The Techref Glossary

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See also:

Access Time
The time it takes to retneve a piece of information. With hard disks or compact discs, maximum access time is measured as the time it takes to move from one end of the disc to the other end.
ANSI
American National Standards Institute
ANSI driver
A device driver, contained in the ANSI.SYS file, that loads additional support for advanced console features. Loaded in the CONFIG.SYS file by a line reading DEVICE=<path>ANSI.SYS. see also: ANSI Standard x3.64 http://wave.campus.luth.se/~pb/comp/standards/ansi_x364.html
application program
A program that performs or replaces a manual function, such as balancing a checkbook or managing inventory.
archive bit
A bit in a file specification used to indicate whether the file in question needs to be backed up. This bit is set every time the file is changed and should be reset by a backup system.
ASCII
American Standard Code for Information Interchange. A coding scheme whereby every character the computer can access is assigned an integer code between 0 and 255.
ASICs
Application Specific Integrated Circuit. like a PAL or GAL but not normally field (or even locally) programmable.
assembly language
A symbolic form of computer language used to program computers at a fundamental level.
asynchronous communications
See serial communications.
Authoring
The process necessary to create an application before the user can start writing on a CD Compact Disc—also called CD, it is a general term for all formats of CD media.
AUTOEXEC.BAT
A batch file executed automatically whenever the computer is booted up.
background task
A second program running on your computer; usually, a printing operation that shares the CPU with your main foreground task.
base name
The portion of a file name to the left of the period separator; it can be up to eight characters long in DOS and Windows 3.x. Windows '95 and Windows NT allow very long file names.
BASIC
Beginner's All-purpose Symbolic Instruction Code. A computer language similar to the English language.
batch file
An ASCII file containing a sequence of DOS commands that, when invoked, will assume control of the computer, executing the commands as if they were entered successively by a computer user.
baud rate
The speed of data transmission, usually in bits per second. SEE ALSO
bit
binary
byte
binary
A numbering system that uses powers of 2 to generate all other numbers. SEE ALSO
baud rate
bit
byte
bit
One-eighth of a byte. A bit is a binary digit, either 0 or 1. SEE ALSO
baud rate
binary
bit mapping
The way a graphics screen is represented in the computer. Usually signifies point-to-point graphics.
BIOS Parameter Block
A portion of every disk's (or Block Device) boot sector that includes essential information such as the number of sectors per track, number of heads, media type, and so on. Extentions to the BPB may contain a disk serial number in DOS 4.0 or later. (see BIOS Parameter Block Extentions)
The BPB is accessed useing Device Driver IOCTL DOS functions Int\21f\44sf\0D 
    Offset Length Name
        -- ------ ---------------------------------
        00 WORD   Bytes per Sector
	02 BYTE   Sectors per Cluster
	03 WORD   Reserved Sectors
	05 BYTE   Number of FATs
	06 WORD   Number of Root Directory Entries
	08 WORD   Total Number of Sectors
	0A BYTE   Media Descripter
	0B WORD   Sectors per FAT
	0D WORD   Sectors per Track
	0F WORD   Number of Heads
	11 DOUBLE Number of Hidden Sectors
	15 DOUBLE RESERVED
	19 6 BYTE RESERVED
BIOS Parameter Block Extensions
An addition to the BIOS Parameter Block added in DOS 4.0 which contains an Information Level(?), Diskett Serial Number, a copy of the volumn lable, and the name of the file system used ('FAT12' or 'FAT16'). May be read or written using undocumented DOS call Int\21f\69 
    Offset Length  Name
	-- ------- ---------------------------------
	00 WORD    Information Level
	02 LONGINT Serial Number
	   11 BYTE Volumn Lable (?)
	   8 BYTE  File System ('FAT12' or 'FAT16')
booting up
See bootstrapping.
boot record
The section on a disk that contains the minimum information DOS needs to start the system.
bootstrapping
When the computer initially is turned on or is rebooted from the keyboard with Ctrl-Alt-Del, it ``pulls itself up by its bootstraps.'' See also warm booting, cold booting.
