Temperatures hit the 100s, desert dust hung in the air and a brush fire flickered a dozen miles away but 185,000 fans kept rocking as a giant music and computer festival swung into its second day today.

Music at the $12.5 million US Festival, promoted by Apple II computer designer Steve Wozniak, received generally good reviews. But concert-goers complained about the heat, the availability of food, and dust so thick that several security guards wore surgical masks and asthmatics flooded medical tents.

The three-day festival was billed as the "rock event of the century," by Unuson Corp., the staff of 30 assembled a year ago by Wozniak to turn his vision of a major music event into reality.

In the spirit of international unity, fans who paid $37.50 for weekend tickets listened to bands whose performances were to be beamed by satellite to the Soviet Union from the 57-acre natural amphitheater in Glen Helen Regional Park.

Today's 12-hour program on the world's largest portable stage included the Kinks, Pat Benatar, Tom Petty and the Heartbreakers, the Cars and Santana, the only band at the festival that also performed at the legendary 1969 Woodstock.

More than 1,000 security officers rode herd at the site. A half-dozen arrests were reported, said Sheriff's Sgt. Larry Stimach. Nevertheless, "I'm really shocked that these kids are so well behaved," Capt. Joe Karr said. "You couldn't have put this on in the '60s. It's just amazing."

The dust and heat accounted for most of the medical problems, with more than 500 people treated for ailments ranging from heat exhaustion to asthma, said Dean Grose, head of the medical team.

"We've averaged about 4 1/2 cases of asthma an hour," Grose said.