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Unformatted text preview: CSE115 Course Notes 2009 C. Alphonce and A. Decker Page 2 Lesson 1: Preliminaries This text introduces you to software development, in particular computer programming. Understanding how to write computer programs, and how computer programs are executed by a computer, offers an introduction to the fields of computer science and computer engineering. The fields of computer science and computer engineering are very broad, offering many different areas of specialization. Whatever your interests are, whether they lie primarily in hardware or software, or theory or applications, computer science and computer engineering have something to offer. Hardware refers to the physical computer and its components. At the core of a modern digital computer is a central processing unit (CPU) and random access memory (RAM). The CPU is responsible for carrying out computations specified by a computer program. The RAM stores both the computer program and the data which the computer program is processing. RAM is volatile memory, meaning that it stores information only so long as it has power. If the computer is turned off, everything stored in RAM is lost. For this reason computers have long-term storage, often in the form of a hard drive. A hard drive stores information in a way which is not dependent on a continuous power source. Programs and data are loaded into RAM from a hard drive when the computer is first turned on, or when an application is launched. Software refers to the programs which run on a computer. A very important program is the operating system, which provides basic services to other programs running on the computer. Popular operating systems include Windows, Linux and OS-X. An operating system allows a computers hardware to multitask: keep several programs in RAM at once, and let each one process for a short period of time before switching to another program, giving the impression that multiple programs are running all at the same time (such as your operating system, a web browser, a word processor and a chat client). Other programs are started only when the user of the computer runs them. Examples of such programs include a web browser, an e-mail client and a photo viewer. The theory of computing deals with issues such as the limits of computation (there are problems which simply cannot be solved using a computer) and the efficiency of computations....
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- Fall '08
- Computer Programming