BPB
see BIOS Parameter Block
BPBE
see BIOS Parameter Block Entension
branching
The transfer of control or execution to another statement in a batch file. See also decision making.
Break key
The control-key combination that interrupts an executing program or command; activated by pressing the Scroll Lock/Break key while holding down the Ctrl key.
buffer
An area in memory set aside to speed up the transfer of data, allowing blocks of data to be transferred at once.
byte
The main unit of memory in a computer. A byte is an 8-bit binary-digit number. One character usually takes up one byte. SEE ALSO
binary
bit
baud rate
cache
A portion of memory reserved for the contents of recently referenced disk sectors. Facilitates faster reaccess of the same sectors.
Carry
Indicates an expansion of the value past the ability of the system to contain it when performing unsigned arithmetic see: Difference between carry and overflow
case sensitivity
Distinguishing between capital letters and lowercase letters.
CCITT
International Telegraph and Telephone Consultative Committee. The body that sets world wide data communication standards such as V.32, V.42, etc..
CD Audio
Standard CD format for storing audio soundtracks (music and songs).
CD-R
Compact disc-recordable
CD-ROM
Compact Disc-Read Only Memory. A standard compact disc used as a digital memory medium for personal computers. Also: A machine language instruction: Complement Read-Only Memory :Q
CD-ROM Drive
A piece of hardware attached to a computer which allows it to read or play a CD-ROM. All CD-ROM players can also play audio CDs.
CD-RW
Compact disc-rewritable. A recent addition to the compact disc family, it is a media and recording system that allows the user to erase previously recorded information and then record new information onto the same physical spot on the disk.
chaining
Passing the control of execution from one batch file to another. This represents an unconditional transfer of control.
character set
A complete group of 256 characters can be used by programs or system devices. Consists of letters, numbers, control codes, and special graphics or international symbols. See also code page.
cluster
A group of contiguous sectors on a disk. This is the smallest unit of disk storage that DOS can manipulate.
COBOL
A programming language usually used for business applications.
code page
A character set that redefines the country and keyboard information for non-n-U.S. keyboards and systems.
cold booting
When the computer's power is first turned on and DOS first boots up. See bootstrapping.
COMMAND.COM
The command processor that comes with DOS.
command line
The line on which a command is entered. This line contains the command and all of its associated parameters and switches. It may run to more than one screen line, but it is still one command line.
command processor
The program that translates and acts on commands.
compressed print
Printing that allows more than 80 characters on a line of output (usually 132 characters, but on newer printers up to 255 characters per line).
computer-aided design (CAD) program
A sophisticated software package containing advanced graphics and drawing features.Used by engineers, architects, and designers for drawing and de-sign applications.
concatenation
The placing of two or more text files together in a series.
conditional statement
A statement in a batch file that controls the next step to be executed in the batch file, based on the value of a logical test.
Confidence
See: Tenacious D: "Tribute"^
CONFIG.SYS
An ASCII text file containing system configuration commands.
configuration
An initial set of system values, such as the number of buffers DOS will use, the number of simultaneously open files it will allow, and the specific devices that will be supported.
console
The combination of your system's monitor and keyboard.
contiguity
That the disk sectors used by a file are physically adjacent on a disk.
control codes
ASCII codes that do not display a character but perform a function, such as ringing a bell or deleting a character.
copy protection
Special mechanisms contained in diskettes to inhibit the copying of them by conventional commands.
"Probably the dumbest idea ever foisted on the computer-user public. There have been scads of copy protection schemes--from running programs off of special laser-burned disks, to plugging a hardware key into the computer. The hardware key idea I can see for very expensive professional software, but the other methods are just bogus. Even software publishers have figured this out and they've quit doing it in most cases. Having to put in a boot disk every time you bring up the spreadsheet that you use a zillion times a day just doesn't make sense. The best copy protection is to make the software so inexpensive relative to its usefulness, and the support so valuable, that users are willing to buy the license to maintain the
support. Publishers need to realize that a person who rips off an expensive business program to keep track of his record collection is not really a lost sale. This would select a cheaper product if he were to buy one; and he's gaining valuable experience with the program, making him more likely to buy it later in another business application." Digital Dave 1992
CPLDs
Complex Programmable Logic Devices. The xilinx name for high end ISPGALs.
