Mark Zbikowski

Mark "Zibo" Joseph Zbikowski (born March 21, 1956) is a former Microsoft Architect and an early computer hacker. He started working at the company only a few years after its inception, leading efforts in MS-DOS, OS/2, Cairo and Windows NT. In 2006, he was honored for 25 years of service with the company, the third employee to reach this milestone, after Bill Gates and Steve Ballmer. He retired the same year from Microsoft.

He was the designer of the MS-DOS executablefile format, and the headers of that file format start with his initials: the ASCII characters 'MZ' (0x4D, 0x5A).