2 Cloud Computing
into two primary areas, hardware and software. We will look ﬁrst at the
1.2 Hardware Evolution
Our lives today would be different, and probably difﬁcult, without the ben-
eﬁts of modern computers. Computerization has permeated nearly every
facet of our personal and professional lives. Computer evolution has been
both rapid and fascinating. The ﬁrst step along the evolutionary path of
computers occurred in 1930, when binary arithmetic was developed and
became the foundation of computer processing technology, terminology,
and programming languages. Calculating devices date back to at least as
early as 1642, when a device that could mechanically add numbers was
invented. Adding devices evolved from the abacus. It was a signiﬁcant mile-
stone in the history of computers. In 1939, the Berry brothers invented an
electronic computer capable of operating digitally. Computations were per-
formed using vacuum-tube technology.
In 1941, the introduction of Konrad Zuse’s Z3 at the German Labora-
tory for Aviation in Berlin was one of the most signiﬁcant events in the evo-
lution of computers because this machine supported both ﬂoating-point
and binary arithmetic. Because it was a “Turing-complete” device,
it is con-
sidered to be the very ﬁrst computer that was fully operational. A program-
ming language is considered Turing-complete if it falls into the same
computational class as a Turing machine, meaning that it can perform any
calculation a universal Turing machine can perform. This is especially sig-
niﬁcant because, under the Church-Turing thesis,
a Turing machine is the
embodiment of the intuitive notion of an algorithm. Over the course of the
next two years, computer prototypes were built to decode secret German
messages by the U.S. Army.
1. Paul Wallis, “A Brief History of Cloud Computing: Is the Cloud There Yet? A Look at the
Cloud’s Forerunners and the Problems They Encountered,” http://soa.sys-con.com/node/
581838, 22 Aug 2008, retrieved 7 Jan 2009.
2. According to the online encyclopedia Wikipedia, “A computational system that can com-
pute every Turing-computable function is called Turing-complete (or Turing-powerful).
Alternatively, such a system is one that can simulate a universal Turing machine.”
http://en.wikipedia.org/wiki/Turing_complete, retrieved 17 Mar 2009.
3. http://esolangs.org/wiki/Church-Turing_thesis, retrieved 10 Jan 2009.
Chap1.fm Page 2 Friday, May 22, 2009 11:24 AM