Why Did OSI Fail?

• Technically, the OSI protocols were often criticised for their complexity and lack of "elegance". In fact, the protocols were known to be quite difficult to implement. This alone is not a sufficient reason for their failure.
   
  
• The TCP/IP protocol suite was supplied at no cost with BSD Unix, the operating system of choice in academia and research throughout the 1980s. By the end of the decade it was widely used.
   
  
• The OSI protocols suffered from a "specify first, implement later" design philosophy. At a time when the designers were not really sure of the best way to do things, this led to long delays before any implementation could be undertaken. Classically, the same problems have caused the failure of many large "Information Systems", and for similar reasons.
   
  
• The Internet protocols were developed using an "engineering" approach: "broad consensus and running code". Implementation experience continually fed back into design.
   
  
• etc...