Two decades and a half ago today, Bill Gates unveiled Microsoft’s first operating systems. Even though it wasn’t for sale that year Bill Gates confidently promoted it in New York and claimed 90% of all IBM PCs would run on that operating system.

Immediately after making those claims Microsoft slipped on the release by more than a year and the final commercial product was available two years after Gates’ announcement.

Sales were modest as well - with plenty of competition from Apple and other brands.

However, 25 years down newer versions of the OS with the graphical user interface is indeed on more than 90% computers.