Curtiss-Wright SCRAMNet+ SC150e, Справочник по аппаратуре

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GLOSSARY
Copyright 2007 Glossary 4 S SC150e HARDWARE REFERENCE
protocol violation
----------------A signal error at the physical layer (fiber or coax) resulting from noise
on the transmission lines or a result of hardware failure. This violation
can be any one of the following:
• Missing transition for two clock periods on either line
• Parity error
• Framing error
read cycle
--------------------------A DTB cycle used to transfer 1-, 2-, 3-, or 4-bytes from a slave to a
master. The cycle begins when the master broadcasts an address and an
address modifier. Each slave captures this address and address modifier,
and checks to see if it is to respond to the cycle. If so, it retrieves the data
from its internal storage, places it on the data bus, and acknowledges the
transfer. Then the master terminates the cycle.
read-modify-write cycle
--------A DTB cycle that is used to both read from, and write to, a slave's byte
location(s) without permitting any other master to access that location
during that cycle. This cycle is most useful in multi-processing systems
where certain memory locations are used to control access to certain
systems resources, for example, semaphore locations.
requester
---------------------------A functional module that resides on the same board as a master or
interrupt handler and requests use of the CTB whenever its master or
interrupt handler needs it.
retry
--------------------------------A hardware failure condition reported when the first attempt to send a
message around the network has resulted in some type of bit error. The
originating node will retransmit the message indefinitely until the
originating node receives it correctly. Valid only in error correction
mode (PLATINUM.)
retry time-out
---------------------A hardware failure condition reported when the first attempt to send a
message around the network is not received by the originating node
within the time out period specified in CSR5. The originating node will
retransmit the message indefinitely until the originating node receives it
correctly. Valid only in error correction mode (PLATINUM.)
rising edge
-------------------------The time during which a signal makes its transition from low to high.
Rx
-----------------------------------Abbreviation for receive or receiver.
SCSI
--------------------------------Refers to the American National Standard for Information Systems Small
Computer System Interface - 1 (X3.131-1986) or the ANSI Small
Computer System Interface - 2 (X3.131-1989). This standard defines
mechanical, electrical and functional requirements for attaching small
computers to each other and to intelligent peripheral devices.
shadow memory
------------------See Auxiliary Control RAM (ACR)
shared memory (SM)
-----------SCRAMNet memory physically located on the network board. This dual-
ported memory is accessible by the host and the network. A host WRITE
to shared memory results in a transmitted WRITE to all SCRAMNet
nodes at the same relative location.
shortword
-------------------------16 bits. Also referred to as halfword.
signal mnemonics
----------------Terms used to identify signal line events. (1) An asterisk following the
name of signals that are level-significant denotes the signal is true/valid
when the signal is low. (2) A asterisk following the name of signals that
are edge-significant denotes the actions initiated by that signal occur on
the falling edge.