trace. Arecord of the execution of a computer
program. It exhibits the sequences in which the
instructions were executed. (A)
TRC. Tablereference character.
tumble duplex printing. Duplex printing for sheets
that are to be bound on the short edge of the paper
regardless of whether the printing is portrait or
landscape. Contrast with normal duplex printing.
two-channel switch. Ahardware feature that allows
an I/O device to be attached to two channels.A
dynamic switch can be added, which allows both
interfaces to be enabled at the same time with channel
selection determined by programming.
type size. (1)A measurement in pitch or points of the
height and width of a graphic character in a font. (2)
One of the many attributes of a font; other attributes, for
example, are weight and width.
typeface. Acollection of fonts all having the same
style, weight, and width. Each font differs from the
others by point size or type family.
typographic font. Afont in which the distance
between characters varies. The distance from one
character to another is adjusted to improve the visual
flow of text by eliminating excess space.
U
UCS. Seeuniversal character set.
unbounded-box font. Afont designed to use
unbounded character boxes. Contrast with bounded-box
font.
unformatted print records. Line data made up of
fields of data that have not been formatted into print
lines. PSF uses a page definition to format these
records for printing on page printers.
uniformly spaced font. Afont in which the characters
have the same character increment. Contrast with
proportionally spaced font.
universal character set (UCS). Aprinter feature that
permits the use of a variety of character arrays.
UPA. Seeuser printable area.
user printable area (UPA). Thearea within the valid
printable area (VPA)where user-generated data can
print without causing an exception condition. See also
valid printable area.
V
valid printable area (VPA). Theintersection of a
logical page with the area of the medium presentation
space in which printing is allowed. If the logical page is
a secure overlay,the area in which printing is allowed is
the physical printable area. If the logical page is not a
secure overlay,and if a user printable area is defined,
the area in which printing is allowed is the intersection
of the physical printable area with the user printable
area. If a user printable area is not defined, the area in
which printing is allowed is the physical printable area.
See also logical page and user printable area.
value. Aquantity assigned to a constant, a variable, a
parameter,or a symbol in a command.
Virtual TelecommunicationsAccess Method
(VTAM). Aset of programs that maintains control of
the communication between terminals and application
programs running under DOS/VS, OS/VS1, and
OS/VS2 operating systems.
VPA. Seevalid printable area.
VTAM. VirtualTelecommunications Access Method.
W
wide forms. (1) Forms that have their longer edges at
the top and bottom and their shorter edges at the sides.
(2) Forms that have perforations on the longer edge of
the paper and tractor holes on the shorter edge.
X
XA. ExtendedArchitecture.
X-axis. In printing, an axis perpendicular to the
direction in which the paper moves through the printer.
See also Y-axis.
Y
Y-axis. Inprinting, an axis parallel with the direction in
which the paper moves through the printer.See also
X-axis.
206 Printer Information