the emergence of venture capital on Sand Hill Road, beginning with Kleiner Perkins and Sequoia Capital in 1972; the availability of venture capital exploded after the successful $1.3 billion IPO of Apple Computer in December 1980. Since the 1980s, Silicon Valley has been home to the largest concentration of venture capital firms in the world. In 1971, Don Hoefler traced the origins of Silicon Valley firms, including via investments from Fairchild's eight co-founders. The key investors in Kleiner Perkins and Sequoia Capital were from the same group, directly leading to Tech Crunch 2014 estimate of 92 public firms of 130 related listed firms then worth over US$2.1 trillion with over 2,000 firms traced back to them. Rise of computer culture The Homebrew Computer Club was an informal group of electronic enthusiasts and technically minded hobbyists who gathered to trade parts, circuits, and information pertaining to DIY construction of computing devices. It was started by Gordon French and Fred Moore who met at the Community Computer Center in Menlo Park. They both were interested in maintaining a regular, open forum for people to get together to work on making computers more accessible to everyone. The first meeting was held as of March 1975 at French's garage in Menlo Park, San Mateo County, California; which was on occasion of the arrival of the MITS Altair microcomputer, the first unit sent to the area for review by People's Computer Company. Steve Wozniak and Steve Jobs credit that first meeting with inspiring them to design the original Apple I and (successor) Apple II computers. As a result, the first preview of the Apple I was given at the Homebrew Computer Club. Subsequent meetings were held at an auditorium at the Stanford Linear Accelerator Center. Advent of software Although semiconductors are still a major component of the area's economy, Silicon Valley has been most famous in recent years for innovations in software and Internet services. Silicon Valley has significantly influenced computer operating systems, software, and user interfaces. Using money from NASA, the US Air Force, and ARPA, Douglas Engelbart invented the mouse and hypertext-based collaboration tools in the mid-1960s and 1970s while at Stanford Research Institute (now SRI International), first publicly demonstrated in 1968 in what is now known as The Mother of All Demos. Engelbart's Augmentation Research Center at SRI was also involved in launching the ARPANET (precursor to the Internet) and starting the