The electronic computer is a relatively new invention which has already changed many facets of the way we live. Computer applications are likely to have an even bigger role in the shaping of society in the future. The aim of this portion of CmpE 150 is to give the student "literacy" on computers and data processing. We will cover the basic notions underlying computer hardware and software, and some of their major applications. We will try to get familiar with the computer industry. Issues related to the social impact of electronic computing will be discussed.

In the preparation of these texts, the book "Computers and Their Applications" (3rd ed.) by Charles S. Parker was used, among others. It is a nice book, and you are encouraged to buy an original copy if you can find it.

We understand "literacy" as a mastery of basic terminology about the issue at hand. In this particular case, our main aim will be to provide a list of definitions of key computing terms that the student may encounter in his/her daily life: in an office environment, in the newspaper, etc. Having thus stated our approach, we start our exposition with the most basic term of all:

A computer is an information processing device. Its function is to produce new items of information from old ones. The act of "putting" information "in" to the computer is called input. (The information put in in this manner is also called input, so you should be able to understand the difference from the context.) The act of creating new items of information from old ones is called processing. The items of information "put out" by the computer, and the act of making this happen are both called output. The "area" within the computer used to hold information during all these stages is called storage, or memory. Note that these definitions are very broad, in the sense that we do not specify anything about how all these acts are realized; in particular, we do not say that the device should consist of electronic circuits. In fact, a human being is also a computer, according to the definition above.

We now concentrate on the kinds of electronic computers which are the subject matter of this course. The part of the computer which directs all the above-mentioned acts and carries out the processing is called the central processing unit, or CPU. Parts of the computer which perform the input and output are called input devices and output devices, respectively. The keyboard on your PC (personal computer) is an input device. The monitor is an output device. Objects which can hold information in a machine-readable form so that it can be transferred to or from the computer are called input/output (I/O) media. Your diskettes are examples to this.

Data (a plural word which means "given things") is another name for information. If the computer is being used to hold and process information about the names and grades of a group of students taking a course, the students' names and numbers are data for this application. Sometimes, we provide lists of instructions about what to do on some data set as input to the computer. Such lists of instructions are called programs. Programs have to be written in a programming language which the computer has the means to interpret, so that the instructions can be carried out (executed) by the computer. Pascal is a programming language.

Basically, there are two types of memory in a computer. Main memory (primary memory) is located within the device. The information that is currently being processed resides in main memory. Other data can be held in secondary memory. Secondary memory may or may not be fixed within the computer. Your diskettes are secondary memory. Hard disks (located within relatively expensive computers) are also secondary memory. Main memory is volatile, that is, it loses its contents when the computer is turned off. Secondary memory is not volatile. Generally, secondary memory has a bigger capacity and is slower (i.e., it takes longer to put/take a piece of information in/from it) than main memory.

The actual pieces of machinery ("things that you can touch") related to computers are called hardware. Computer programs (recall that they are just pieces of text) are called software.

Anybody who uses a computer is called a user. If you are a user who writes and "runs" (i.e. lets the computer execute) programs, you are a programmer.

The smallest and cheapest computers are called microcomputers or personal computers. As size and price go up, the names given to computers are: minicomputers, mainframes, and supercomputers. You will be preparing your programming projects on PC's. We do not have a supercomputer in our university, these are used for tasks which demand great computation speed and accuracy.

Computer science is the study of computers. Computer engineers are computer scientists who not only study but also build certain parts of new computer systems. In addition to its dictionary meaning, we use computing to mean "using a computer for a specific task."

Knowing about computers is important if you want to function successfully in today's world, no matter what your profession is. Computers are in the stock market. Computers are in the telephone exchange. Computers are in any commercial establishment you can think of. Using computer networks, you can access vast amounts of data in almost any subject without leaving your room. Some people use computers to steal lots of money from other people. Some day, we may have computers which can act and talk such that they are indistinguishable from human beings. All these are important things. That is why you are taking this course.