Glossary
Glossary
A
- ACK
- An acknowledgment signal.
- Advanced Power Management (APM)
- (1) A software interface (defined by Microsoft and Intel) between
hardware-specific power management software (such as that located
in a system BIOS) and an operating system power management driver.
(2) An abridgment of the Advanced Power Management (APM) BIOS
Interface Specification title.
- Advanced System Configuration and Power Interface (ACPI)
- A specification that defines the power management, Plug and Play,
and system BIOS interfaces for the system board and operating
system.
- API
- Acronym for application programming interface. This is a set of
routines that an applications program uses to request and carry
out lower-level services performed by the operating system.
- APM
- See Advanced Power Management.
- Arbitrator
- A software module in Windows that handles the allocation of hardware
resources among devices.
- ASIC
- Acronym for application-specific integrated circuit.
- ATA
- Acronym for AT Attachment. Used interchangeably with Integrated
Drive Electronics (IDE).
- ATAPI
- See AT Attachment Packet Interface.
- AT Attachment (ATA)
- An integrated bus generally used between host processors and disk
drives.
- AT Attachment Packet Interface (ATAPI)
- A hardware and software specification that documents the interface
between a host computer and CD-ROM drives using the ATA bus.
B
- buffer
- A reserved portion of memory in which data is temporarily held,
pending an opportunity to complete its transfer to or from a storage
device or another location in memory.
- buffering
- The process of using buffers to hold data that is being transferred,
particularly to or from I/O devices such as disk drives and serial
ports.
- bus enumerator
- A bus device driver that detects devices located on a specific
bus and loads information about devices into the hardware tree.
C
- Card select number
- The handle created by the system BIOS or the operating system
through the isolation process, and assigned to each Plug and Play
card on the ISA bus as a unique identifier.
- Card Services
- A system component that is a protected-mode VxD, linked with the
PC Card bus driver. The Card Services component passes the event
notification from socket services to the PC Card bus driver, provides
information from the computer's cards to the PC Card bus driver,
and sets up the configuration for cards in the adapter sockets.
- CDFS
- Compact disc file system, which controls access to the contents
of CDROM drives.
- class
- For hardware, the manner in which devices and buses are grouped
for purposes of installing and managing device drivers and allocating
resources. The hardware tree is organized by device class, and
Windows 95 uses class installers to install drivers for all hardware
classes.
- codec
- Compression/decompression technology for digital video and stereo
audio.
- Compatibility mode
- An asynchronous, host-to-peripheral parallel port channel defined
in the IEEE 1284-1994 standard. This mode is compatible with existing
peripherals that attach to the Centronics-style PC parallel port.
- Configuration Manager
- The central component of a Plug and Play system that drives the
process of locating devices, setting up their nodes in the hardware
tree, and running the resource allocation process. Each of the
three phases of configuration management - boot time (BIOS), real
mode, and protected mode - has its own configuration manager.
- conflict
- See resource conflict.
- CSN
- See card select number.
D
- DDC
- Acronym for display data channel, the communications channel between
a monitor and the display adapter to which it is connected. This
channel provides a method for the monitor to convey its identity
to the display adapter.
- device
- Any circuit that performs a specific function, such as a parallel
port or graphics adapter.
- device ID
- A device identification string, in many cases beginning with a
three-letter standard EISA identifier, that distinguishes each
logical device and bus from all others on the system.
- device node
- The basic data structure for a given device, built by Configuration
Manager in Windows 95; sometimes called devnode. Device nodes
are built into memory at system startup for each device and enumerator
with information about the device, such as currently assigned
resources. The complete representation of all device nodes is
referred to as the hardware tree.
- DIB
- Acronym for device-independent bitmap.
- digital signal processor (DSP)
- An integrated circuit designed for high-speed data manipulations,
used in audio, communications, image manipulation, and other data-acquisition
and data-control applications.
