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Formal Parameter FIGURE 113. Form, HTML (as displayed on screen) Formal Parameter formal parameter a name used within a function or subroutine for a value that will be passed to it from the calling program. Contrast ACTUAL PARAMETER. Format format any method of arranging information that is to be stored or dis- played. The word [...]

Firefox In Windows, a similar function is available by choosing Search on the start menu. 3. a Windows command that finds all lines in a text file that contain a particular character string; a less powerful version of the UNIX grep command. For example, this command will display all the lines in myfile.txt that contain [...]

F F keys see FUNCTION KEYS. F-Ratio f-ratio the focal length of a lens divided by the clear aperture (diameter) through which light enters. The adjustment for f-ratio is called the F-STOP. The f-ratio determines the brightness of the image formed by the lens; lower f-ratios produce brighter images. Thus, a camera with an f/1.8 [...]

Ellipsis FIGURE 93. Eliza in action ellipsis typographic convention of using three dots (. . . ) to indicate the trailing off of a thought. In Windows, the ellipsis is typed by holding down Alt while keying 133 on the numeric keypad. Macintosh users can type an ellipsis by holding down Option and typing : [...]

E e (in mathematics) an important number whose value is approximately 2.71828. The reason e is important is that the function ex is its own deriv- ative. In many programming languages, the function exp(x) computes ex. If y = ex, then x is the natural logarithm of y. E see EXPONENTIAL NOTATION. e- prefix meaning [...]

Default Directory default directory see CURRENT DIRECTORY. default drive see CURRENT DRIVE. Default LOgic default logic (defeasible logic) a formal system of reasoning in which some facts or rules have priority over others. For example, statements about ostriches might have priority over statements about birds because an ostrich is a specific kind of bird. It [...]

Arc 1. part of a circle. 2. a data compression program for the IBM PC formerly produced by System Enhancement Associates in the mid-1980s, a precursor of ZIP. See ZIP FILE. arccos, arc cosine the inverse of the trigonometric cosine function. If x = cos y, then y = arccos x. Many computer languages provide the arc tan- gent function but not the arc cosine function. [...]

abort abort to cancel an action or command. Abort, Retry, Fail? an error message displayed by DOS and similar oper- ating systems when a disk is unreadable or some other input or output operation is physically impossible. An earlier version said, “Abort, Retry, Ignore?” abs the function that calculates absolute value in many programming lan- guages and on [...]

Micro kernels This method structures the operating system by removing all non-essential components from the kernel and implementing as system and user level programs. The result is a smaller kernel. Micro kernels typically provide minimum process and memory management in addition to a communication facility. The main function of the micro kernel is to provide [...]

As shown in Figure 3.3, there are four events that cause execution of a piece of code in the kernel. These events are: interrupt, trap, system call, and signal. In case of all of these events, some kernel code is executed to service the corresponding event. Figure 3.3  Entry points into the operating system kernel [...]