Technical data

GL–7
Compaq HSG80 Array Controller ACS Version 8.3 Maintenance and Service Guide
full duplex (n) A communications system in which there is a capability for 2-way
transmission and acceptance between two sites at the same time.
full duplex (adj) Pertaining to a communications method in which data can be transmitted
and received at the same time.
FWD SCSI A fast, wide, differential SCSI bus with a maximum 16-bit data transfer rate
of 20 MB/s. See also SCSI and FD SCSI.
giga A prefix indicating a billion (10
9
) units, as in gigabaud or gigabyte.
gigabaud An encoded bit transmission rate of one billion (10
9
) bits per second.
gigabyte A value normally associated with a disk drives storage capacity, meaning a
billion (10
9
) bytes. The decimal value 1024 is usually used for one
thousand.
half-duplex (adj) Pertaining to a communications system in which data can be either
transmitted or received but only in one direction at one time.
hard address The AL_PA which an NL_Port attempts to acquire during loop
initialization.
host The primary or controlling computer to which a storage subsystem is
attached.
host adapter A device that connects a host system to a SCSI bus. The host adapter
usually performs the lowest layers of the SCSI protocol. This function may
be logically and physically integrated into the host system.
host compatibility
mode
A setting used by the controller to provide optimal controller performance
with specific operating systems. This improves the controller’s performance
and compatibility with the specified operating system. The supported modes
are A, Normal (including DIGITAL UNIX
®
, OpenVMS, Sun
®
, and
Hewlett-Packard
®
HP–UX); B, IBM AIX
®
; C, Proprietary; and D,
Microsoft Windows NT
TM
Server.
hot disks A disk containing multiple hot spots. Hot disks occur when the workload is
poorly distributed across storage devices which prevents optimum
subsystem performance. See also hot spots.