CPU
Central Processing Unit. The main chip that executes all individual computer instructions.
CRC
see Cyclic Redundancy Check
Ctrl-Z
The end-of-file marker.
cursor
The blinking line or highlighted box that indicates where the next keystroke will be displayed or what the next control code entered will affect.
cutting and pasting
Selecting text from one part of a document or visual display and moving it to another location.
Cyclic Redundancy Check
A system for the detection of errors in data transmitions. CRC is commonly used in disk drives, modems, and other devices to detect data loss. CRC has an advantage over VRC (parity) error checking in that its chances of detecting an error are higher (99.99% vice 90%) and its overhead is less if more than 8 characters are sent at a time. CRC considers all the data sent in a block as one huge number and divides it by a binary divisor to generate a remainder which is appended to the block of data and transmitted to the reciever. The reviever re-calculates the remainder and compaires this value with the transmitted remainder. A difference indicates transmition errors and will prompt the reciever to request retransmission
of the block. The most common CRC systems, CRC-16 or CRC-CCITT, use a 16 bit divisor.
A CRC algorithm can be found in David Schwaderer's excellent book "C
Programmers Guide to NetBIOS" published by Howard W. Sams & Co. Inc.
A CRC-32 algorithm can be found in Dr Dobbs Journal May 1992 Pg 64
cylinder
Two tracks that are in the same place on different sides of a double-sided disk. May be extended to include multiple platters. For example, Side 0 Track 30, Side 1 Track 30, Side 2 Track 30, and Side 3 Track 30 form a cylinder.
daisy-wheel printer
A printer that uses circular templates for producing letter-quality characters.
data area
The tracks on a disk that contain user data.
database
A collection of data organized into various categories. A phone book is one form of database.
database management system
A software program designed to allow the creation of specially organized files, as well as data entry, manipulation, removal, and reporting for those files.
data bits
The bits that represent data when the computer is communicating.
data disk
A disk that has been formatted without the /S switch. The disk can contain only data; no room has been reserved for system files.
data stream
The transmission of data between two components or computers.
Datum:
symbol that describes an aspect of an entitiy or event in the real world. Statistical datatypes:
dead key
A reserved key combination on international keyboards, which outputs nothing itself but allows the next keystroketo produce an accent mark above or below the keystroke's usualcharacter.
debugging
The process of discovering what is wrong with a program, where the problem is located, and what the solution is.
decimal
A numbering system based on ten digits.
decision making
A point in a batch file at which execution can continue on at least two different paths, depending on the results of a program test. Also known as logical testing or branching.
default
The standard value of a variable or system parameter.
deferred execution
In a program or batch file, when execution is delayed until a value for some parameter is finally entered or computed.
delimiter
A special character, such as a comma or space, used to separate values or data entries.
Delphi
A Rapid Application Development language from Borland International
destination
The targeted location for data, files, or other information generated or moved by a DOS command.
device
Any internal or external piece of peripheral hardware.
device driver
Also known as an interrupt handler. A special program that must be loaded to use a device. Adds extra capability to DOS.
device name
Logical name that DOS uses to refer to a device.
digital
A representation based on a collection of individual digits, such as 0s and 1s in the binary number system.
digitizer
A device with a movable arm that can take an image and break it up into small parts, which the computer translates into bits.
directory
A grouping of files on a disk. These files are displayed together and may include access to other directories (subdirectories). SEE ALSO
directory tree
file
path
subdirectory
directory tree
The treelike structure created when a root directory has several subdirectories, each of the subdirectories has subdirectories, and so on. SEE ALSO
directory
file
path
subdirectory
disk drive
A hardware device that accesses the data stored on a disk. SEE ALSO
hardware
diskette
A flexible, oxide-coated disk used to store data. Also called a floppy diskette. SEE ALSO
disk drive
hardware
disk optimizer
A program that rearranges the location of files stored on a disk in order to make the data in those files quickly retrievable.