- direct memory access (DMA)
- A method of moving data from a device to memory (or vice versa)
without the help of the microprocessor. The system board uses
a DMA controller to handle a fixed number of "channels,"
each of which can be used by only one device at a time.
- disk I/O controller
- A special-purpose chip and circuitry that directs and controls
reading from and writing to a computer's disk drive.
- DLL
- Acronym for dynamic-link library. A programming interface (API)
routine that user-mode applications access through ordinary procedure
calls. The code for the API routine is not included in the user's
executable image. Instead, the operating system automatically
modifies the executable image to point to DLL procedures at run
time.
- DMA
- See direct memory access.
- dock
- To insert a portable computer into a base unit. Cold docking means
the computer must begin from a power-off state and restart after
docking. Hot docking means the computer can be docked while running
at full power.
- docking station
- The base computer unit into which a user can insert a portable
computer to expand it to a desktop equivalent. A typical dock
provides drive bays, expansion slots, all the ports on the desktop
computer, and AC power.
- dongle
- A physical device attached to a PC I/O port to add hardware
capabilities.
- DSP
- See digital signal processor.
- dynamic detection
- The process by which a Plug and Play system can detect that a
new device has been added or removed from the PC. This process
allows the operating system and applications to begin using the
added devices immediately or stop using the removed devices without
rebooting the system.
E
- ECP
- Acronym for extended capabilities port. An asynchronous, 8-bit-wide
parallel channel defined by IEEE 1284-1994 that provides PC-to-peripheral
and peripheral-to-PC data transfers.
- EISA
- Acronym for Extended Industry Standard Architecture bus.
- Energy Star
- Abridgment of EPA Energy Star computers. A program initiated by
the U.S. Environmental Protection Agency and computer manufacturers
documenting standards of power management designed to reduce the
electricity load of computer systems in the commercial sector.
Computers that meet the requirements of the Energy Star program
qualify for the Energy Star logo.
- enumeration
- The process by which logical devices and buses, and their available
resources, are identified in a Plug and Play system.
- enumerator
- A Plug and Play system component that takes responsibility for
detecting logical child devices and reports the existence of those
devices to the configuration manager during startup.
- expansion bus
- A group of address, data, and control lines that provide a buffered
interface to devices located either on the system board or on
cards that are plugged into expansion connectors. Expansion buses
on the system board can include the USB, PC Card, PCI, and other
buses.
- expansion card
- A card that connects to an expansion bus and that contains one
or more devices.
- expansion ROM
- See option ROM.
F
- FDC
- Acronym for floppy disk drive controller.
- FIFO
- Acronym for first in, first out. A method for processing a queue
in which items are removed in the same order they were added.
H
- Hardware Compatibility Tests
- A suite of tests prepared by Windows Hardware Quality Laboratory
(WHQL) that verify hardware and device driver operation under
a specific operating environment. These tests exercise the combination
of a device, a software driver, and an operating system under
controlled conditions to verify that all components operate properly.
- hardware tree
- A record in RAM of the cur-
rent system configuration, based on the configuration information
for all devices in the hardware branch of the Registry. The hardware
tree is created each time the computer is started or whenever
a dynamic change occurs to the system configuration.
- HCT
- See Hardware Compatibility Tests.
- HDC
- Acronym for hard disk controller. See Disk I/O Controller.
- hot docking
- A system design to support removing or installing a mobile system
in a docking station, while the computer is running at full power.
I
- IDE
- Acronym for Integrated Device Electronics. A type of disk-drive
interface where the controller electronics reside on the drive
itself, eliminating the need for a separate adapter card.
- IHV
- Acronym for independent hardware vendor.
- I/O
- Acronym for input/output. Two of the three activities that characterize
a computer: input, processing, and output. This refers to the
complementary tasks of gathering data for the microprocessor to
work with and making the results available to the user through
a device such as the monitor, disk drive, or printer.
- INF file
- A file created for a particular adapter that provides the Windows
Setup program with the information required to set up that device,
such as a list of valid logical configurations for the device,
the names of driver files associated with the device, the values
to be added or changed in the registry, and so on.
