Chapter 4 - DSpace at Waseda University

Chapter 1
functions or equipped with its own OS. For these innovations, people prefer to use a
smartphones, and the role of smartphone is increasing, substituting for computers.
In terms of hardware, there is the Moore's Law, which is one of the most important laws in
history of computer hardware. Moore's law describes a long-term trend in the history of
computing hardware, in which the number of transistors that can be placed inexpensively on
an integrated circuit double approximately every two years. Although the Moore's law has
satisfied in the past several decades, these days it seems to be at a breaking point. Over the
past year the efficiency of semiconductor manufacturing has greatly increased, and the
internal structure of semiconductor has also become much integrated. Therefore there is only
some possibility to make it more integrated. On the other hand, software has a lot of
development potential. Even the same hardware, a developer can set up different kinds of
software in it. Moreover, even the same software, depends on the developer, the performance
[4] and occurred errors are different. Therefore, the software is becoming important as time
goes by.
In general, software consists of OS, middleware and application. Because each group has
different features and functions, every group is much important as itself. However, OS is
remarkably important since it controls and manages all the hardware on embedded systems to
keep running applications without any problems. Therefore, it is the fundamental of computer
science. Many OSes such as Unix, Linux and Windows are currently used in personal
computers. And, there are many OSes for embedded systems, too.
For example, there is Android [53] from Google, iOS4 [54] from Apple, embedded
Windows from Microsoft and embedded Linux. Especially, embedded Linux has been widely
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