DOS
Disk Operating System. A disk manager and the program that allows computer / user interaction.
DOS environment
A part of memory set aside to hold the defaults needed in the current environment, such as COMSPEC, PATH, LASTDRIVE, and so on.
DOS prompt
Usually C or A. The visual indication that DOS is waiting for a command or prompting you for input.
dot-matrix printer
A printer that represents characters by means of tiny dots.
double-density diskette
A diskette on which magnetic storage material is arranged twice as densely as usual, allowing the storage of twice the usual amount of data. Generally refers to a 360K, 5-inch diskette.
drive identifier
A single letter assigned to represent a drive, such as drive A or drive B. Usually requires a colon after it, such as A:.
DRIVER.SYS
A file containing a device driver for an extra external disk drive. Used in the CONFIG.SYS file.
dual tasking
Causing two tasks or programming events to occur simultaneously.
DVD
Digital Video Disc or Digital Versatile Disc. A sort of Usuper" CD, with enhanced storage capacity.
EBCDIC
Extended Binary Coded Decimal  Interchange Code.
echoing
Displaying on your video monitor the keystrokes you type in.
EDLIN
The DOS line editor.
end-of-file marker
A Ctrl-Z code that marks the logical end of a file.
Engineers
The Oompa-Loompas of science
environment
The context within which DOS interfaces with you and with your commands.
error level
A code, set by programs as they conclude processing, that tells DOS whether an error occurred, and if so, the severity of that error.
expansion cards
Add-on circuit boards through which hardware can increase the power of the system, such as adding extra memory or a modem.
expansion slots
Connectors inside the computer in which expansion cards are placed so that they tie in directly to the system.
extended ASCII codes
ASCII codes between 128 and 255, which usually differ from computer to computer.
extended DOS partition
A hard-disk partition used to exceed the 32 megabyte, single-disk barrier; it can be divided into logical disk drives.
extended memory
Additional physical memory beyond the DOS 1 megabyte addressing limit.
extension
The one to three characters after the period following the base name in a file specification.
external buffer
A device, connected to the computer and another device, that acts as a buffer.
file
A collection of bytes, representing a program or data, organized into records and stored as a named group on a disk. SEE ALSO
directory
directory tree
path
subdirectory
file allocation table (FAT)
A table of sectors stored on a disk, which tells DOS whether a given sector is good, bad, continued, or the end of a chain of records.
file name
The name of a file on the disk. Usually refers to the base name, but can include the extension as well.
file version
A term that refers to which developmental copy of a software program is being used or referenced.
filter
A program that accepts data as input, processes it in some manner, and then outputs the data in a different form.
fixed disk
IBM's name for a hard disk.
FLASH
A type of non-volitile memory
floppy diskette
See diskette.
flow of control
The order of execution of batch file commands; how the control flows from one command to another, even when the next command to be executed is not located sequentially in the file.
foreground task
The main program running on your computer, as opposed to the less visible background task (usually a printing job).
formatting
The placement of timing marks on a disk to arrange the tracks and sectors for subsequent reading and writing.
FPGAs
Field Programmable Gate Arrays. The xilinx name for low end ISPGALs.
fragmentation
A condition in which the parts of many files have been stored in noncontiguous sectors on a disk or other storage media. Garbage Collection or De-Fragmentation systems are used to reorder media in this condition and provide faster contiguous file access.
function keys
Special-purpose keys on a keyboard, which can be assigned unique tasks by DOS or by application programs.
GAL
Gate Array Logic
giga
1,000,000,000. a prefix meaning one billion.
gigabyte (GB)
1,073,741,824 bytes. aka gibi a kilo, kilo, kilo byte or a kilo mega byte.
global characters
See wildcards.