- integrated devices
- Any devices, such as parallel ports, graphics adapters, and so
on, that are designed on the system board rather than on an expansion
card.
- IPL
- Acronym for initial program load. A device used by the system
during the boot process to load an operating system into memory.
- IrDA
- Acronym for Infrared Data Association.
- IRP
- Acronym for I/O request packet. Data structures that drivers use
to communicate with each other.
- IRQ
- Acronym for interrupt request. A method by which a device can
request to be serviced by the device's software driver. The system
board uses a programmable interrupt controller (PIC) to monitor
the priority of the requests from all devices. When a request
occurs, the microprocessor suspends the current operation and
gives control to the device driver associated with the interrupt
number issued. The lower the number for example, IRQ 3, the higher
the priority of the interrupt.
- ISA
- Acronym for Industry Standard Architecture bus. An expansion bus
that provides a buffered interface from devices on expansion cards
to the PC internal bus.
- isolation
- The process by which cards on an ISA bus are distinguished from
each other after system startup.
K
- kernel
- The portion of Windows that manages the processor.
L
- legacy
- A colloquial description usually referring to older devices or
systems that are not Plug and Play compatible.
- local bus
- Generally refers to a system bus directly connected to the microprocessor
on a system board. Used colloquially to refer to system board
buses located closer to the microprocessor than are ordinary expansion
buses (that is, with less buffering), which are therefore capable
of greater throughput. The PCI bus is often referred to as a local
bus.
M
- minidriver
- A device driver that contains hardware-specific code related to
a specific hardware device. The Win32 Driver Model allows hardware
manufacturers to implement minidrivers.
- miniport driver
- A 32-bit installable driver. Windows NT was the first operating
system to use miniport drivers.
- motherboard
- See system board.
- MPEG
- Acronym for Motion Picture Experts Group, used when referring
to one of several standard video-compression schemes.
N
- NDIS
- Acronym for Network Driver Interface Specification. NDIS provides
transport independence for network vendors. All transport drivers
call the NDIS interface to access network.
- nibble mode
- An asynchronous, peripheral-to-host channel defined in the IEEE
1284-1994 standard. This mode provides a channel for the peripheral
to send data to the host, which is commonly used to identify the
peripheral.
- NMI
- Acronym for Nonmaskable Interrupt. An interrupt that cannot be
overruled by another service request; called nonmaskable because
it bypasses and takes priority over interrupt requests generated
by software, the keyboard, and other devices.
- NTFS
- Windows NT File System. An advanced file system designed for use
specifically with the Windows NT operating system. NTFS supports
file system recovery and extremely large storage media, in addition
to other advantages.
O
- OEM
- Acronym for original equipment manufacturer, used in this guide
primarily to refer to PC systems manufacturers.
- option ROM
- Optional read-only memory found on expansion cards. This ROM usually
contains additional firmware required to properly boot the peripheral
connected to the expansion card, for example, a hard drive. Also
referred to as an expansion ROM.
P
- packed-pixel frame buffer
- A portion of the display memory that holds the contents of a single
screen image with screen bits stored in a single plane, with each
pixel on the screen having a set of two or more corresponding
bits that define the pixel color.
- PCI
- Acronym for Peripheral Component Interconnect. A high-performance
32-bit or 64-bit bus designed to be used with devices that have
high bandwidth requirements, such as the graphics subsystem.
- PCMCIA
- Acronym for Personal Computer Memory Card International Association.
Usually used to refer to a controller for PC Card expansion cards
as documented in the PCMCIA standards.
- PIC
- Acronym for programmable interrupt controller.
- Planar
- See system board.
- Plug and Play
- A design philosophy and a set of specifications that describe
hardware and software changes to the PC and its peripherals for
automatically identifying and arbitrating resource requirements
among all devices and buses on the system.
- PnP
- See Plug and Play.
