IBM 6400 Programmer's Reference Manual page 220

Glossary
3. In the IPDS architecture, a condition that requires
the host to resend data.
See also data-stream exception, asynchronous
exception, and synchronous exception.
exception action. Action taken when an exception is
detected.
exception condition. The condition that exists when a
product finds an invalid or unsupported construct.
exchange. The predictable interpretation of shared
information by a family of system processes in an
environment where the characteristics of each
process must be known to all other processes.
Contrast with interchange.
expanded. A type width that widens all characters of
a typeface.
Extended Binary-Coded Decimal Interchange Code
(EBCDIC). A coded character set that consists of
eight-bit coded characters.
extent. In FD:OCA, one of the characteristics of a
dimension. If all partitions of a dimension have the
same number of subpartitions, then this number is
called the extent of the next lower dimension. See
also local extent.
external leading. The amount of white space, in
addition to the internal leading, that can be added to
interline spacing without degrading the aesthetic
appearance of a font. This value is usually specified
by a font designer. Contrast with internal leading.
F
FGID. See Font Typeface Global Identifier.
fillet. A curved line drawn tangential to a specified
set of straight lines. An example of a fillet is the
concave junction formed where two lines meet.
FOCA. See Font Object Content Architecture.
font. A set of graphic characters that have a
characteristic design, or a font designer's concept of
how the graphic characters should appear. The
characteristic design specifies the characteristics of
its graphic characters. Examples of characteristics
are shape, graphic pattern, style, size, weight, and
increment. Examples of fonts are fully described
fonts, symbol sets, and their internal printer
representations. See also coded font and symbol set.
font character set. A FOCA resource containing
descriptive information, font metrics, and the digital
representation of character shapes for a specified
graphic character set.
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Font Typeface Global Identifier (FGID). A unique font
identifier that can be expressed as either a two-byte
binary or a five-digit decimal value. The FGID is used
to identify a type style and the following
characteristics: posture, weight, and width.
font height (FH). (1) A characteristic value,
perpendicular to the character baseline, that
represents the size of all graphic characters in a font.
Synonymous with vertical font size. (2) In a font
character set, nominal font height is a font-designer
defined value corresponding to the nominal distance
between adjacent baselines when character rotation
is zero degrees and no external leading is used. This
distance represents the baseline-to-baseline
increment that includes the font's maximum baseline
extent and the designer's recommendation for
internal leading. The font designer can also define a
minimum and a maximum vertical font size to
represent the limits of scaling. (3) In font
referencing, the specified font height is the desired
size of the font when the characters are presented. If
this size is different from the nominal vertical font
size specified in a font character set, the character
shapes and character metrics might need to be scaled
prior to presentation.
font index. (1) The mapping of a descriptive font
name to a font member name in a font library. An
example of a font member in a font library is a font
resource object. Examples of attributes used to form
a descriptive font name are typeface, family name,
point size, style, weight, and width. (2) In the IPDS
architecture, an LF1-type raster-font resource
containing character metrics for each code point of a
raster font or raster-font section for a particular font
inline sequence. There can be a font index for 0
degree, 90 degree, 180 degree, and 270 degree font
inline sequences. A font index can be downloaded to
a printer using the Load Font Index command. An
LF1-type coded font or coded-font section is the
combination of one fully described font and one font
index. See also fully described font.
font inline sequence. The clockwise rotation of the
inline direction relative to a character pattern.
font metrics. Measurement information that defines
individual character values such as height, width, and
space, as well as overall font values such as
averages and maximums. Font metrics can be
expressed in specific fixed units, such as pels, or in
relative units that are independent of both the
resolution and the size of the font. See also character
metrics and character set metrics.
font object. A resource object that contains some or
all of the description of a font.
Font Object Content Architecture (FOCA). An
architected collection of constructs used to describe
fonts and to interchange those font descriptions.