FileSlinger™ Backup Reminder 6-25-04: Dead Media

Dear FileSlinger™ clients, colleagues, and friends:

I've been searching the Web for interesting items on backups and came across an article discussing the frequent failure of backup systems (due to one reason or another) and the even-more-frequent failure of businesses and individuals to have backup systems. One response written to this article was from a developer at a major storage management company, insisting that his company's products were very good and you could count on them. The further responses to this letter ran along the lines of "As if."

Then there were two articles on the subject of "dead media"—the first one arguing that because hard drive read/write speed can't keep up with processor speed, we need another kind of disk to replace them. Many programs these days resist writing to the drive in order to maintain their speed—which is part of why you need so much more RAM than you used to. (And why having programs set to autosave your files can slow you down a lot if you are working with large files.)

Writing to other media is even slower. My new DVD-writer will write to a CD at 24x, but slows down to 1x when inscribing data on a DVD-RW. (Anyone who can answer the question "1x what?" gets a prize.)

The other article discussed the obsolescence of longer-term storage media—anyone remember 5.25" disks? Since back in the days when I was an academic discussing electronic library projects with colleagues, people have been concerned that if they store their data electronically, it will be unreadable in the future, whereas writing on paper could still be read centuries from now.

Well, maybe. There are in fact fairly substantial fragments of perfectly legible ancient writing preserved on Egyptian papyrus. I got to spend one summer proofreading the printout of the newly-digitized version of a lot of them, back at the University of Michigan. But the survival of those documents depended on special conditions of climate and storage, and there are not very many people who can read the actual papyri (or even medieval manuscripts, in the case of Greek and Latin), because the style of writing is strange even to those with knowledge of ancient languages.

Most of the ancient texts we have today come to us because they were copied over and over: as one copy deteriorated, another was made. Greek texts went from papyrus to parchment to vellum to paper and were eventually mass-produced by printing press and finally scanned or typed in to electronic databases.

So it is with our electronic data. When we get a new kind of storage medium, we tend to copy our old data onto the new medium. This is just as often because the new media takes up less physical space as because we are thinking about long-term preservation. When I got a ZIP drive, I was able to get rid of a lot of floppy disks by copying them onto ZIP disks. The same holds true for ZIP disks and CDs, though before rewritable CDs became so common, ZIP disks still had an advantage over them. In most cases, we will keep moving what matters to us onto new media—and, if we still use those files at all, into new formats.

Besides, computers allow us to make so many copies, without deterioration of quality, that it becomes ever easier to make sure that some copy of a work is preserved. The challenge becomes one of having so much data that we can't remember or can't find what's there, so I will conclude by saying: label your backups.

But first go and make them.

More backup news next week,
Sallie

FileSlinger™ Backup Reminder 6-18-04: DVD-writing tips

Dear FileSlinger clients, colleagues, and friends:

A couple of times this week I had a strange experience with my DVD-writer: it would be writing merrily along and then suddenly the computer would give me a warning message and reboot. I asked the Ur-Guru, and he offered the following advice for better CD/DVD-recording results:

The real issue is; why the black screen; why the reboot, and what is really going on. My money is on not sustaining the speed to keep writing and buffers not being optimal or not having enough CPU power if other stuff is running too.

1. try not to do stuff on the machine while it's writing a DVD
2. try to turn off your screensaver and other background stuff if you are writing DVD's.

To sustain enough throughput to the DVD while writing you have to ideally NOT do any of that stuff while it's writing...you could be getting buffer underruns and nasty stuff like that (a laptop would be more prone to that given that they are slower and disks are always slower).

The "buffer" is the place the computer holds the material it's recording in memory, and if you don't have enough available RAM, then some of what you're copying could be lost (that's the "underrun" part). And it's true, I've been doing some fairly memory-intensive work this past week, in particular working on a lot of graphics. Also, the fact that my DVD-writer is external means it's slower than if it were built in.

In case anyone is wondering why laptop hard drives write more slowly than desktop hard drives: it's because they spin more slowly. A typical laptop hard drive is 4500 rpm (yes, the same kind of rpms we used to use for vinyl records), while a typical desktop hard drive is 7200 rpm. The faster it spins, the faster you can read from or write to the drive (that is, open or save files).

So why are laptop drives slower? One reason is that because the faster a drive spins, the more heat it generates, and laptops are not equipped with very good cooling systems. If the drive overheats, it can cause more problems than burnt hands for the computer operator. Also, the faster the drive spins, the faster it uses power, and laptop users generally want their batteries to last more than 30 minutes at a time.

To sum up my guru's advice in one line: don't distract your computer when it's writing to a CD or DVD.

Tune in next week for more adventures in backup,
Sallie