Dan Rose, chairman of Coatue Ventures and Coatue Growth, posted a thread on Twitter the other day, 280 characters or less at a time, in which he chronicled how it came about that AWS infrastructure is built on Linux.\nRose was at Amazon from 1999 to 2006, where he managed retail divisions and helped incubate the Kindle reader before moving to Facebook. So he was at Amazon in 2000 when the internet bubble popped,and one high-flying dot-com after another was shriveling up and dying, having burned through ridiculous amounts of capital on luxurious offices while often having nothing by way of a product to show for it.\nRose said Amazon\u2019s biggest expense was the data center outfitted with expensive Sun servers. Amazon\u2019s motto was \u201cget big fast,\u201d and site stability was critical. Every second of downtime meant lost sales, and Sun was the gold standard for internet servers back then. I can recall them having a significant software business led by a VP named Eric Schmidt.\nSun\u2019s proprietary stack was \u201cexpensive & sticky,\u201d as Rose put it, and it was designed that way. Back then the Unix market was Sun, HP, IBM, and SGI, and they all had variants of Unix operating systems that were designed to be less than portable.\nBut it is safe to say the early internet was built on Sun\u2014and not Solaris, either. Sun had a second OS, a BSD derivative called SunOS that had no GUI. (In the pre-DNS days while in college, I cut my teeth on SunOS 3.x and had to learn Unix command line. My first ISP out of college dropped you into a SunOS shell, and if you didn\u2019t know what to do staring at the % prompt you were lost.)\nAs startups died in 2000 and liquidated their data-center gear, brand-new Sun servers started appearing on eBay for 10 cents on the dollar. As a result, Sun sales took a big hit, which marked the beginning of the end for Sun.\nAmazon could have used that predicament to negotiate a better deal with Sun, Rose posted, but Jeff Bezos chose a more radical approach. Amazon\u2019s CTO Rick Dalzell pivoted the entire engineering organization to replace Sun with HP\/Linux. Today no one would blink at such a move, but in 2000 it was relatively daring. After all, Linux 1.0.0, the first production-ready version, had only been released in 1994.\n\u201cSix years later we were betting the company on it, a novel and risky approach at the time,\u201d said Rose. Product development ground to a halt during the transition. The company froze all new features for over a year as it faced a huge backlog, but nothing new could ship until they completed the shift to Linux.\nDuring this time period revenue slowed. The dot-bomb implosion was continuing, the economy was sliding into recession in 2001, and then 9\/11 happened. Amazon came within a few quarters of going bankrupt, Rose said.\n\u201cBut once we started the transition to Linux, there was no going back. All hands on deck refactoring our code base, replacing servers, preparing for the cutover. If it worked, infra costs would go down by 80%+. If it failed, the website would fall over and the company would die,\u201d he wrote.\nWhen it completed the transition, the site chugged on with no disruption. \u201cCapex was massively reduced overnight. And we suddenly had an infinitely scalable infrastructure,\u201d said Rose. \u201cThen something even more interesting happened. As a retailer we had always faced huge seasonality, with traffic and revenue surging every Nov\/Dec. Jeff started to think\u2014we have all this excess server capacity for 46 weeks\/year, why not rent it out to other companies?\u201d\nAround the same time, Bezos was also interested in decoupling internal dependencies so teams could build without being gated by other teams. The architectural changes required to enable this loosely coupled model became the API primitives for AWS. Bezos took an interesting view of things.\n\u201cHe framed the idea in the context of the electric grid. In 1900, a business had to build its own generator to open a shop. Why should a business in 2000 have to build its own data center?\u201d Rose wrote.\nHe acknowledged that cloud infrastructure would have emerged eventually even without AWS, but how much later and at what opportunity cost? With the availability of AWS infrastructure as a service, the cost of rolling out a startup was reduced dramatically, innovation exploded and the modern venture capital ecosystem was born, he said.