Texas Instruments TI-89 Tip List page 459

command
A routine which is neither a function nor a program. All commands are built-in. The arguments for a
command are not passed in parentheses, unlike the arguments for programs and functions. See also
program and function.
command line See entry line
complex
Applies to an expression or number which has an imaginary component. For example, 3 + 2i is a
i = −1
complex number, where . Complex does not mean 'complicated'.
conditional operator
An operator such as >, < or =, which is applied to two expressions. A conditional expression evaluates
to true or false.
constraint
An expression that limits the range of operation of expression evaluation. Constraints are applied with
the 'with' operator |. For example, in the expression a+b|a=2, the constraint is a=2. Constraints may be
composed with various combinations of Boolean operators.
contrast
Refers to the LCD screen contrast, that is, the level of darkness. The contrast changes with battery
voltage. New batteries result in a dark screen, but the contrast decreases as the batteries age. The
contrast is adjusted by pressing the [DIAMOND] key simultaneously with the [+] and [-] keys, as
indicated by the green legend on the keyboard. If the contrast is set too light, it may appear that the
calculator is off when it is actually on. Oddly, the contrast can be set on the VTI emulator, and must be
changed when the emulator is reset.
copy See cut, copy, paste
crash
An error condition in which the calculator will not respond to keystrokes, perform calculations, or turn
on or off. Also called freeze-up, lockup or black-bar. The 'black-bar' term comes from the symptom of a
thick black bar appearing at the top of the LCD display when a crash occurs. Crashes are usually
caused by ASM games and shells. Crashes from normal calculator operation or TI Basic programs are
extremely rare. The display often shows the error message Address Error after a crash. Instructions for
recovering from a crash are given in the User's Guides.
current
Adjective which describes a default calculator object. For example, the 'current folder' is the folder in
which variables are stored, if a different folder is not specified. The 'current matrix' is the matrix that is
currently in the Data/Matrix editor.
cursor
The display symbol which indicates the position at which text appears when keys are pressed. The
cursor symbol is shown as a flashing vertical bar, unless insert mode is active, in which case the
cursor is shown as a flashing solid rectangle.
cursor keys
The keys which move the cursor in the display. Also called the 'arrow keys'. In this document I refer to
these keys as [UP], [DOWN], [LEFT] and [RIGHT]. The TI-89 has dedicated cursor keys, the TI-92
Plus has a blue cursor pad.
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