Gold Disc
A blank recordable disc used in recordable CD systems which contauns a reflective hyer of gold.
graphics mode
The mode in which all screen pixels on a monitor are addressable and can be used to generate detailed images. Contrasts with text mode, which usually allows only 24 lines of 80 characters.
hard disk
A rigid platter that stores data faster and at a higher density than a floppy diskette. Sealed in an airtight compartment to avoid contaminants that could damage or destroy the disk. SEE ALSO
active partition
head
hardware
hardware
The physical components of a computer system. SEE ALSO
active partition
diskette
hard disk
disk drive
hardware interrupt
A signal from a device to the computer, indicating that an event has taken place.
head
A disk-drive mechanism that reads data from and writes data to the disk. SEE ALSO
hard disk
head crash
head crash
Occurs when the head hits the disk platter on a hard disk, physically damaging the disk and the data on it. SEE ALSO
head
help file
A file of textual information containing helpful explanations of commands, modes, and other on-screen tutorial information.
hexadecimal
A numbering system in base 16. A single 8-bit byte can be fully represented as two hexadecimal digits.
hidden files
Files whose names do not appear in a directory listing. Usually refers to DOS' internal system files, but can also refer to certain files used in copy-protection schemes.
high-capacity diskette
A 1.2 megabyte, 5--inch floppy diskette.
high-resolution mode
The mode on a video monitor in which all available pixels are used to provide the most detailed screen image possible. On a color monitor, this mode reduces the possible range of colors that can be output.
horizontal landscape
When output to a printer is not done in the usual format, but rather with the wider part of the paper laid out horizontally, as in a landscape picture.
hot key
A key combination used to signal that a memory-resident program should begin operation.
housekeeping
Making sure the directory stays intact and well organized, and that unnecessary files are deleted.
hub
The center hole of a diskette.
IF
A conditional statement in a batch file or computer language.
ink-jet printer
A printer that forms characters by spraying ink in a dot pattern. See dot-matrix printer.
interface
The boundary between two things, such as the computer and a peripheral.
interrupt
A signal sent to the computer from a hardware device, indicating a request for service or support from the system.
ISO 9660 Format
An international standard specifying the log ical format for files and directories on a CD-ROM. It allows different computers with unlike operating systems to access the same data.
ISP PLDs
In System Programmable Programmable Logic Devices
keyboard translation table
An internal table, contained in the keyboard driver, that converts hardware signals from the keyboard into the correct ASCII codes.
key combination
When two or more keys are pressed simultaneously, as in Ctrl-Scroll Lock or Ctrl-Alt-Del.
key redefinition
Assigning a nonstandard value to a key.
Kilo
1000. A prefix meaning one thousand, as in 100 kiloton or 100,000 tons.
kilobyte (KB) aka Kibi
1024 bytes. NOT 1000 bytes.
laser printer
A printer that produces images (pictures or text) by shining a laser on a photostatic drum, which picks up toner and then transfers the image to paper.
LCD
Liquid Crystal Display. A method of producing an image using electrically sensitive crystals suspended in a liquid medium.
letter-quality printer
A printer that forms characters that are comparable to those of a typewriter.
line editor
A program that can make textual changes to an ASCII file, but can only make changes to one line of the file at a time.
line feed
When the cursor on a screen moves to the next line, or when the print head on a printer moves down the paper to the next line.
literal
Something that is accepted exactly as it was submitted.
lockup
Occurs when the computer will not accept any input and may have stopped processing. Requires that the computer be warm or cold booted to resume operating.
log file
A separate file, created with the BACKUP command, that keeps track of the names of all files written to the backup diskette(s).
logging on
Signing onto a remote system, such as a mainframe or telecommunications service.
logical
Something that is defined based on a decision, not by physical properties.
logical drives
Disk drives, created in an extended DOS partition, that do not physically exist, but DOS operates as if they do. A means for DOS to access a physical disk that has more than 32 megabytes available.
logical testing
See decision making.
look and feel
"The appearance of a user interface. Apple Computer tried to claim that any program that "looked like and felt like" its operating system was an infringement on its copyrights. It ignored the fact that the programs ran on completely different computers, and that most of the features were developed previously by others. This is one thing that sours me on Apple. If it can't make it in the marketplace, it tries to make money by suing others. So far it doesn't seem to be making much profit this way either. Thank goodness. This is what happens when the bean counters and legal beagles take over from the techies." Digital Dave 1992
machine language
The most fundamental way to program a computer, using instructions made up entirely of strings of 0sand 1s.
macro
A set of commands, often memory-resident. When executed, they appear to the program executing them as if they were being entered by you.
