MPE/iX Glossary of Terms and Acronyms (32650-90887)

Chapter 1 57
Glossary of Terms
is determined not to be a UDC nor an MPE command.
sector A portion of a track on a disk, and the smallest addressable piece of the
disk. MPE-formatted disks use 128-word sectors (256 bytes).
security 1. The provisions that prevent unauthorized users from entering the
system, accessing data, or using resources, programs, or capabilities.
2. The provisions included in MPE to protect the system from
unauthorized use. MPE offers several means to create a secure
environment. The most basic level of security includes organizing files
into groups and users into accounts, either of which may be assigned a
password. Security also refers to the ability to read, write, append, lock,
and execute files, optionally assigned to accounts by the system
manager and to groups and users by the account manager.
segmented library (SL) A file containing code segments that are shareable, general-use
MPE, utility, and subsystem procedures not unique to a particular process.
The three levels of segmented libraries are: LIB=G (group library), LIB=P
(public library), LIB=S (system library). G, P, and S refer to the location of
the CM program being run. If
program.group.account is run with
LIB=G, then SL.
group.account is used. If program.group.account is
run with LIB=P, then SL.PUB.
account is used. Otherwise, SL.PUB.SYS
(LIB=S) is used. The SL resolves external procedure calls not contained in
the program itself. The group SL is available to any user who can access
the group; the public SL is available to all account users; and the system
SL is available to all system users.
segmenter A subsystem of the MPE V/E operating system that performs all execution.
Its primary function is to gather and link into segments most of the
resources needed to form an executable program file.
self-clocking data The transmission of data when the clock information is part of the
data.
separator A symbol that separates the parameters of an instruction. Some examples
of separators are commas, spaces, and semicolons.
sequential The order (ascending or descending) in which data items are physically
stored and accessed.
serial See sequential.
serial disk A serially-accessed disk that is configured as a magnetic tape. Flexible
diskettes, disk packs, and cartridge tape (MPE V/E) may all be used as
serial disks. They are designed to store system data (backups), load
subsystems, and to perform standalone CPU and non-CPU diagnostics.
serial interface A single data line that transfers data bytes sequentially between
devices.
server A node unit of a network that provides a specific service to network users.
session A mode in which the HP 3000 is used interactively by entering commands
and data through a terminal's keyboard and receiving immediate
responses to input. A session is initiated with the HELLO command. A