Biology teacher Ed Chapman says a science maxim aptly describes the first year of an ambitious program in Henrico County, Va., to equip the district's high school students with laptop computers: "The more complex something is, the more likely it is that a small thing will upset it."

As the 2002-2003 school year was getting under way, Henrico school officials were confident last year's problems have been solved and the groundbreaking technology initiative will run more smoothly, even as it is expanded to the county's middle schools.

In one of the largest and highest profile initiatives of its kind, Henrico is paying $18.5 million over four years to lease iBook laptops from Apple Computer Inc. Computers were issued to about 11,000 high school students last year. About 23,000 iBooks will be deployed in the new school year.

"One of our most important lessons from the first year is making sure teachers have reliable access to the material," said Superintendent Mark Edwards. "We have had some of the top experts on wireless networks coming in and analyzing our preparedness for fall. We expect to have greatly enhanced network reliability."

Technical glitches were not the only problem in the program's first year. Some students were disciplined for downloading pornography and others for attempting to hack into the school's computer system to change grades.

Mike Smith, technology director for the Henrico schools, said a better internet filter will be used this year to prevent students from accessing inappropriate material. He said the filter is 95 percent to 98 percent effective.

"The porn industry wants to get to children," Smith said. "As long as that's the case, you're never going to be able to block 100 percent of it."

Security enhancements also will make it virtually impossible for students to use the wireless iBooks to hack into the school system's wired network, Smith said.

Despite such initial problems, the Henrico program has been a model for others. Maine has signed a deal with Apple to provide laptop computers to every seventh- and eighth-grader, and Roanoke County schools are planning a pilot program to provide laptops to some middle and high school students. Officials from both places visited Henrico in hopes of learning from its problems and successes.

Edwards emphasized that more than 99 percent of Henrico's high school students used their iBooks responsibly. Students are required to sign an agreement to use the computers appropriately.

Alina Karabaich, a sophomore at Mills Godwin High School, said she did not witness much misuse of the iBooks last year. Some students played games on the computers during study hall early in the year, she said, but school officials eliminated the games because they were taking up too much bandwidth.

Karabaich, 15, said she used her iBook for note-taking and to help design a web page on the Holocaust for a history class, but that was about it. Her father, Tony Karabaich, said some teachers seemed confused and ill-prepared for the initiative.