IBM 3592 Maintenance Information page 327

hard address
A physical address that is assigned through arbitration to the fibre card by the loop initialization
sequence.
hertz (Hz)
A unit of frequency equal to one cycle per second. In the US, line frequency is 60 Hz, or a change in
voltage polarity 120 times per second. In Europe, line frequency is 50 Hz, or a change in voltage
polarity 100 times per second.
hex
Hexadecimal.
Hexagonal-shaped fastener heads and tools.
homologation
Officially sanctioned, approved, ratified, confirmed, or certified.
In IBM terms, homologation is a process that is followed for some products from design start to
country regulator authorization that is followed to market the product.
hot-pluggable
Capability of a component to be removed or installed while power is still applied to the product,
without electrically damaging that component or affecting the remainder of the product. The
customer's operations are not interrupted because the library does not need to be powered off during
service activities.
HSARS
Hardware statistical analysis and reporting system.
This information about hardware is placed in non-volatile storage inside the drive. Contrast with
VSARS for media (tape).
HVD
High-voltage differential.
A description of a drive type.
HyperTerminal
Terminal emulator that you can run from your notebook.
Hz
Hertz.
I
IBG
Interblock gap.
IBMLZ1
The improved compression algorithm, which furnishes hardware execution efficiency by using as few
machine cycles as possible to compress or decompress a byte. The algorithm achieves good coding
efficiency for broad applications and provides data compression with less performance loss.
ID
identifier.
identifier (ID)
In programming languages, a logical unit that names a language object; for example, the names of
variables, arrays, records, labels, or procedures. An identifier usually consists of a letter that is
optionally followed by letters, digits, or other characters.
One or more characters that are used to identify or name data element and possibly to indicate
certain properties of that data element.
A sequence of bits or characters that identifies a program, device, or system to another program,
device, or system.
IDRC
Improved data recording capability.
IML
Initial microprogram load.
Glossary 307