Mastering
in mass production, the process of creating a glass master from which stamped compact discs will be made. In desktop recordable systems, mastering is done with a desktop CD recorder, and can be referred to as Recording.
medium-resolution mode
The mode on a Color Graphics Adapter in which only 320x200 pixels of resolution are allowed.
mega
1,000,000 or 106. A prefix meaning one million. As in 100 megaton or 100,000,000 tons.
megabyte (MB)
1,048,576 or 1024 kilobytes. aka mebi Defined (misleadingly) by manufacturers of hard drives as 1,000,000 bytes. A 1.44 MB diskett holds 1,024,000 bytes or a Kilo Kibi Bytes.
memory
The circuitry in a computer that stores information. See also RAM and ROM.
memory-resident
Located in physical memory, as opposed to being stored in a disk file.
menu
A set of choices displayed in tabular format.
meta symbols
Special single-character codes used by the PROMPT command to represent complex actions or sequences to be included in the DOS prompt.
Micro Controllers
A compact (generally single chip) combination of a CPU and most of the support circuitry required to provide an intelligent control system for some device.
microfloppy diskette
The 3-inch diskette format used in the IBM PS/2 and many other computers.
Micro Processors
A compact (generally single chip) CPU
MIPS
Million Instructions Per Second. A measure of the processing speed of a Micro
modem
A device that transmits digital data in tones over a phone line.
monitor
The device used to display images; a display screen.
monochrome
Using two colors only: the background and foreground.
mouse
A device that moves the screen cursor by means of a hand-held apparatus moved along a surface such as a desk. The computer can tell how far and in which direction the mouse is being moved.
MPEG
Motion Picture Experts Group. The group's name has been applied to the standard that has become accepted for compression of certain full-motion videos.
multitasking
When two or more computing applications are executing simultaneously. Multitask is support for multiple concurrent tasks, time switched on a regular schedule. Tasks each have their own data and code space.
Multithread
A subset of multitasking. Threads usually share data space, but have their own code space.
national language-support operations
The DOS 3.3 feature that supports displays and printers, using a new range of code and character groupings.
network
Several computers, connected together, that can share common data files and peripheral devices.
nibble
Four bits, or half a byte.
octal
A numbering system in base 8.
operating system
See DOS.
Overflow
Indicates an expansion of the value past the ability of the system to contain it when performing signed arithmetic see: Difference between carry and overflow
overlay files
Files containing additional command and control information for sophisticated and complex programs. An overlay file is usually too large to fit into memory along with the main .EXE or .COM file.
overwriting
Typing new data over what is already there.
PLDs
Programmable Logic Devices
Packet Writing
A method of writing data on a CD in small increments, as opposed to writing large blocks of information as required by other methods.
parallel communications
Data transmission in which several bits can be transferred or processed at one time.
parameter
An extra bit of information, specified with a command, that determines how the command executes.
parity bit
The bit, added to the end of a stream of data bits, that makes the total of the data bits and the parity bits odd or even.
partition
The section of a hard disk that contains an operating system. There can be at most four partitions on one hard disk.
Pascal
A programming language used mainly in computer science.
password
A sequence of characters that allows entry into a restricted system or program.
path
The list of disks and directories that DOS will search through to find a command file ending in .COM, .BAT, or .EXE. SEE ALSO
directory
directory tree
file
subdirectory
peripheral
Any physical device connected to the computer.
piping
Redirecting the input or output of one program or command to another program or command.
pixel
The smallest unit of display on a video monitor- -in short, a dot- -that can be illuminated to create text or graphics images.
platter
The rigid disk used in a hard disk drive.
plotter
A device that draws data on paper with a pen held in a mechanical arm.
port
A doorway through which the computer can access external devices.
primary DOS partition
Up to the first 32 megabytes of a hard disk. Contains the boot record and other DOS information files.
printer
A device that outputs data onto paper using pins (dot matrix), a daisy wheel, ink jets, laser imaging, and so on.
