[MacDV] Re: Drives Vs DVD's for long-term accessible storage--MacDV Digest, Vol 6, Issue 9

[Gregg Gorrie]

on 1/9/05 2:00 AM, Ted Langdell at ted at tedlangdell.com wrote:

> Oh, and DVD's?  Who's sure how long they're going to be stable,
> recoverable?  You're better off if you burn at 1X speed, for a "deeper"
> longer-lasting backup, according to what some folks are reporting.

In terms of both short and long term storage, I will put my money on DVDs
versus hard drives. You will save a couple of steps and time saving the data
to a hard drive only, but stability is paramount for an archive.

1) Hard drives are a read/write media ...inherently the second you hook the
drive up to your computer, there is the potential for disaster. I know this
all too well from personal experience. After spending several hours
capturing video onto my FW hard drive at work, I immediately took it home to
edit. Hooked up my FW drive to my computer and got the message "data on the
drive may be corrupted" and it wouldn't mount. I tried every trick in the
book (Disk Warrior, Data Rescue, Disk Doctor, etc.) and was unable to
recover that data. When this happened the second time, I did several days
(weeks?) of troubleshooting and to make a very long story, the corruption
would happen whenever I hooked up the drive running OS9 (on my computer,
even though it was captured in OS9 at work), but was OK with OSX, perhaps an
issue with the disk driver or my FW card? The point is that data on hard
drives is extremely volatile.

Once you burn a DVD-R, it is a read-only media. The drive itself can't
corrupt the directory or erase the data (unless it a DVD-RW).

2) Hard drive formatting tends to be OS/platform specific, which means if
you store your data on a Mac formatted drive it can not be natively read by
a Windows machine and vice versa. There are utilities out there (MacOpener,
Apple File Exchange, etc.) which aim to smooth this out, but in my
experience it is a very rocky road trying to get media formatted to
read/write (without snags) on multiple OS/platforms. What about in ten
years?

A DVD formatted as UDF or ISO 9660 is very cross-platform compatible - my
late 1980's Atari Falcon can read ISO 9660 disks, as can Macs and PCs. This
may be an issue in the future as operating systems change and you may not
have the computer/OS you had when you originally captured the footage.

3) Physical properties - if you drop a hard drive and a DVD disk from three
feet off the floor, which one would you put your money on to survive the
accident? Hard drives are very susceptible to mechanical shock damage, and
as magnetic media can be affected by short term exposure to highly magnetic
fields (close proximity to loudspeakers, computer monitors, etc.) and/or
long term exposure to low level magnetic fields (the above factors at a
distance, earth's magnetic field).

The primary Achille's Heel's of DVD media are exposure to light and
scratches, both of which are fairly easy to manage (keep the disk in its
case!!) One other thing to watch for however - the flexing that can happen
when you try to remove the disk from a sticky case can cause problems. DO
NOT bend the disk as this can cause separation of the layers within the
CD/DVD and could lead to early failure. Try to find cases that have the
button which releases the disk from the case easily.

To sum up, there isn't any backup/archival media which is perfect so take
appropriate care of whatever you do use. And to reiterate my previous post,
REDUNDANCY is perhaps the greatest insurance you have to avoid total loss. I
tell my student's that they shouldn't even consider that their projects are
completed until they have them backed up in AT LEAST two different places.
Many of them still have had to learn the hard way, just as I did ... ;).
-- 
Gregg

PS I agree with Ted about burning CD/DVD media at slower speeds - there
seems to be growing anecdotal evidence supporting this.