T

tagged file format

A file format in which data is tagged using standard headers that identify information type and length. See also Resource Interchange File Format (RIFF).

tape drive

A device that reads from and writes to a tape.

tape volume

A recording medium and its physical carrier.

tempo

The speed at which a Musical Instrument Digital Interface (MIDI) file is played. Tempo is measured in beats per minute (BPM); typical MIDI tempo is 120 BPM. See also Musical Instrument Digital Interface.

tension

To move the tape to the end-of-medium marker and back to the beginning-of-medium marker in one command.

termination handler

A mechanism by which a developer ensures that a block of termination code is executed. A termination handler consists of a guarded body of code and a termination block. See also guarded body of code.

thread

The basic entity to which the operating system allocates CPU time. A thread can execute any part of the application's code, including a part currently being executed by another thread. All threads of a process share the virtual address space, global variables, and operating system resources of the process. See also process.

thread affinity mask

A bit vector in which each bit represents the processors that a thread is allowed to run on.

thread local storage

A storage method in which an index can be used by multiple threads of the same process to store and retrieve a different value for each thread. See also thread.

threshold

For the joystick interface, the amount, in device units, that the stick coordinates must change before the application is notified of the movement. A high threshold reduces the number of joystick messages sent to an application, but it also reduces the sensitivity of the joystick.

time-out value

The interval, in milliseconds, measured by a timer.

timer

An internal routine that causes the system to send a WM_TIMER message whenever a specified interval elapses.

timer object

An interprocess synchronization object whose state is set to signaled when the specified due time arrives. See also due time, synchronization object.

time slice

A unit of processor time (in clock ticks) allocated to a thread. See also thread.

time stamp

A tag that enables a Musical Instrument Digital Interface (MIDI) sequencer to replay recorded MIDI data at the proper moment. See also Musical Instrument Digital Interface.

title bar

A window component that displays an application-defined line of text. Typically, the text identifies the application or indicates the purpose of the window.

TLS

See thread local storage.

TMSF time format

A time format used by Media Control Interface (MCI) to express time in tracks, minutes, seconds, and frames. The number of frames in a second depends on the type of device being used; compact disc audio devices use 75 frames per second. The TMSF time format is used primarily by compact disc audio devices. See also Media Control Interface (MCI).

token

See access token.

top-down DIB

A device-independent bitmap (DIB) whose origin lies at the top-left corner. See also bottom-up DIB.

top-level window

A window that has no parent window.

topic name

A string that identifies the type of data requested by a dynamic data exchange (DDE) client application.

topmost window

A window with the WS_EX_TOPMOST style. A topmost window overlaps all other non-topmost windows.

track

A sequence of sound on a compact disc – digital audio (CD-DA) disc. With a Musical Instrument Digital Interface (MIDI) file, information can be separated into tracks, defined by the creator of the file. MIDI file tracks can correspond to MIDI channels, or they can correspond to parts of a song (such as melody or chorus); a CD-DA track usually corresponds to a song. See also compact disc – digital audio.

transaction filter

A flag that prevents the Data Exchange Management Library (DDEML) from passing an unwanted type of transaction to an application's dynamic data exchange (DDE) callback function. See also dynamic data exchange (DDE).

transformation

An algorithm that alters ("transforms") the size, orientation, and shape of objects.

translation

A transformation that shifts an object farther from or closer to the coordinate-space origin.

tristimulus value

The amounts of the three primary color stimuli necessary to produce a color match by additive color mixing.

TrueType font

A font whose glyphs are stored as a collection of line and curve commands plus a collection of hints. Windows uses the line and curve commands to define the outline of the glyph's bitmap. Windows uses the hints to adjust the length of the lines and shapes of the curves. These hints and the respective adjustments are based on the amount of scaling used to reduce or increase the size of the bitmap. See also bitmap, font, glyph.

Trustee

In Windows NT security, a trustee is the user account, group account, or logon session to which an access-control entry (ACE) applies. Each ACE in an access-control list (ACL) applies to one trustee. See also access-control entry (ACE), access-control list (ACL).

try block

A guarded body of code in a try-except frame-based exception handler or try-finally termination handler. See also frame-based exception handler, guarded body of code, termination handler.