- port
- A connection or socket used to connect a device such as a printer,
monitor, or modem to the computer. Information is sent from the
computer to the device through a cable.
- port replicator
- Low-cost docking station substitute, intended to provide convenient,
one-step connection to multiple desktop devices.
- POST
- Acronym for power-on self test. A procedure of the system BIOS
that identifies, tests, and configures the PC in preparation for
loading the operating system.
R
- RAMDAC
- Acronym for random access memory digital-to-analog converter.
A chip built into some VGA and SVGA display adapters that translates
the digital representation of a pixel into the analog information
needed by the monitor to display it. The presence of a RAMDAC
chip generally enhances overall display performance.
- Red Book audio
- The data format standard for conventional audio CDs used in home
stereo systems.
- registry
- The tree-structured hierarchical database in which system hardware
and software settings are to be stored. The registry supersedes
use of separate INI files.
- resource arbitrator
- A set of functions used by Configuration Manager to arbitrate
and allocate resources on the PC.
- resource conflict
- The result of more than one device sharing the same non-sharable
resource. Conflicts can cause the device to be partially functional
or nonfunctional, or might cause the PC to malfunction completely.
- resource data type function
- A function that describes the resource requirements of an ISA
expansion card, along with the programmability available on the
card and its interdependencies.
- resources
- A general term that refers to interrupt request (IRQ) signals,
direct memory access (DMA) channels, I/O port addresses, and memory
addresses.
- RLE
- Acronym for run-length encoding, a data compression scheme technique
in which successive bytes of identical data are converted to a
2-byte pair, consisting of the repeated data byte and the repeat
count.
S
- SCAM
- Acronym for SCSI configured automatically.
- SCSI
- Acronym for small computer system interface. An I/O bus designed
as a method of connecting several classes of peripherals to a
host system without requiring modifications to generic hardware
and software.
- SPI
- Acronym for SCSI-3 parallel interfaces.
- spin down
- A power management capability in which a hard drive shuts down
its spindle motor.
- static resources
- Device resources, such as IRQ signals, DMA channels, I/O port
addresses, and memory addresses, that cannot be configured or
relocated.
- system board
- The primary circuit board in a PC that contains most of the basic
components of the system. Also referred to as motherboard or planar.
T
- TAPI
- Acronym for telephony application program interface. A set of
calls that allows applications to control modems and telephones
by routing application function calls to the appropriate "service
provider" DLL for a modem.
- tuple
- A data structure defined by the PCMCIA to describe a single, specific
characteristic of a PC Card. Tuples are chained together to form
the card information structure (CIS), which describes to system
software the PC Card's resource requirements and other characteristics.
Tuples consist of a tuple code, an offset to the next tuple, and
a number of bytes specific to the tuple.
U
- UART
- Acronym for universal asynchronous receiver-transmitter. A module
composed of a single integrated circuit that contains both the
receiving and transmitting circuits required for asynchronous
serial communication.
- Unimodem
- Name used to refer to the Windows universal modem driver. It is
a driver-level component that uses modem description files (INFs)
to control its interaction with the communications driver.
- Universal Serial Bus
- A bidirectional, isochronous, dynamically attachable serial interface
for adding peripheral devices such as game controllers, serial
and parallel ports, and input devices on a single bus.
- USB
- Acronym for Universal Serial Bus.
V
- VESA
- Acronym for Video Electronics Standards Association.
- VxD
- A device driver that runs at the privileged ring 0 protected mode
of the microprocessor. These drivers can extend the services of
the Windows kernel, supervise hardware operations, or perform
both functions. Such driver files are usually named according
to the scheme VxD, where x refers to the device or service supported.
W
- warm docking
- A system design to support removing or installing a mobile system
in a docking station while in a reduced power state such as suspend.
- Win32 API
- A 32-bit application programming interface for both Windows 95
and Windows NT that includes sophisticated operating system capabilities,
security, and API routines for Win32-based applications.
- workstation
- In general, a powerful computer having considerable calculating
and graphics capability.