protected mode
In protected mode, available in the 80286,80386, and 80486 microprocessors, applications are kept separate and do not know that other applications are running concurrently. The benefit is that if one program fails or acts unpredictably, the OS can safely abort the errant program but leave the other alone. In a well implemented protected mode environment, an ill-behaved program does not "crash"; it is "terminated" by the operating system. Protected mode operating systems provide more protection against malicious attacks by virus programs. OS/2, Desqview, Windows 3.0, and Unix all use protected mode for multitasking and to protect applications from one another.
public domain
Something not copyrighted or patented. Public domain software can be used and copied without infringing on anyone's rights.
queue
A series of files waiting in line to be printed.
RAM
Random Access Memory. The part of the computer's memory to which you have access; stores programs and data while the computer is on.
RAM disk
An area of RAM that acts as if it were a disk drive. All data in this area of memory is lost when the computer is turned off or warm booted. Also known as a virtual disk.
range
A contiguous series of values (minimum to maximum, first to last, and so on).
read-after-write verification
An extra level of validity checking, invoked with the VERIFY command or the /V switch. Rereads data after writing it to disk, comparing the written data to the original information.
read-only status
Indicates that a file cannot be updated but can be read.
read/write bit
The bit in a file specification that indicates whether a file can accept changes or deletions, or can only be accessed for reading.
redirection
Causing output from one program or device to be routed to another program or device. Most command line oriented DOS programs accept input from the STDIN device driver and output to STDOUT. These streams can be redirected on the command line useing the '>' and '<' characters. '<' redirects STDIN causeing input to the program to come from a file or device instead of from the keyboard. Output can be redirected use the '>'.
EXAMPLE:
C:\DEBUG < SHIFTOFF.SCR
Will cause the contents of the file SHIFTOFF.SCR to be sent to DEBUG.COM just as though the user had typed this file into the program.
C:\DIR REPORT.TXT
Will cause a listing of files in the root directory to be sent to a text file called REPORT.TXT.
Redirection of STDIN and STDOUT can be detected by INT\21F\44SF\00.
REM statement
A line in a BASIC program containing remarks or comments for program explanation or clarification.
reserved names
Specific words, in a programming language or operating system, that should not be used in any other application context.
resident commands
Commands located in random access memory.
resource allocation
Making system facilities available to individual users or programs.
reverse video
Black letters on a white background.
ROM
Read-Only Memory. The section of memory that you can only read from. This contains the basic computer operating system and system routines.
root directory
The first directory on any disk.
scan code
The hardware code representing a key pressed on a keyboard. Converted by a keyboard driver into an ASCII code for use by DOS and application programs.
scrolling
What the screen does when you're at the bottom of it and press Return- -all of the lines roll up.
SCSI
Small Computer System Interface (pronounced "scuzzy"). A standard tor high-speed data transfer between computers and their peripheral devices.
secondary command processor
A second copy of COMMAND.COM, invoked either to run a batch file or to provide a new context for subsequent DOS commands.
sector
A division of a disk track; usually, 512 bytes.
serial communications
Data transmission in which data is transferred and processed one bit at a time. Also known as asynchronous communications.
shareware
Public domain software. See also public domain.
site license
"A type of software license used by large companies to ease the headaches of keeping track of individual licenses. Unrestricted site licenses allow anyone or everyone in the company to use a piece of software at one time. Some licenses have restrictions, like the number of users at one time. It's easy on a local area network to set it up so that only a certain number of people can run the program at once. When one person quits, another can then start a version of it. In these days of multi-user and multi-CPU systems, this can get complicated. If one user runs the program on a machine that has four CPUs, does he count as one user or four? Licenses like this are a boon to the hardware manufacturers. It's often cheaper to go out and buy faster computers than to pay for more licenses." Digital Dave 1992
snapshot program
A program used in debugging to store the status of system or application program variables.
software
The programs and instruction sets that operate the computer.
software interrupt
A signal from a software program that calls up a routine that is resident in the computer's basic programming. Also, a software signal to the computer that the software program has finished, has a problem, and so on.
