Personal computers are changing in ways that go beyond even the more recent innovations, such as the launch of Windows 7: Several of today’s laptops are missing a familiar component, computers can be controlled in various new ways, and portable PCs are slimming down.

Even with all the attention lavished on Apple’s iPhone and Amazon.com Inc.’s Kindle this year, a PC or laptop still is likely to be the center of a student’s digital universe. Here’s a look at what this year’s computer trends mean for the personal computing–and especially for education.

• Drives are becoming a thing of the past.

Computers have come with “optical drives,” slots for CDs or DVDs, for years. They’ve been useful for installing new software, watching movies, or transferring music libraries into digital form. But one of the biggest lessons from the craze for netbooks is that people were so excited about the small, easy-to-carry size that they didn’t miss having a CD or DVD drive. And students who use school-issued machines primarily for word processing and accessing the internet aren’t likely to miss such a drive, either. (Plus, it’s one less way unwanted software can invade the machines.)

Apple Inc. got rid of an optical drive two years ago when it introduced the first sliver-thin MacBook Air. That wasn’t seen as a trendsetting step at the time, because the computer–which cost $1,800 then–wasn’t meant for mainstream consumption. But netbooks, which start as low as $250, are made for everyone.

The tiny laptops’ popularity is proof that people are finding it easy enough to download software, movies, and music to portable computers, especially with the widespread availability of Wi-Fi and cellular internet service. And plenty of services let users store files over the internet, eliminating the need to burn backups to discs.

Taking out the optical drive doesn’t significantly lower prices. But doing so does let PC makers design much thinner laptops. Companies such as Dell Inc. and Hewlett-Packard Co. have pulled DVD drives out of mid-range to more expensive computers, such as HP’s Pavilion dm3z, which starts at $550, all the way up to the $1,700-and-up HP Envy and Dell’s $1,500-and-up Adamo.

Downloading ability has improved dramatically, and often software is delivered across a network, “so there’s no need for an optical drive,” said technology analyst Rob Enderle. Students are more likely to eMail or use peer-to-peer setups to share files and other items, he said, further reducing the need for optical drives.

Users might want to think twice, however, if they are hooked on transferring CDs into MP3s–or if they spend a lot of time watching DVDs on their computer screen and don’t want to squint at an iPod screen or get a separate portable video player.

• Good enough is plenty.

It might sound impressive when a PC sales pitch mentions multicore processors, state-of-the-art graphics chips, six or eight gigabytes of memory, and hard drives with a terabyte–1,000 gigabytes–of storage. But another thing netbooks have shown is that with a few exceptions–such as professional-grade video editing, and maybe hardcore video-game playing–having lots of PC power is overkill.