To Grasp the Cloud—Fundamental Concepts - Deploying and Managing a Cloud Infrastructure - page 28

This chapter covers some of the fundamentals of Cloud com-
puting. Virtualization is at the core of Cloud technology and
will be discussed at length though this chapter.
The True Nature of the Cloud
There are some distinct characteristics that define the modern cloud. The following sec-
tions provide an overview of some of these characteristics, which are covered in detail in
later sections.
History and Background
The cloud is not a new concept; in fact, it has been around since people starting using com-
puters. Therefore, we often refer to the modern version of cloud computing as “the second
birth of the cloud.” In their first life, they were known as mainframes, computers that occu-
pied enormous spaces. They were stuffed in large rooms akin to modern server rooms and
had multi-access capabilities because they were expensive and individual users could not
afford them. Therefore, big businesses and educational entities usually had a single main-
frame to which multiple users could connect. Features that we take for granted today were
not present in those bulky computers, but they did enable multiple users to connect to them
and run compute jobs (literal compute jobs like math computations, not the type of compute
jobs we run in today's servers). This was the first wave of cloud computing, but it stemmed
from limitations in technology in the late '50s and early '60s, not any “need” for huge com-
puters. This limitation vanished with the advent of PCs, which spelled the end of the first
wave of the cloud. The following photo shows an early IBM mainframe.