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.
- try not to do stuff on the machine while it’s writing a DVD
- 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,