Gang
scanning
Sequential scanning of
multiple originals using a previously defined exposure
setting for each.
GDMO
Guidelines for Definition of Managed Objects.
GFSK
Gaussian Frequency-shift Keying signal modulation.
GIF
Graphic Image File
Gigabyte (GB)
A unit of measure which represents a billion Bytes. The standard calculation for a byte is an 8-bit word framed by a start and a stop bit; that is, 10 bits to a byte. A Gigabyte therefore equals 10 billion bits.
Glass Master
The glass disc on which manufacturers record data as part of the first step in CD manufacturing (mastering). A laser beam recorder (LBR) is used to transfer data onto the glass disc which is coated with a photosensitive material (photoresist).
GMSK
Gaussian-filtered minimum-shift keying signal modulation.
GPIB-488 bus
It permits up to 15 devices, including a controller, to be daisy-chained by using IEEE-488 connectors. These connectors have two 24-pin interfaces, a male and a female (except the last, a "terminating" device). There are 16 active lines; these are divided into three activity classes: "controllers," "talkers," and "listeners." Thirty-two numerical address are available (#0...#31). They are assigned to each device based on its functional configuration.
Devices, connected to the GPIB bus, are of three classes, as follows: Of the 5 possible devices that can be termed as "controllers," because they regulate bus functions, only one can be active at any time. Control may be passed between such devices. Only one can be designated as a controller-in-charge, (CIC). If there is no designated control device, then there can only be one talker; a.k.a., Talk Only (TOL). All other devices are considered as Listen Only (LON).
Of the 10 possible devices that can be termed as "talkers," because they transmit through the bus to other devices, only one can be active at a time. Of the 10 possible devices that can be termed as "listeners," because they accept data from the bus. One or more may be active at the same time.
There are four interface control lines for use by these devices: Interface Clear (IFC), Service Request (SRQ), Remote Enable (REN), and End OR Identify (EOI). There are three data "handshaking" lines which may be used for either flow-control commands, or data. These lines are designated: Data Valid (DAV), No Data Accepted (NDAC), and Not Ready For Data (NRFD). Eight data-only lines are available; one for each of the eight bits per data byte. This parallel transmission is faster than serial, but the distance is much shorter .
Note: PC What's The Problem? includes signal assignments and functional troubleshooting suggestions.
GPS
Global Positioning System is used to determine accurately any physical location on the earth. Transmissions from the 24 GPS satellites provide the necessary coordinates for the calculation by a device with the requisite chip set.
Graphics Tablets
These data-entry devices are referenced as: Tablets.
Green Book
The standard which defines the specification for CD-i.
GROUP 1 FAX
The original low-speed analog type of facsimile equipment, transmitting a page in 4 to 6 minutes.
GROUP 2 "FAX" equipment
It provides digital transmissions at 3 pages per minute.
GROUP 3 FAX device
It provides digital transmissions at 1 page in 24 seconds. The newest FAX standard.
GROUP 4 FAX device
It offers 5-seconds-a-page transmissions, and for higher-quality images, an improved 400 by 400 dot resolution.
GSM
Global System for Mobile Communications.
GUI
Graphical User Interface replaced the nongraphical commandline interface with one composed of an onscreen desktop of windows, dialogboxes, pull-down menus, and icons which may be accessed by keyboard and/or mouse.
Half Duplex
Two way communications, but one direction at-a-time. The remote system waits for your system to complete its transmission before it can transmit back to your system. Some versions of this protocol, for better interaction between systems, provide a "turnaround character," which tells the other system: "I am done; your turn now." Also reference: Full Duplex and Asymmetrical Duplex.
HALT
Highly-accelerated Life Test.
HASS
Highly-accelerated Stress Screening.
HAST
Highly-accelerated Stress Test.
HBM
Human Body Model
HD
Harmonic Distortion
HD, -hd
Label indicates a high-density disk, cartridge or CD with a data storage capacity greater than the original specification; typically, double the capacity.
HDLC (High-level data link)
Refer to Synchronous Communications.
HDSL
Hyperspeed DSL, covered with other DSL service types.
HDTV
High-definition Television.
HF
High frequency (3 MHz to 30 MHz).
HFS
Hierarchical File System. The directory structure for Macintosh computers.
HH (or 2H or "Half" )
Half-height drive or bay within a computer case of similar size that is half the standard full size. This measurement is also referenced as 2H or "Half." Compare HH with: FH, 3H, and 4H.
hipot
High-potential
HPA
High-power Amplifier
High Sierra Format
The original format for organizing files and directories on CD-ROM. A revised version of this format known as ISO 9660 was later adopted by the International Standards Organization.
Hold Track State
When a CD-ROM device enters the hold track state the optical pick-up is maintained at an approximately constant position on the media. This allows a paused operation to be resumed without latency due to seeking. However, rotational latency may be incurred.
HSM
Hierarchial Storage Management.
HTML
Hypertext Markup Language.
HTTP
Hypertext Transfer Protocol.
HV
High Voltage
Hz
Hertz.
References are samples only. Each one is presented in greater detail in the
Technical Research Assistant for 2001
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