The Origins and Future of Distributed Computing and Clouds - The Practice of Cloud System Administration - page 448

• The second web era: The resurgence from 2003 to 2010
• The cloud computing era: Where we are today
Each period had different needs that drove the technology decisions of the day, pushing
evolution forward step by step. These needs changed over time due to the ebb and flow of
economicprosperity,themarchoftechnologicalimprovement,andincreasingexpectations
of reliability and speed. This appendix provides our interpretation of how it happened.
B.1 The Pre-Web Era (1985-1994)
Computing was different prior to the web. Reliability and scale were important but not in
the same waythey are today.The Internet wasusedonlybyasmall groupoftechnologists,
and most people were unaware of its existence.
Availability Requirements
For most businesses, their internal operations were reliant on computers, but outages were
largely invisible to external customers. The exceptions were companies whose customers
includedalargesegmentofthepopulationandaccessedtheservicesfromoutsidethebusi-
ness premises—for example, telephone companies whose customers were making phone
calls and banks that provided ATMs. Customers expect those services to be available on a
24 × 7 basis.
In this era most large businesses were already heavily reliant on computers for the bulk
of their work. Some employees had remote access from home, over a telephony-based mo-
dem, sometimes with a dumb terminal, sometimes with a PC or Mac.
Mostbusinessescouldscheduleoutagesformaintenance—bylookingatproductrelease
schedules and avoiding the end-of-quarter period. The customers of the computer systems
were internal to the company, and there were easy, defined ways of contacting them to
schedule downtime.
The Internet was largely text-based, with email, Internet news, bulletin boards, and file
transfer programs. Outages of an Internet service might cause a backlog of email or news,
butwentlargelyunnoticedbymostpeople.Formostpeople,Internetaccesswasaperk,but
it was not business-critical. Some companies offered anonymous-ftp drop-boxes for third
parties, such as customers needing support. Little other commercial business was carried
out over the Internet. It was far from clear in the early days whether it was a potential ac-
ceptable use policy violation to use the Internet for commercial purposes.
During this era, 24 × 7 operation was important for some internal corporate systems,
but not for Internet services. Maintenance outages of internal systems could be scheduled,
because the user population was known and could be easily informed.