S

SACL: See system access control list.
sample: A discrete piece of waveform data represented by a single numerical value. Sampling is the process of converting analog data to digital data by taking samples of the analog waveform at regular intervals.
sampling rate: The rate at which a waveform audio driver performs audio-to-digital or digital-to-audio conversion. For compact disc – digital audio (CD-DA), the sampling rate is 44.1 kHz. See also compact disc – digital audio
Save As common dialog box: A common dialog box that displays a list of filenames matching any specified extensions, directories, or drives. By selecting one of the listed filenames, the user indicates what file an application should save. See also common dialog box.
scalable font: A TrueType font. See also TrueType font.
scaling: A transformation that alters the apparent size of an object.
scan code: A device-dependent value that identifies a physical key on the keyboard. Each key on a keyboard generates two unique scan codes--one when the user presses the key and the other when the user releases the key.
scan line: A single row of adjacent pixels on a video display. See also pixel.
scheduler: The component of the operating system that determines which of the competing threads receives the next slice of the processor's time. See also thread.
screen buffer: A two-dimensional array of character and color data for output in a console window. A screen buffer can be accessed for reading and writing whether it is active or inactive. Its character data can be either a Unicode™ or ANSI value. See also console window.
screen coordinates: Coordinates relative to the upper left corner of the screen.
scroll bar: An element of the Windows user interface that converts mouse or keyboard input into values that a window procedure can use to shift the contents of a window's client area either horizontally or vertically. See also window procedure.
scroll bar control: A predefined control window that belongs to the SCROLLBAR window class. See also window.
scroll box: A movable area in a scroll bar that indicates the position of the information currently displayed in the associated window. The position of the scroll box is relative to the total amount of information available for display. See also scroll bar.
scrolling: The process of shifting a data object in a window's client area in order to see parts of the object that extend beyond the border of the client area.
scrolling range: The minimum and maximum values that a scroll bar can report. See also scroll bar.
secant: A line drawn through two points on an ellipse. See also ellipse.
secret: A key value that the software publisher chooses and then typically encrypts within the software license. An LSAPI-compliant license must have a minimum of four secrets, each 4 bytes (32 bits) long. See also basic challenge protocol, License Service Application Programming Interface (LSAPI), MD4 Message-Digest Algorithm.
security descriptor: A structure and associated data that contains the security information for a securable object. A security descriptor identifies the object's owner and primary group. It can also contain a DACL that controls access to the object, and a SACL that controls the logging of attempts to access the object. See also absolute security descriptor, discretionary access-control list (DACL), self-relative security descriptor, system access-control list (SACL).
security domain: A collection of nodes in a security database that share a common set of user and group accounts.
security identifier (SID): A structure of variable length that uniquely identifies a user or group on all Windows NT® implementations.
seek: (1) With file input and output (I/O), to change the current position in the file. (The current position is the location where the next read or write operation will take place.)
(2) With a media device (such as a hard disk), to position the medium so a certain sector can be accessed. The seek operation involves a physical movement of the device, so the time it takes can often be perceived by the user.
selection field: The portion of a combo box that displays the currently selected item. Selecting an item in the list causes that item to appear in the selection field. In simple and drop-down combo boxes, the selection field is an edit control and can be used to enter input not in the list.
self-relative security descriptor: See security descriptor.
semaphore object: An interprocess synchronization object that maintains a count between zero and some maximum value. The object's state is set to signaled when its count is greater than zero, and nonsignaled when its count is zero. See also synchronization object.
sequence: See MIDI sequence.
sequencer: See MIDI sequencer.
service: An executable object that is installed in a registry database maintained by the Service Control Manager. The executable file associated with a service can be started at boot time by a boot program or by the system, or it can be started on demand by the Service Control Manager. The two types of service are Win32 service and driver service. See also driver service, Win32 service.
service control manager: A Windows NT system process that provides a unified and secure means of controlling Win32 and driver services. Each computer that is running Windows NT has a service control manager process that is started during system startup.
service name: A string that a server application responds to when a client attempts to establish a conversation with the server.
setmark: A special recorded element that contains no user data and is used to provide a segmentation scheme hierarchically superior to filemarks. Setmarks typically provide faster positioning on high-capacity tapes.
share mode: A condition that indicates whether a file is to be shared for reading, writing, both, or neither.
