Introduction to Networking for NonStop S-Series Servers

Introduction to Networking for HP NonStop S-Series Servers—520670-005
Glossary-1
Glossary
This glossary includes a selection of terms used in this manual. Definitions of data
communications terms are brief; they are intended only to make this manual more
meaningful than it would otherwise be to readers unfamiliar with communications and
networking. Many textbooks and technical dictionaries define these terms in more
detail.
access method. An input/output process (IOP) that allows applications running on a
NonStop server to communicate with other systems or devices. More generally, a
protocol that provides for orderly access, by systems and devices, to a
communications medium.
activity attribute. A dynamic attribute of a file, specific to an individual File Transfer,
Access, and Management (FTAM) association. See also file attribute.
AC transfer switch. A component that provides access to dual AC power sources and the
ability to switch between them if one source fails. The ServerNet II Switch and the
uninterruptible power supply (UPS) have only a single power input. To reduce the
likelihood that a single failure in an AC line source will bring down a ServerNet II
Switch, an AC transfer switch with two line cords is incorporated into the switch power
subsystem. The AC transfer switch draws power from its primary current source as
long as it is available. If the primary source fails, then the load is switched to the
secondary current source.
adapter. See ServerNet adapter.
ANSI. An acronym for American National Standards Institute.
API. See application program interface (API)
.
Application Layer. Layer 7 of the Open Systems Interconnection (OSI)
Reference Model.
This layer provides the interface between user programs (application processes) and
the OSI network. Layer 7 provides for peer-to-peer communication between
applications and includes standards for services such as file transfer and electronic
mail (e-mail).
application program interface (API). A set of functions or procedures that are called by an
application program to communicate with other software components.
ARPA. An acronym for Advanced Research Projects Agency.
asynchronous data transmission. A method of data transmission in which data is sent
and received one character at a time, each character being preceded by a start bit and
followed by one or more stop bits. Contrast with synchronous data transmission.
Note. Names of HP products are generally defined in Appendix A, HP NonStop
Communications Products, rather than in this glossary.