My cousin, Eric Burgess, over at Board Game Babylon had a hard drive crash. It happens! In fact, it ever will happen to any hard drive left in service long enough. One of my favorite scary statistics is the failure rate of hard disks – it's 100% – eventually. After I got his many gigabytes of well-organized family photos and mp3's back for him, I suggested he did not feel too bad. Nobody backs up all of the time; Seriously anyone backs up repeatedly; Most people hardly ever back up, if at all. What's in your category?
Eric's next question was – what's the best way to do backups? My answer: it depends. It depends on how much data you've got, how reliable you are at making sure you have a backup, how long you want to keep it, and the environment in which you'll keep your backup media.
There are some primary physical forms of making copies or backups of your data – removable media (such as zip disks), hard drives, optical media (such as CDs and DVDs, tape, memory stick or flash drives, and remote online backups (which I will address in a later article).
There are several ways to send your data to those physical media: a backup program, CD-burning software, the program that comes with your selected online storage provider, and simple copying of data.
Let's look at physical media first.
It used to be that there was a wide selection of removable media drives – SyQuest, Jaz, magneto-optical, and more. Now, it's primarily floppy diskettes and Zip disks. Floppy diskettes are slow, easily susceptible to damage, and hold very little data (1.4 MB). They will hold a couple of gifteds of data, but may not hold a single MP3. They are rapidly going out of style. But they are cheap and fit in your pocket.
Zip disks also fit in your pocket – they are about 3.5 "square.They come in three capacities: 100MB, 250MB and 750MB. They have had reliability problems over the years, but they continue to be around after a decade or more. Faster than floppies but slower than hard disks. They come with software that will let you lock the disk so no one else can write to it.Users from the 90's may well be shy of using them due to the old "click of death" http : //en.wikipedia.org/wiki/Click_of_death . If you've got one and it works, it makes sense to keep using it, but pay special attention to the part in this article where I talk about alternating backups.
CDs generally come in two flavors, CD-R (Compact Disk-Recordable) and CD-RW (RW for ReWritable). All flavors hold 650-700MB. Blank -R media is ridiculously cheap (25-50 cents per disk); -RW is about a buck each. If you use a CD burner (reader / writer) that was made since about 2002, it will write a disk in less than 15 minutes. A CD-R can be used once (although one may have multiple sessions); A CD-RW can be used over and over.
One of the advantages of R over RW is that you can not accidently overwrite your data. The advantage of the RW is that you can erase your data and start over. R lasts longer than RW.
How long do they last? It depends …
Longevity tests are not readily available for CD-RW media. They're not made for long-term storage. As for CD-R media, manufacturers quote anywhere from 25-100 years. Some media is rated for 217 years Right. I would not count on it. The National Institute of Standards and Technology (NIST) did accelerated testing and found that most disks would not last fifteen years and some would die in less than two.
Environment has a lot to do with how long a CD-R will last. If kept in a dry environment, at room temperature (about 75 degrees), in the dark, in a plastic jewel case, and used only once, it has a much better chance of reaching its rated life. Moisture can damage the coating on a disk (unfortunately the "CD rot" of some disks seems to have ended with disks manufactured in the 80's and 90's). Bad handling resulting in scratches – ESPECIALLY to the label or shiny side of the disk can degrade it. Air pollution is known to degrade disks. Heat and sunlight are hard on CDs. My friend Ralph Holt (of Ralph's Comic Corner fame) famously left a CD on his dashboard for years. Over time, the heat and UV twisted it into fantastic shapes. But a disk does not have to be on the dashboard to get hot. It gets plenty hot in the dark parts of a car, and in the window of your house.
Writing on disks can damage them. Scratching the top / label side of CDs or DVDs kills them. Never use a pencil or ballpoint pen – they may scratch the coating off the disk. Using a pen made for writing on CDs should be fine. Using another kind of felt tip marker may leak through the coating and damage the disk. Play it safe and use a pen made for the task – or write on the clear area of the disk near the center.
With careful handling, and a ballpark guesstimate, I'd expect half of my backup CD-Rs to last more than five years and half not to make it that long reliably.
DVDs come in several common flavors: DVD-R, DVD + R, DVD-RW, DVD-RW, and DVD-RAM. The latter three are rewritable, and like CD-RWs, are not made for long-term storage. The first two hold from 4.2GB to 8.5 GB (double layer) and seem to have lifetimes similar to CD-Rs.
I have seen no test that suggests cheap media degrades faster than name-brand media – but that does not mean that such tests do not exist. Gold-colored media is designed to be heartier than silver-colored media. I personally do not use the "noname" or house brands, but it's not based on actual tests. It's just my own personal feeling.
Writing to a CD or DVD requires a CD or DVD-burning program. There are several. Both WindowsXP and Mac OS 10 have such a program built in. There are several commercial programs available. There are many reviews available online and they do not all agree. My personal favorites have to do with speed, compatibility with my customers' equipment, and personal preference. With that caveat, I'll say that I prefer Nero on WindowsXP and Toast on any version of the Macintosh OS.
Flash drives / memory sticks are my favorite storage technology. They are getting ever cheaper, but as of this writing (mid-2007), 2GB and 4GB are the common upper end. They are so easy to use – you just stick them in the USB port of your PC or Mac. They are fast enough for storage (but not for video). They are often cute. But they are easy to lose. You may not want anyone else viewing your data – as has happened with a number of US government flash drives containing classified data I have read about in the news of late. They are also easy to leave in your pocket for the laundry. But they are darn handy for carrying data around. I do not recommend them for a primary backup because they do not yet hold a lot of data.
External hard disks are an excellent choice for backing up large amounts of data. They are fast. They are ever-decreasing in price as they increase in storage capacity. They can go from place to place. They are the only things fast enough and big enough for video. But they are very delicate. Dropping a hard disk a couple of feet could have been the end of it. A good jolt from a power surge could kill it. The backup hard disk should be external – so it's not subject to the whims of the heat and PC power supply to which your primary internal hard disk is subject. It should be shut off when it is not actively backing up data. It should be used ONLY as a backup. At the first sign of failure, it should be replaced with a new one – for your internal hard disk may fail while you're waiting for the external to come back from repair. I can not tell you how many times I've had recovery jobs come in for just that reason. Not keeping a current backup is tempting fate [http://www.datarecoveryworldwide.com/article_5_stages.html]
Tape backups are not a good choice for casual use … and possibly not for most corporate environments either. Tapes are slower, more elaborate, and require more expensive hardware than most other backup forms. For huge amounts of data, a robotic tape library costing thousands of dollars may be more efficient than alternatives
It is highly important to have redundant alternating backups. Everything breaks! Whether USB flash drive, CD, or removable media, one should always alternate backups. One scheme would be to have one disk (or tape, or flash drive) labeled "EVEN" (for even-numbered days), one labeled "ODD" and one spare. This is particularly true with removable media and tape. Of course, a CD-R can only be written to once (albeit occasionally in multiple sessions), and the scheme for a hard disk has already been discussed. But be sure that ever, something will go wrong with a backup as well as with your primary storage device.
So to review: Always have a backup of your data, daily if possible, and redundant backups are best. For the individual, tape and floppy are bad, USB flash drives are great, but limited in capacity, CDs and DVDs work well, but degrade over time. External hard disks hold a lot of data, are fast, but are delicate and are physically much larger than other forms of backup media.
Oh yes, lest I forget – ALWAYS have a backup. That's what Eric tells all his Board Game Podcast pals. I have made my living for more than 20 years recovering people's data. Do not make me have to recover yours!