Forrest M. Mims III is the Country Scientist columnist for MAKE. If his name sounds familiar it Could be from the many books he wrote for Radio Shack, including one of my favorites, Getting Started in Electronics. His computer street credit goes way back – he was a co-founder of MITS, Inc. and wrote the first Altair 8800 user's guide.
The story begins at Out of Town News in Cambridge's Harvard Square on a snowy December afternoon in 1974. Allen visited the newsstand each month to check out the latest issues of Radio-Electronics, Popular Science, and similar magazines. When he saw the January 1975 issue of Popular Electronics, it stopped him in his tracks. Emblazoned on the cover was a photograph of the Altair 8800 microcomputer. The blurb over the photo read:
World's First Minicomputer Kit
to Rival Commercial Models…
"ALTAIR 8800" SAVE OVER $(removed)
Allen opened the magazine and found complete construction plans for the Altair 8800, which was available as a kit ($(removed)) or fully assembled ($(removed)). He soon noticed that the core of the Altair was Intel's powerful new 8080 microprocessor, the successor to the 8008. He quickly paid 75 cents for the magazine and hurriedly strode almost a mile to Harvard's Currier House, where sophomore Bill Gates resided. Gates shared Allen's enthusiasm for the Altair. Both men had become expert assembly language programmers during high school, and they decided to contact Altair developer Ed Roberts, who headed MITS, Inc. Their plan was simple: offer Roberts a version of the popular BASIC language that would run on the Altair.
After eight grueling weeks of programming, Allen flew to Albuquerque with a paper tape punched with their new BASIC. The code ran fine when simulated on a PDP-10 minicomputer at Harvard, but would it work with an Altair? While Roberts watched, Allen carefully entered into the Altair's front panel toggle switches the code he had written on the airplane to enable the Altair to load the BASIC from the Teletype terminal connected to the computer. The paper tape reader then loaded the BASIC into the Altair's memory. When Allen typed "PRINT 2+2", the Teletype immediately printed "4."
Roberts was amazed. So was Allen, though he didn't let on. Soon Roberts hired Allen, and later that year Gates joined him in Albuquerque. There, Allen and Gates formed a partnership that they initially called Micro-Soft.
And in case you missed it, here is Rob Beschizza's excellent interview with Paul Allen.