You've been through this before. A smart-aleck technology columnist tells you to back up your computer files or else. Sure enough, you choose "or else," because making spare copies of your files is too much bother.
You don't want to spend $100 or more on an external hard drive or figure out how to install the automatic backup software. Besides, if your house is robbed or burnt down, there goes your computer and your precious backup, too.
Unless your backed-up data wasn't home when disaster struck.
These days you can copy your files over the Internet, and store them at a high-security data center, with help from an online data backup service. Not many consumers presently use online backup - only about 1.5 percent, according to a survey taken last year by research firm IDC Corp. in Framingham. But lots of companies offer online storage for small amounts of data, often at no charge. Two firms promise to store every file you've got for as little as $50 a year.
Both of them have a Bay State connection. Last year, EMC Corp. in Hopkinton purchased Berkeley Data Systems, a Utah company that offers Mozy, an online backup service for consumers and businesses. Meanwhile, in Boston, a homegrown outfit called Carbonite has offered online backup since 2006. Based on our tests, you can't go wrong with either Mozy or Carbonite, but we'd give Carbonite the edge, thanks to its brain-dead simplicity and slightly lower price.
Carbonite costs $49.95 a year or $89.95 for two years of service. Mozy's consumer service, MozyHome, charges $4.95 a month, or $59.40 a year - but you get a free month's service if you pay for a year in advance. In exchange, both companies say you can back up as much data as you wish. Mozy also offers a free service that's limited to two gigabytes of data - next to nothing in the era of digital photos and MP3 music files.
In our tests, we uploaded 55 gigabytes to Carbonite and about 40 gigabytes to Mozy.
Obviously, both services require that you have a high-speed Internet connection. A dial-up link is far too slow for backing up this much data.
You must download and install a little program on your computer to oversee the backup process. For now, Carbonite offers only a version compatible with Microsoft's Windows operating system. The company says it's working on software for Apple's Macintosh machines and expects to offer it by May. MozyHome already has a Mac-compatible version.
Even though the Mozy and Carbonite software runs at all times, there was no discernable impact on the performance of a Windows PC. Each program automatically throttles back when you're using the machine, to ensure that it doesn't interfere.
You can use the software to identify the files you want backed up. Generally, you shouldn't include the operating system or software applications; you should have saved the original installation disks for those. Instead, back up only the irreplaceable personal files you've put on the machine. On Windows computers, these usually wind up in the Documents and Settings folder. Both Mozy and Carbonite will back up this folder automatically.
The waiting is the hardest part. High-speed Internet connections won't let you upload data nearly as fast as you can download it. It took about 10 days, with the computer running round the clock, to back up 40 gigabytes of data over a Verizon DSL connection.
Restoring the same amount of data would take a couple of days, because downloads are much faster. Besides, that first big backup is only done once. After that, Mozy or Carbonite will simply wait for you to add new files, or make changes to existing ones. At regular intervals, the programs will run incremental backups to capture these changes. You can order the programs to make immediate updates, or set a backup schedule.
Both Mozy and Carbonite offer "versioning," to let you track changes in frequently modified documents. Say you're writing the Great American Novel. Every day's work gets backed up into a new version of the file. Now you can download a previous day's work and compare it to your latest efforts.
Mozy and Carbonite both encrypt your data to protect your privacy.
Mozy pioneered an extra feature that lets you pick your own encryption key, one that even Mozy can't crack. It's the ultimate in privacy; even if the government subpoenaed your files, Mozy would be unable to comply. Carbonite has recently added the same service.
But beware - if you choose your own key, and then lose it, no power on earth can restore your files. For users with nothing to hide, both companies recommend the standard encryption system.
Given their nearly identical features, either Mozy or Carbonite will get the job done.
But Mozy is beset with a relatively geeky user interface and a tendency to throw up unexpected and confusing on-screen messages. Company officials admitted that they need to make their software more user-friendly. On that score, Carbonite is just about flawless. Just install it, launch it, and forget about it. And the next time some annoying columnist nags you about data backup, just skip to the sports page.
Hiawatha Bray can be reached at firstname.lastname@example.org.