DV BACKUP MAKES IT EASY
Backing Up Is Hard to DoBy MIKE PASINI
The Imaging Resource Digital Photography Newsletter
Review Date: April 2004
Backing up was simpler when it didn't involve gigabytes of data. Much simpler. Now it practically requires a U.N. resolution.
So we've kind of given up on the possibility. We bought a "little" 30-GB FireWire external drive and just copy everything over to it once in a cyan moon. We boot from it just to prove we can and then ignore it (except for ephemeral but crucial files like our newsletter drafts) until the moon shines cyan again.
Meanwhile, we back up more permanent data like our digicam images to CDs. Unfortunately, this seems to require hours with on-site and off-site copies and duplicates for the on-site copies. One night we caught ourselves watching the CD burn, waiting for the Verify button. Had we really nothing else to do?
LOW TECH SOLUTION
That's when we realized this is exactly what great literature is for.
So in the last few months, we've dusted off our copies of several intimidating tomes to pass the time while our backups were running. It's been a surprisingly gratifying experience.
First, we've found modern stuff rarely works. You need old stuff. Old stuff is long, first of all. But it's also bite size. A whole chapter can be consumed during a burn or a verify. How'd the ancients know?
Second, let us recommend a few beauties for your consideration:
- English readers can avail themselves of Bosworth's Life of Johnson. A couple of hours of this refined prose and you'll be unable to resist the temptation to speak funny, but that beats thinking funny.
- Italians will no doubt appreciate reading Manzoni's Betrothed. It's one of those things you're supposed to have read, but who has the time? You do -- when you schedule a backup. Read this poor couple's trials and tribulations and your cares will be comedies.
- Aficionados of Spanish will appreciate Cervantes' Don Quixote even more as they wait for their backup to pretend some integrity. What's more like a knight errant than a security patch? Who more like Sancho Panza than the innocent who clicks "OK?" And Edith Grossman's recent translation makes it work for English readers, too.
- And Chinese readers will appreciate Gao Xinjian's Buying a Fishing Rod for My Grandfather. It's a real short book but there's no plot to any of the stories, all of which require continual rereading, much as if you have to keep backing them up to your mind.
HIGH TECH SOLUTIONS
Not every situation lends itself to our low-tech solution. Reading Boswell on the job could accelerate your layoff, for example.
For years we relied on Dantz's Retrospect (http://www.dantz.com), which could copy not only our system to digital tape, but anything on the network, too. On the rare occasions we needed an old file, it delivered. But it was pretty complicated. And when we changed operating systems, it didn't come along for the ride.
By then we were in gigabyte territory and had no SCSI port to connect our tape backup device anyway. So we started reading in earnest, using our external drive for system and temporary backups and CDs for final data backups.
Why didn't we try an online backup service? Well, copying gigabytes of data over even our broadband connection didn't appeal to us. We weren't fooled into thinking an offsite backup under someone else's control was the same thing as having both an offsite backup and a local backup, both under our control. The point of a backup, after all, is access. You don't want someone else controlling it.
But last summer we stumbled across a really clever solution for Mac OS X users (although why some virus-writing adolescent doesn't adapt the open source code gnutar on which it's based to Windows eludes us). It's DV Backup by Tim Hewett at Coolatoola.com (http://coolatoola.com).
Hewett's solution was to use his 1999 Digital8 Sony DCR-TR7000E as a tape backup device. After all, it writes digital (not analog) data to inexpensive media and easily connects to a speedy FireWire port. And it's portable.
FireWire cable, Camcorder, Tape
If you're running OS X (Jaguar or Panther) and have a digital camcorder that uses DV or Digital8 format tapes (either PAL or NTSC), you too can back up to your camcorder.
The evaluation version lets you do everything except multi-tape backups. It limits you to a 1-GB backup on the first run, 50-MB for subsequent runs and no more than three backups per tape. It also lets you test your camcorder for compatibility before spending $25 on an access code good for all version 1.x updates.
When recording video, the occasional blip (say, from a defect in the tape) isn't a problem. That same little tape error in your checkbook data can make you of unusual interest to the IRS, however. Any backup program, consequently, has to provide error protection and correction.
DV Backup does it by recording fixed-sized data blocks of about 10K. For each block of data, it can, after performing some math, record data useful for error correction. If there's an error in the original recorded block, Hewitt explained, "the error correction chunk can be used with all the other data chunks to reconstruct the one which was corrupted."
The program offers different levels of error protection. A 1:1 ratio provides complete error protection for each data block. But it also uses half the tape for error protection. You can select less error protection, designating that one block of error protection data protect, say, four or six data blocks. That uses less tape, but it can only correct one data block. So if more than one error occurs, none of the data can be corrected.
DV Backup can record in SP or LP mode. We expected that SP, which uses more tape for the data, would be more reliable. But in practice "only one existing user has reported having any difficulties using LP mode and most use it exclusively without any problems," Hewett noted.
Count on 15-GB per hour of tape in LP mode and 10-GB per hour in SP mode.
The level of error protection you select affects the time it takes to make the backup. But even the fastest backup will send you to the bookshelf. With no error protection, you can transfer about 1-GB every six minutes. With full protection (duplicating all the data), the same data takes 12 minutes.
Network backups are possible, too. Hewett said that data is streamed to and from the camcorder at 3-MB/sec. "Many 100-Mbit networks will keep up with this without any problem assuming they are not heavily used by others at the same time." But that's too fast for CD-ROM and DVD-ROM drives or USB 1.2 devices. Hewett simply recommends copying data from those devices to your hard drive to back it up.
No, camcorders were not designed as backup devices. Does reading and writing data to them hasten their ultimate demise?
Last summer, when DV Backup first came out, this was a theoretical discussion. But the jury is in. Hewett said his Sony, used for thousands of backups during development, "has never had a problem and continues to restore data from tape with a very low error rate. No other user has reported any problems."
We're inclined not to worry about it. Our old tape backup device was a good deal less sophisticated than the hardware in our camcorder and it functioned reliably for years.
Your camcorder provides its own source of power, using either its internal battery or household current. We prefer to plug it into the wall, but we also like to have the battery charged in the event of a power failure. Backups take too long to do twice and you can't read in the dark.
Make the FireWire connection just as if you were transferring video to iMovie. Connect your camcorder, switch your camcorder to VCR mode and start DV Backup.
If you haven't confirmed your camcorder's compatibility, run the camera test to confirm whether DV Backup can control your camcorder via FireWire.
When you pop in a tape, DV Backup scans the first 20 seconds of the tape (after rewinding, if necessary) to see if it's new. When it detects a new tape, it requests permission to format it. You're prompted for the tape length, tape name and the recording format (Normal or Strict, which is useful for JVC camcorders).