MOUNTAIN VIEW — Silicon Valley saw a revival on Saturday highlighted by 40-year-old circuit boards, punch-card readers and IBM and Macintosh machines the size of commercial microwave ovens.

For the first time since 2007, the Vintage Computer Festival West rose again. And it continues Sunday at the Computer History Museum in Mountain View.

With new operators in the Vintage Computer Federation (with conveniently identical initials) the festival was attended by hundreds of lifelong tinkerers and computer enthusiasts who wanted get a look at dozens of old machines –analog, digital and everything in between.

For many, getting a hands-on look — you’re allowed to touch and interact with most of the exhibits — at decades of computing history was a rare opportunity to reflect on how we went from machines the size of a small car to the pocket technology that has become standard issue in everyday life.

“You get to see where the technology of today came from,” said Rebecca Bettencourt, a 29-year-old San Francisco resident.

As Bettencourt looked at an IBM 5100 personal computer built in 1975, she added, “How they did this with the technology of their day is amazing. Now a smartphone has a million times the processing power of this entire floor.”

That floor, an upstairs exhibition hall at the museum, was packed with over 30 displays by exhibitors who traveled from as far away as Europe to show their wares.

The showpiece of the festival is an Apple I believed to be the earliest known model to still exist. The engineering prototype was hand-assembled by Apple cofounder Steve Wozniak.

The machine is being auctioned off to support the Leukemia and Lymphoma Society of Arizona at charitybuzz.com. As of Saturday afternoon, it had fetched a high bid of $270,000. Bids will be taken through Aug. 25.

Generations of computers were exhibited throughout the hall, from the Commodore 64 and Amiga lines to the hobbyist homebrew systems that were at the heart of the personal computing revolution that began in the 1970s.

To the organizers, it’s more than an exhibition. It’s a slice of the history that made Silicon Valley a household name around the world.

“More than half the stuff, it started here,” said Erik Klein, a San Jose resident who produced the weekend’s festival. “There’s so much local talent.”

Evan Koblentz, president of the Vintage Computer Federation, said the charm of the festival is akin to an antique car show — but “you get to drive everything.”

Kids are admitted for free, and on Saturday they could be seen playing old video games that are the precursors to the platformers and first-person shooters that litter the modern gaming landscape. All were run by 20-year-old computer systems.

One of the more unique displays was a “solid state” digital Monopoly game that Sunnyvale resident Stephen Casner first showcased at the Personal Computing Festival in Anaheim in 1978. He has tinkered and added to it in the decades since, including the telescoping tabletop casing and laminating the game board layout, which he obtained directly from Parker Brothers nearly 40 years ago.

Lifting the board from its base exposes the custom architecture and circuits that would have been a staple of what technology looked like in 1980s cinema.

“I had to solder all the chips myself,” Casner said.

All in part so that Casner could host Monopoly sessions without having to worry about keeping track of fake paper money or who gets to be the race car.

In other parts of the hall, some exhibits were the equivalent of walking into a time machine.

Tim Robinson, a native of Great Britain who now lives in Boulder Creek, cherished the revival of the festival because he was able to dust off a completely mechanical differential analyzer constructed with the British equivalent of an erector set.

Entirely analog, the system solves calculus equations in a matter that evokes images of the famed Turing machines used in World War II code-breaking.

“I needed a place to show it off,” Robinson said. “With this festival, you can’t really appreciate how computing changed until you see all this. Just looking at technology 15 years ago, you see how primitive it is compared to now. This is living history.”