shared arena: The Windows 95 shared arena (or shared address space) is the memory in the address range between 2 GB and 3 GB. It contains components that must be mapped into the address space of every process, such as the 16-bit global heap, shared system DLLs, and file views of file mapping objects. The DPMI server also allocates memory in this address range.
shared memory: Memory that two or more processes can read from and write to. If the file-mapping object that references the shared memory has a name, the memory is referred to as "named shared memory."
sharepoint: A network resource that remote applications can address specifically and use across a network--for example, a printer or a shared directory. See also container.
shearing: A transformation that alters the apparent length and orientation of vertical or horizontal lines in an object.
shell: An application that enables users to group, start, and otherwise control other applications.
short filemark: A filemark that contains a short erase gap that cannot be overwritten unless the write operation is performed from the beginning of the partition or from an earlier long filemark.
show state: The collective qualities of a window at a given time (whether active or visible; minimized; maximized; or restored).
shut down: To stop all processes, flush all file-system buffers to disk, and bring the system to a condition in which it is safe to turn off the computer.
sibling window: A child window that has the same parent window as one or more other child windows.
SID: See security identifier (SID).
signaled: The state of an object used for synchronization in one of the wait functions. A signaled state can enable the wait function to return. See also nonsignaled, wait function.
signature: A 4-byte value that identifies an enhanced metafile. See also enhanced metafile.
simple combo box: A combo box in which the list box is visible at all times.
simple device: A media control interface (MCI) device that does not require a device element (data file) for playback. The MCI compact disc audio driver is an example of a simple device.
simple list: A list in a combo box that is always visible. Combo boxes with the CBS_SIMPLE style contain simple lists.
single-byte character set: A mapping of characters to their identifying numeric values, in which each value is one byte wide. The ANSI and original equipment manufacturer (OEM) character sets are single-byte character sets. See also character set, multibyte character set, Unicode.
single-selection list box: A list box in which only one item can be selected at a time.
sizing border A type of window border that enables the user to size the window by clicking and dragging the border.
SMPTE: See Society of Motion Picture and Television Engineers.
SMPTE division type: One of four SMPTE timing formats. SMPTE time is expressed in hours, minutes, seconds, and frames. The SMPTE division type specifies the frames-per-second value corresponding to a given SMPTE time. For example, a SMPTE time of one hour, 30 minutes, 24 seconds, and 15 frames is useful only if the frames-per-second value, or SMPTE division type, is known.
SMPTE offset: A Musical Instrument Digital Interface (MIDI) event that designates the SMPTE time at which playback of a MIDI file is to start. SMPTE offsets are used only with MIDI files using SMPTE division type.
SMPTE time: A standard representation of time developed for the video and film industries. SMPTE time is used with Musical Instrument Digital Interface (MIDI) audio because many people use MIDI to score films and video. SMPTE time is an absolute time format expressed in hours, minutes, seconds, and frames. Standard SMPTE division types are 24, 25, and 30 frames per second.
Society of Motion Picture and Television Engineers (SMPTE): An association of engineers involved in movie, television, and video production. SMPTE also refers to SMPTE time, the timing standard that this group adopted.
solid brush: A logical brush created from a bitmap that contains pixels of the same color. See also bitmap, logical brush, pixel.
source: A configuration registry key that specifies message-file names for replacement strings in events logged by an application, service, or group of applications. Sources are subkeys of logfile keys. See also key, logfile, subkey.
square-wave synthesizer: A synthesizer that produces sound by adding square waves of various frequencies. A square wave is a rectangular waveform.
standard cursors: The default cursors that the system automatically displays when users move windows or icons, resize windows, or wait. Standard cursors include an arrow, hourglass, crosshair, and I-beam. Standard cursors are also known as system cursors. See also cursor, icon, window.
standard icons: The default icons that the system displays in system message boxes. Standard icons include, among other bitmaps, a stop sign and a circled exclamation point. See also icon.
standard resource: A resource whose format is defined and recognized by Windows. Standard resources include icons, cursors, menus, dialog boxes, bitmaps, fonts, keyboard accelerator tables, message-table entries, string-table entries, and version data.
standard scroll bar: A scroll bar created as part of the nonclient area of an overlapped, pop-up, or child window. See also scroll bar.
standard VGA: A video adapter that supports a resolution of 640 by 480 pixels and 16 simultaneous colors. See also pixel.
static control: An element of the Windows user interface used to display text and graphics that require no response from the user. Static controls are typically used in dialog boxes.
stock brush: One of seven logical brushes maintained by the system. See also logical brush.
