iTP Active Transaction Pages (iTP ATP) Programmer's Guide

Glossary
iTP Active Transaction Pages (iTP ATP) Programmer’s Guide—522292-002
Glossary-5
physical layer
physical layer. Layer 1 in the OSI Reference Model. This layer establishes the actual
physical connection between the network and the computer equipment. Protocols at the
Physical Layer include rules for the transmission of bits across the physical medium and
rules for connectors and wiring.
process. A running entity that is managed by the operating system, as opposed to a program,
which is a collection of code and data. When a program is taken from a file on a disk
and run in a processor, the running entity is called a process.
protocol. A formal description of the message formats and rules two or more machines must
follow to exchange messages. Protocols can describe low-level details of machine-to-
machine interfaces (for example, the order in which the bits from a byte are sent across a
wire) or high-level exchanges between application programs (for example, the way in
which two programs transfer a file across the Internet). Most protocols include both
intuitive descriptions of the expected interactions and more formal specifications using
finite state-machine models.
QIO subsystem. A product that provides buffers and control blocks for protocol processes,
including TCP/IP, TLAM, and NonStop IPX/SPX running on the same processor.
Request for Comments (RFC). The name of a series of notes that contain surveys,
measurements, ideas, techniques, and observations, along with proposed and accepted
Internet protocol standards. RFCs are edited but not referenced. They are available
across the Internet.
RFC. See Request for Comments (RFC)
Secure Sockets Layer (SSL). A protocol for private communication on the World Wide Web
and authentication of a web server by a web client.
server. A process or set of processes that satisfy requests from web clients in a client-server
environment.
server class. A grouping of duplicate copies of a single server program, all of which execute
the same object program.
server process. A process that implements requests for an application and returns replies to
the requester.
server programs. In NonStop TS/MP, programs that handle the data manipulation and data
output activities for online transaction processing applications. Server programs are
designed to receive request messages from requester programs; perform the desired
operations, such as database inquiries or updates, security verifications, numerical
calculations, or data routing to other computer systems; and return reply messages to
requester programs.
Simple Mail Transfer Protocol (SMTP). The Internet standard protocol for transferring
e-mail messages from one machine to another. SMTP specifies how two mail systems
interact, and specifies the format of control messages the two mail systems exchange to
transfer mail.