System Startup, Configuration, and Shutdown Reference Manual (32650-90892)

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partial backups on all other work days.
data communications The transmission of information from one computer or terminal
to another. It is sometimes shortened to datacom.
data communications and terminal subsystems The methodology used to connect all
asynchronous devices to a 900 Series HP 3000, except for the system console.
default A predefined value or condition that is assumed, and used by the operating
system if no other value or condition is specified.
device adapter A device that manages communications between the computer and a
peripheral device. It is the same as an I/O interface card.
device class A collection of devices that have some user-defined relation. The file system
supports a means of maintaining collections of devices but is cognizant of the relation only
for certain device class names.
device file A file associated with a non shareable device (a spool file). Input and output
spool files are identified by a number in the DFID (device file identification) column of the
SHOWIN and SHOWOUT command displays. A device file can also refer to any non-disk device,
such as $STDIN and $STDLIST, the default input and output device files for a terminal.
device independence A characteristic of the operating system that allows users to
selectively redirect input or output from a program, session, or job using the FILE
command without regard to the nature of the device. File equations created with the FILE
command are in effect only for the duration of the job or session in which they were
defined.
device subtype A number ranging from 0 to 15 that defines a specific device and its
associated software driver. There can be several device subtypes within one basic type. For
example, a graphics terminal and one without graphics capabilities can share the same
device type, but are assigned different subtype numbers.
device type A number that defines a type of device. For example, 0 represents a
moving-head disk and 16 is the device type number assigned to line printers.
diagnostician capability (DI Capability) A capability usually assigned only to the
Hewlett-Packard customer engineer (CE). It allows the CE to conduct certain CPU and
diagnostic tests.
directory A system table showing the group or account in which a file is located. A
directory may contain other information such as size of the file, its creation date, any
modification dates, file creator, or file security information.
DISCFREE A utility that supplies information about a system's unused disk space,
transient and permanent space, and the volume's total space capacity. The information is
supplied in either a histogram or a condensed format. Equivalent to the MPE V/E FREE5
utility.