stock pen: A cosmetic pen created and maintained by the window manager. There are three kinds of stock pens: black, white, and invisible. See also cosmetic pen.
streaming: The process of transferring information from a storage device, such as a hard disk or CD-ROM, to a device driver.
string atom: An atom that identifies a character string in an atom table. See also atom, atom table.
string handle: A doubleword value, assigned by the operating system, that identifies a string passed between a dynamic data exchange (DDE) client and a DDE server. See also dynamic data exchange (DDE).
stroked path: A path that is outlined by using the pen that is currently selected into an application's device context. See also device context, path, pen.
structured exception handling: A mechanism for handling hardware- and software-generated exceptions. Structured exception handling gives developers complete control over the handling of exceptions, provides support for debuggers, and is usable across all programming languages and computers.
style names: One of two attributes used to organize TrueType® fonts. Style names include extra-bold, bold, and italic. (The other attribute used to organize TrueType fonts is the family name.) See also TrueType font.
subclass procedure: An application-defined window procedure that replaces a window's original window procedure when the window is subclassed. See also subclassing, window procedure.
subclassing: A technique that allows an application to intercept and process messages sent or posted to a particular window before the window has a chance to process them. See also subclass procedure.
subdirectory: A directory within another directory. See also directory.
subkey: An entry (or node) in the registry subordinate to a given key. With the exception of four predefined keys, all keys are subkeys of other keys. See also key, registry.
sublanguage identifier: An 8-bit value identifying the variant of a language in a language identifier. See also language identifier, primary language identifier.
Subtractive color mixing: A method of color mixing that uses white as the base color, from which colors may be subtracted. If you begin with white, all colors are present in equal amounts. If you subtract cyan and yellow from white, the resulting image is magenta. In a green image, subtracting cyan will result in changing the image to yellow. The subtractive primary colors are cyan, yellow, and magenta.
subtractive color technology: The color technology, used by ink-based printers, that is based on the three primary colors cyan, yellow, and magenta. Other colors (except white) are obtained by combining two or more of the primaries in varying amounts. White is defined as the absence of the primaries. Black is defined as the presence of all the primaries.
super VGA: A video adapter that supports resolutions higher than 640-by-480 pixels or more than 16 simultaneous colors (or both).
superclass procedure: An application-defined window procedure that replaces the window procedure for a window of a particular window class when the class is superclassed. See also superclassing, window procedure.
superclassing: A technique that allows an application to create a new window class that has the basic functionality of the existing class, but with enhancements provided by the application. See also superclass procedure.
syllabary: A single character that represents what we would call a syllable, using consonant/vowel combinations as their linguistically-discrete units — for example, the sound created by "ta." This term would apply to Kana (Katakana and Hiragana) and Hangul scripts. Linguists use the word "syllabary" to define a system of phonemic (linguistically-distinct) syllabic units used in a language.
synchronization object: An object whose handle can be specified in one of the wait functions to coordinate the execution of multiple threads. Synchronization objects include change notification, console input, event, mutex, process, thread, and semaphore objects. See also object, wait function.
system access-control list (SACL): An ACL that controls the generation of audit messages for attempts to access a securable object. The ability to get or set an object's SACL is controlled by a privilege typically held only by system administrators. See also access-control list (ACL), discretionary access-control list (DACL), privilege.
system directory: The directory that contains Windows libraries, drivers, and font files. See also directory.
system-exclusive data: In Musical Instrument Digital Interface (MIDI), messages understood only by MIDI devices from a specific manufacturer. MIDI device manufacturers can use system-exclusive data to define custom messages that can be exchanged between their MIDI devices. (The standard MIDI specification defines only a framework for system-exclusive messages.) See also Musical Instrument Digital Interface.
System menu: A pop-up menu, defined mainly by the operating system, that typically contains commands used to set a window's size or position, close a window or application, or activate a different application. See also pop-up menu.
system metric: A dimension of a Windows display element, such as the border width, scroll bar arrow height, icon height, and so on. System metrics may also describe other aspects of the operating system, such as whether a mouse is installed, whether the current version of Windows supports double-byte characters, and so on. See also scroll bar.
system paging file: The storage file that the kernel uses to hold pages of memory swapped out of RAM.
system palette: An array that identifies all of the colors that can be displayed simultaneously on a device. For most displays, this array is a subset of all possible colors that can appear on the display.
system time: The "real-time" clock format. System time uses a structure containing individual members for the date and time.