Tech Talk #142 – Nov 7, 2020

Before USB drives (also called thumb drives, USB sticks, and other less family-friendly names), most people backed up their computers and photos on CDs or DVDs. The U.S. Library of Congress and the Canadian Conservation Institute have each published a study estimating the useful life of data stored on CDs/DVDs at two to 100 years, depending on the disc’s storage conditions. Ideal conditions were room temperature, 50% humidity, out of direct sunlight, and no playing frisbee with the recorded discs.

If you keep your CD/DVD backup discs by your computer, they should last 20-30 years. If you have backup discs from the ’90s through the early ’20s, they may have started deteriorating to the point they are unreadable.

But how can they deteriorate? They’re plastic.

Sort of. All CDs and DVDs work by encoding the source material’s ones and zeroes on the CD or DVD’s surface. Pre-recorded discs burn a spot on the thin aluminum surface of the CD, making light and dark spots to signal a one or a zero. Recordable discs store data on a layer of photosensitive dye on top of a thin layer of aluminum to make the ones and zeroes. It’s the photosensitive dye that becomes a problem, becoming unstable and unreadable in the long run. In essence, the recorded data rots and becomes unreadable. The more expensive the blank disc was when recorded, the better the dye’s quality, and the longer it will remain readable.

If your CD/DVD backups are more than ten years old, you should back them up. Preferably to some other media like cloud storage or an external hard drive.

Many new computers don’t come with CD/DVD drives anymore, so you’ll need to pick up an external drive from Amazon or wherever you shop.

Here’s how to back up your backups. Put your old backup disc into your drive and see if your computer can read it. If so, yay! Now, copy all the files onto your computer’s desktop, keeping the same name as the disc. i.e., “Our 2002 Hawaii vacation with those people we can’t remember at all.” Once you safely copy the data from your CD/DVD to your desktop, you can copy the folder from your desktop to your cloud storage or onto your external hard drive. Repeat for your remaining CD/DVD backups.

If you find a disc too damaged to read, copy as much of the disc as possible. If you can, try to read the data on another CD/DVD drive. If that doesn’t work, you may be out of luck.

Check your Apple charges

If you find a mystery charge from Apple on your credit or debit card bill, here’s how to figure out what it is.

Any Apple charges to your card are typically from the AppStore, iTunes, or Subscriptions.

We can generally remember if we recently bought an App through the AppStore or a movie or music CD/audiobook from iTunes. But the Apple subscriptions can get lost in our brains sometimes. Luckily, there’s an easy way to track them down.

To check your Apple subscriptions on an iPhone and iPad, open Settings and tap your name at the top. Now tap Subscriptions to see a list of your current Apple subscriptions. Tap on any subscription to remind you of what or who it’s for.

To check your Apple subscriptions on a Mac, open the Mac App Store and click your account name in the lower-left corner. Click View Information near the top of the window. Scroll down to Subscriptions and click Manage. Click Edit to see more info about a subscription. You can cancel subscriptions here, too.

You should receive a notification whenever Apple charges your card. To check your setting, open Settings, and click Apple ID then Subscriptions. Make sure Renewal Receipts is toggled to on.

Spotted on Facebook (not by me)

Student: I don’t understand why my grade was so low. How did I do on my research paper?

Teacher: Actually, you didn’t turn in a research paper. You turned in a random bunch of sentences. Sentences you kidnapped in the dead of night and placed on the pages against their will. Reading your paper was like watching unfamiliar, uncomfortable people interacting at a cocktail party that no one wanted to attend in the first place. You didn’t submit a research paper; you submitted a hostage situation.

Student: Oh.

Do you have a computer or technology question? Greg Cunningham has been providing Tehachapi with on-site PC and network services since 2007. Email Greg at

Leave a comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.