What is an API? And why do I care? Take 1 - ENIAC to the first Mac

The Google Directions API post got many of my non IT friends curious to understand what exactly APIs are and why they are important. Some also suggested a quick post and adding a Tag to distinguish such fundamental posts, and so I will use a tag for these and oh well, call it Fundamentals

APIs or Application Programming Interfaces are a developer's instruction manual to using a piece of functionality exposed by a desktop software or web service programatically. In laymen terms, they define how to make a request to a software/service and what response to expect from it. APIs have a fairly long history in the world of computers and lets go back in time to discover how they came into existence. In the olden ages of computers, these multi-story devices (one of the first call ENIAC on your right) were primarily meant for the purpose of research, security or for giant institutions and available only to a rare few who had millions of dollars to spare. Several years later, some great companies like Apple, IBM and Microsoft and bright minds like Steve Jobs and Bill Gates came with the concept of personal computers and operating systems with the vision of taking computing to the household. That was in 1980's, some 30+ years ago!

It started with funny looking machines (and Ads :-)) and command line OS and soon GUIs (Graphical User Interfaces) started showing up. To your left is Steve Jobs presenting the first Mac in 1984!

These bright and cool guys (aka geeks) knew that they could not develop every piece of functionality on their own and why should they? For instance, on the software side they would focus on some basic (calculator), some fun (Solitaire) and some core business (Office) things and leave the rest to other third party developers.   They would create an ecosystem in which these things, called apps, applications or software would get created. And this ecosystem was to be largely driven by APIs. And guess what, even 30 years later it continues to be driven by APIs. These must be pretty important.  How they drive your PCs and Macs - we'll talk more in the Take 2