software license
"When you get that shrink-wrapped software home and rip it open, you haven't purchased the software in the box. You bought a license to use the software. That's good. If the publisher sold you only the software, you'd get what's in the box and that's all. Usually it's in the publisher's best interest to support their licensee, so you actually bought technical support that will help you use the product. If there is a big "oops" in the software, the publisher has a reason to develop a fix and send it out to the licensees right away. Read the license that comes with your software. Some of it is pretty funny. Some publishers put it in plain language for us non-lawyers, and maybe even give an example to illustrate. Smart." Digital Dave 1992
source
The location containing the original data, files, or other information to be used in a DOS command.
spooling
Simultaneous Peripheral Operations On-Line. Using a high-speed disk to store input to or output from low-speed peripheral devices while the CPU does other tasks.
spreadsheet program
An electronic version of an accountant's spreadsheet; when one value changes, all other values based on that value are updated instantly.
start bit
The bit sent at the beginning of a data stream to indicate that data bits follow.
Statistical Data Types
Nominal:
Names datum. E.g. Persons Name, sex, address, phone number
Ordinal:
positional when interval not exactly defined. E.G. Soldier rank; Captain is higher than lieutenant and lower than major but the distance is not defined precisely.
Interval:
Point on a scale with defined interval but no zero point. E.g.
Years of time. The year 2000 is exactly 1000 years after the year 1000 but is not twice as far from the beginning of time.
Ratio:
Point on a scale with defined interval and orgin. E.g. Temperature as degrees kelvin.
stop bit
The bit sent after the data bits, indicating that no more data bits follow.
string
A series of characters.
subcommands
Several special commands used only within batch files.
subdirectory
A directory contained within another directory or subdirectory. Technically, all directories other than the root directory are subdirectories.
SEE ALSO
directory
directory tree
file
path
switch
A parameter included in DOS commands, usually preceded by the slash (/) symbol, that clarifies or modifies the action of the command.
synchronization
The coordination of a sending and receiving device, so that both simultaneously send and receive data at the same rate.
system disk
A disk containing the necessary DOS files for system booting.
text mode
The mode in which standard characters can be displayed on a monitor.
time slice
The smallest unit of time managed and assigned by the operating system to programs and other processing activities.
toggle
A switch or command that reverses a value from off to on, or from on to off.
track
A circular stream of data on the disk. Similar to a track on a record, only not spiraling.
transient command
A command whose procedures are read from the disk into memory, executed from memory, and then erased from memory when finished.
TUCOWS
(The Ultimate Collection Of Winsock Software)
utility
A supplemental routine or program designed to carry out a specific operation, usually to modify the system environment or perform housekeeping tasks.
variable parameter
A named element, following a command, that acts as a placeholder; when you issue the command, you replace the variable parameter with the actual value you want to use.
verbose listing
A listing of all files and subdirectories contained on the disk and path specified in the command. Activated by the CHKDSK command with the /V switch.
vertical portrait
The conventional 8-by-11-inch output for printed information, with the long side of the paper positioned vertically.
virtual disk
See RAM disk.
volume label
A name, consisting of up to 11 characters, that can be assigned to any disk during a FORMAT operation or after formatting with the LABEL command.
warm booting
Resetting the computer using the Ctrl-Alt-Del key combination.
See bootstrapping.
Wave
A Wave file (. WAV) is a type of sound file w hich stores digitized analog signals
wide directory listing
An alternate output format that lists four columns of file names.
wildcards
Characters used to represent any other characters. In DOS, * and ? are the only wildcard symbols.
word processor
A computerized typewriter. Allows the correction and reformatting of documents before they are printed.
write-protection
Giving a disk read-only status by covering the write-protect notch.

Also:

BCD (Binary Coded Decimal)
just the binary representation of each digit in a decimal number. So, you could convert binary to decimal then convert each digit of the decimal number into a binary value. For example: 4096 would be 00000100 00000000 00001001 00000110
Packed BCD
where each Decimal digit is stored in a four bit value in the high or low "nibble" of a byte. For example: 4096 would be written as 01000000 10010110

Code:

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