Allen and Gates formed Microsoft in 1975 in Albuquerque, New Mexico, and began marketing a BASIC programming language interpreter, with their first employee being high school friend and collaborator Ric Weiland.
Allen came up with the name of "Micro-Soft", a combination of "microcomputer" and "software".

Microsoft committed to delivering a disk operating system (DOS) to IBM for the original IBM PC in 1980, although they had not yet developed one, and Allen spearheaded a deal for Microsoft to purchase QDOS (Quick and Dirty Operating System) written by Tim Paterson who was employed at Seattle Computer Products.
As a result of this transaction, Microsoft secured a contract to supply the DOS that ran on IBM's PC line and led to Allen's and Gates' wealth and success.

The relationship between Allen and Gates became strained as they argued even over small things.
Allen effectively left Microsoft in 1982 after being diagnosed with Hodgkin's lymphoma, though he remained on the board of directors as vice chairman.
Gates reportedly asked Allen to give him some of his shares to compensate for the higher amount of work that Gates was doing.
According to Allen,  Gates said that he "did almost everything on BASIC" and the company should be split 60–40 in his favor.
Allen agreed to this arrangement, which Gates later renegotiated to 64–36.
In 1983, Gates tried to buy Allen out at $5 per share, but Allen refused and left the company with his shares intact; this made him a billionaire when Microsoft went public.
Gates later repaired his relationship with Allen, and the two men donated $2.2 million to their childhood school Lakeside in 1986.
They remained friends for the rest of Allen's life.

Allen resigned from his position on the Microsoft board of directors on November 9, 2000, but he remained as a senior strategy advisor to the company's executives.
In January 2014, he still held 100 million shares of Microsoft.
Allen and Gates formed Microsoft in 1975 in Albuquerque, New Mexico, and began marketing a BASIC programming language interpreter, with their first employee being high school friend and collaborator Ric Weiland. Allen came up with the name of "Micro-Soft", a combination of "microcomputer" and "software".
Microsoft committed to delivering a disk operating system (DOS) to IBM for the original IBM PC in 1980, although they had not yet developed one, and Allen spearheaded a deal for Microsoft to purchase QDOS (Quick and Dirty Operating System) written by Tim Paterson who was employed at Seattle Computer Products. As a result of this transaction, Microsoft secured a contract to supply the DOS that ran on IBM's PC line and led to Allen's and Gates' wealth and success.
The relationship between Allen and Gates became strained as they argued even over small things. Allen effectively left Microsoft in 1982 after being diagnosed with Hodgkin's lymphoma, though he remained on the board of directors as vice chairman. Gates reportedly asked Allen to give him some of his shares to compensate for the higher amount of work that Gates was doing. According to Allen,  Gates said that he "did almost everything on BASIC" and the company should be split 60–40 in his favor. Allen agreed to this arrangement, which Gates later renegotiated to 64–36. In 1983, Gates tried to buy Allen out at $5 per share, but Allen refused and left the company with his shares intact; this made him a billionaire when Microsoft went public. Gates later repaired his relationship with Allen, and the two men donated $2.2 million to their childhood school Lakeside in 1986. They remained friends for the rest of Allen's life.
Allen resigned from his position on the Microsoft board of directors on November 9, 2000, but he remained as a senior strategy advisor to the company's executives. In January 2014, he still held 100 million shares of Microsoft.
Paul Allen