NonStop System Glossary

empty string
In C and C++ programs, a character string that begins with a null character. This term is synonymous
with null string.
EMS
See Event Management Service (EMS).
EMS collector
An Event Management Service (EMS) process to which subsystems report events.
EMU
See environmental monitoring unit (EMU).
emulate
To imitate the instruction set and address spaces of a different hardware system by means of
software. Emulator software is compatible with and runs software built for the emulated system.
For example, a TNS/R or TNS/E system emulates the behavior of a TNS system when executing
interpreted or accelerated TNS object code.
emulation millicode
See TNS Emulation Library.
encapsulating security payload (ESP)
A dedicated TCP/IP extension header that provides data encapsulation with encryption to ensure
that only the destination node can read the payload conveyed by the IP packet. ESP may also
provide packet integrity and authenticity and an anti-replay service. ESP can be used alone or with
the authentication header to provide the desired security features for IP traffic. See also authentication
header (AH) and security association (SA).
enclosure
A single sheet-metal structure and its enclosed set of system components. See also base enclosure,
stackable enclosure, system enclosure and peripheral enclosure.
enclosure interleaving
Configuring a mirrored disk volume to use two separate system enclosures. For internal disk drives,
the two disk drives of the mirrored volume can be in separate enclosures. For external disk drives,
the adapters connected to the two disk drives of the mirrored volume can be in separate enclosures.
endian
Denotes the significance of byte 0 in a multibyte structure such as a word. NonStop servers are
big-endian, where the most significant bit is contained in byte 0. Intel systems and HP AlphaServer
OpenVMS and HP AlphaServer Tru64 UNIX systems are little-endian, where the least significant
bit is contained in byte 0.
enoft utility
A utility that reads and displays information from TNS/E native object files. See also noft utility.
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