Fundamentals of Quantitative Design and Analysis - Computer Architecture: A Quantitative Approach - page 5

as its tools. It is this style and approach to computer design that is reflected in this text. The
purpose of this chapter is to lay the quantitative foundation on which the following chapters
and appendices are based.
This topic was writen not only to explain this design style but also to stimulate you to con-
tribute to this progress. We believe this approach will work for explicitly parallel computers
of the future just as it worked for the implicitly parallel computers of the past.
1.2 Classes of Computers
These changes have set the stage for a dramatic change in how we view computing, comput-
ing applications, and the computer markets in this new century. Not since the creation of the
personal computer have we seen such dramatic changes in the way computers appear and in
how they are used. These changes in computer use have led to five different computing mar-
kets, each characterized by different applications, requirements, and computing technologies.
Figure 1.2 summarizes these mainstream classes of computing environments and their import-
ant characteristics.
FIGURE 1.2 A summary of the five mainstream computing classes and their system
characteristics . Sales in 2010 included about 1.8 billion PMDs (90% cell phones), 350 million
desktop PCs, and 20 million servers. The total number of embedded processors sold was
nearly 19 billion. In total, 6.1 billion ARM-technology based chips were shipped in 2010. Note
the wide range in system price for servers and embedded systems, which go from USB keys
to network routers. For servers, this range arises from the need for very large-scale multipro-
cessor systems for high-end transaction processing.
Personal Mobile Device (PMD)
Personal mobile device ( PMD ) is the term we apply to a collection of wireless devices with mul-
timedia user interfaces such as cell phones, tablet computers, and so on. Cost is a prime con-
cern given the consumer price for the whole product is a few hundred dollars. Although the
emphasis on energy eiciency is frequently driven by the use of bateries, the need to use
less expensive packaging—plastic versus ceramic—and the absence of a fan for cooling also
limit total power consumption. We examine the issue of energy and power in more detail in