Glossary - S

4 A B C D E F G H I K L M N O P R T U V W X 

Scan Code:  The physical code for a key on the PC keyboard.  For the 
original U.S. English keyboard layout the scan code represents the 
physical position of the key, starting with 1 for the key in the upper 
left corner (Esc), and increasing from left to right and top to bottom. 
 This order will vary for more recent keyboards or those designed for 
other countries or languages. 

Search Path:  See PATH. 

Secondary Shell:  A copy of the command processor which is started by 
another program, rather than by the operating system. 

Session:  A general term for the individual windows or tasks started by a 
multitasking system.  For example, under OS/2 you might run a DOS 
application in one session, and CMD.EXE in another. 

Shell:  See Command Processor.  Also used to refer to a program which 
gives access to operating system functions and commands through a menu- or 
mouse-driven system, or which replaces the primary user interface of the 
operating system. 

Size Range:  A CMD.EXE feature which allows you to select files based on 
their size. 

Source:  In file processing commands (e.g. COPY or MOVE), the original 
files before any copying or modification has taken place, i.e., those 
specified earlier on the command line.  See also Destination. 

Stack:  An area of memory used by any program to store temporary data 
while the program is running; more generally, any such storage area where 
the last item stored is normally the first one removed. 

Standard Error, Standard Input, and Standard Output:  The file(s) or 
character device(s) where a program respectively displays error messages, 
obtains its normal input, and displays its normal output.  Standard error, 
standard input, and standard output normally refer to the console, unless 
redirection is used. 

Subdirectory:  Any directory other than the root directory. 

Subtree:  See Directory Tree. 

Swap File:  A disk file created by an operating system or a program to 
store unused information on disk, and thereby free up memory for other 
purposes. 

Switch:  A parameter for an internal command or application which 
specifies a particular behavior or setting.  For example, the command "DIR 
/P" might be referred to as "having the /P switch set". 

System:  A file attribute indicating that the file belongs to the 
operating system or command processor, and should not be accessed by other 
programs.