LSI 40909G-S User Manual
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3.75 pc
10.25 pc
11.25 pc
38.25 pc
4.333 pc
48.583 pc
52.5 pc
34.5 pc
44.25 pc
Glossary of Terms and Abbreviations
A-5
Operating
System
A program that organizes the internal activities of the computer and its
peripheral devices. An operating system performs basic tasks such as
moving data to and from devices, and managing information in memory.
It also provides the user interface.
Operation
A term, defined in FC-2, that refers to one of the FC “building blocks”
composed of one or more, possibly concurrent, exchanges.
Ordered Set
An FC term referring to four 10-bit characters (a combination of data and
special characters) that provide low level link functions, such as frame
demarcation and signaling between two ends of a link. It provides for
initialization of the link after power-on and for some basic recovery
actions.
Originator
An FC term referring to the initiating device.
Parity Checking
A way to verify the accuracy of data transmitted over the SCSI bus. One
bit in the transfer is used to make the sum of all the 1 bits either odd or
even (for odd or even parity). If the sum is not correct, an error message
appears.
PCI
Peripheral Component Interconnect. A local bus specification that allows
connection of peripherals directly to computer memory. It bypasses the
slower ISA and EISA buses.
PDB
Packet Descriptor Block.
PIO
Programmed Input/Output. A way the CPU can transfer data to and from
memory using the computer’s I/O ports. PIO is usually faster than DMA,
but requires CPU time.
Port
The hardware entity within a node that performs data communications
over the FC link.
Port Address
Also Port Number. The address through which commands are sent to a
host adapter board. This address is assigned by the PCI bus.
Port Number
See Port Address.
RAM
Random Access Memory. The computer’s primary working memory in
which program instructions and data are stored and are accessible to the
CPU. Information can be written to and read from RAM. The contents of
RAM are lost when the computer is turned off.