic backup, and stores your files hundreds or thousands of miles away. These actions require software on each client using the backup service, good broadband upstream bandwidth for uploading files to the service, and at least two ways to retrieve files from the service.

Software on each backup client can easily be downloaded and installed from the service. Each service provides their own backup software you must use, except for one exception mentioned later. If you change services, you must change software.

Not every file gets copied to the remote service. By default, system files (.EXE and .DLL) are excluded, as are temporary files and hidden files. Each service provides a basic backup profile, primarily your My Documents and Documents and Settings folders, and makes it easy to add other data folders.

Your entire set of backup files must be uploaded to the service at the beginning, and this takes time. Although the services upload in the background, any computer activity will suspend or severely slow uploads. Figure about 1-2 GB per night for upload speeds, although some services claim you can upload as much as 9 GB overnight. Since US broadband providers restrict upload speeds compared to download speeds by as much as a factor of 10, be patient.

Transmission over the Internet through your broadband carrier will be encrypted with at least 128-bit security protection, similar to what e-commerce sites use. Once on the remote site, your data will be encrypted with at least 256-bit file encryption, although most services offer higher levels of encryption security. Services won’t lose your files or suffer data breaches, but if that does happen, unless the hackers break extremely high-end encryption security, your files remain private.

Most services offer at least two options for file restoration or downloading: through the client software and through a Web interface. File restoration to the original computer happens most easily through the restore option in the client software. However, for sharing purposes or for file transfer to systems not using the service, a password-protected Web access portal can be used. This features works well for transferring files from your home computer to the office, for example.

Once properly installed and configured, the online backup services work automatically and in the background. You may catch yourself wondering about the weird icon in your Taskbar after a while, and then realize you have an online backup service running.

Working Around Online Backup Limitations
Online backup services are good, but they don’t cover every backup and restoration situation. Obviously you need a broadband connection to upload your files, or an enormous amount of patience. All major online backup services support only the Windows operating system, although Mozy.com now offers a beta of Macintosh client software. And these systems do not provide Bare Metal Restore options, where a single prepared CD installs a stripped-down operating system to get your computer running well enough to start the full restore process.

Open files cause all backup processes grief, but home users shouldn’t be running Microsoft Exchange Server, a constant problem for business backup. However, if you use Microsoft Outlook (not Outlook Express) as your e-mail client, you will need to close Outlook to properly backup your mailbox. Restoration means downloading your entire Outlook data file (.PST) rather than individual e-mails.

Online Backup Services Shopping List
Many services offer a block of space for free (usually 2-5 GB). Other services charge from your first saved byte. All offer at least 15 days for a trial to convince you to sign up for the service.

The major players are:

• Mozy.com—2GB free
• Carbonite.com
• JungleDisk.com –- A front end for Amazon’s new S3 storage service. It may work with your existing backup software.
• iBackup.com
• Xdrive.com -– Remote storage service now offers a backup feature

Google ”online backup” and you’ll get millions of responses. Yahoo’s directory listing shows scores of backup service options as well, with explanations and quick links to each.