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Seagate Ultra 320, Ultra 160 manual Glossary, Scsi client-server model

Models: Ultra 320 Ultra 160

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Application

Client

Initiator

Device Service Request

Device Service Response

Task Management Request Task Management Response

Logical

Unit

Device Server

Task

Manager

Target

Figure 2. SCSI client-server model

1.2.1Glossary

aborted command—A SCSI command that has been ended by aborting the task created to execute it.

ACA—Auto Contingent Allegiance (see below).

additional sense code—a combination of the ADDITIONAL SENSE CODE and ADDITONAL SENSE CODE QUALIFIER in the sense data (see SPC-4)

application client—An object that is the source of SCSI commands. An object in this sense is not a tangible piece of hardware, but may be a single numeric parameter, such as a logical unit number, or a complex entity that performs a set of operations or services on behalf of another object (see ANSI SAM-4, T10/1683-D).

asynchronous event notification—A procedure used by targets to notify initiators of events that occur when a pending task does not exist for that initiator.

asynchronous transfer—An information transfer that uses the REQ/ACK handshake with an offset of zero.

auto contingent allegiance (ACA)—One of the conditions of a task set following the return of a CHECK CONDITION status. See Section 4.4.2.

blocked task state—The state of a task that is prevented from completing due to an ACA condition.

blocking boundary—A task set boundary denoting a set of conditions that inhibit tasks outside the boundary from entering the Enabled state.

byte—An 8-bit construct.

call—The act of invoking a procedure.

client-server—A relationship established between a pair of distributed objects where one (the client) requests the other (the server) to perform some operation or unit of work on the client’s behalf (see SAM-4).

client—An object that requests a service from a server.

command—A request describing a unit of work to be performed by a device server.

4	Parallel SCSI Interface Product Manual, Rev. A

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Seagate Ultra 320, Ultra 160 manual Glossary, Scsi client-server model

Contents

Parallel Scsi Interface Page Parallel Scsi Interface Page Revision status summary sheet Revision Date Writer/EngineerParallel Scsi Interface Product Manual, Rev. a Table of Contents Parallel Scsi Interface Product Manual, Rev. a Logical characteristics Wide transferMessage system specification Miscellaneous Scsi bus characteristics Scsi commandsSPI information units Drive features List of Figures Xii Parallel Scsi Interface Product Manual, Rev. a How to use this interface manual Interface requirementsScope of Scsi standards General interface description Applicable standardsGlossary Scsi client-server modelPage Page Page Page Page Page Keywords Physical interface characteristics Summary of Scsi messagesMessage Name Hex Code Number Scsi bus Scsi IDs and associated Scsi bus arbitration priorities PriorityScsi bus signals overview Pcrc signal usage requirements Scsi target usage of PcrcaSE signals Signal statesSignal values LVD signalsOR-tied signals Voltage and current definitionsData bit P cable Data bit a cable I/O DB15-8 Scsi bus phase Signal sourcesSignal sources DB7-0Timing Scsi bus timingScsi bus control timing values in nanoseconds Reference Type Value ns Unless Timing descriptionNanoseconds unless otherwise noted Scsi bus data and information phase ST timing valuesTiming values for negotiated transfer rate Timing values for negotiated transfer rate in nanosecondsPage ATN transmit setup time Min Receive Scsi bus data and information phase DT timing values Total transmitter error budget Receiver errors Fast-160 Fast-320 CommentsInterconnect and system margin Crosstalk time shift ATN transmit setup timeATN receive setup time ISI of dataBus set delay Bus clear delayBus free delay Bus settle delayPCRC receive setup time Flow control receive setup timeFlow control transmit setup time PCRC transmit setup timePower on to selection Data release delayPhysical disconnection delay QAS arbitration delayReceive internal hold time Receive internal setup timeReceive setup time Receive negation periodReset to selection Reset delayReset hold time Residual skew errorStrobe offset tolerance System deskew delaySkew correction range System noise at launchMeasurement points Clocking methods for data transfers LVD measurement pointsST latching data vs. DT latching data Paced transfer on a Scsi bus DT synchronous transfer exampleSynchronous transfers Data transfer modesAsynchronous transfers Paced transfersData group transfers ST Data phase parallel transfersDT Data phase parallel transfers Information unit transfersNegotiation Negotiation algorithmNegotiable fields and effects of successful negotiation When to negotiateNegotiable fields Negotiation message pair Field nameResponding message requirements Response shall beField Name Message Numerically Transfer agreements Value Description Message Transfer rate Transfer period factorTransfer period factor relationships Synchronous12.6 REQ/ACK offset Transfer width exponentProtocol options Protocol options bitsIureq PPR negotiation setting Iureq to zero Bus phases resulting from Iureq changesSdtr negotiation PPR negotiation setting Iureq to one PPR negotiation keeping Iureq set to zeroRTI Retain Training Information WrflowRdstrm PcompenNegotiable field combinations TransferTransfer Period Message restrictions Negotiation message sequencesParallel Scsi Interface Product Manual, Rev. a Scsi bus phases overview BUS Free phaseUnexpected and expected bus free phases Expected bus free phases Arbitration and QAS overviewNormal Arbitration phase QAS phase overview QAS protocolSelection phase Information unit transfers disabled Information unit transfers enabledSelection overview Selection using attention condition timeout procedure Reselection phase Reselection phase overviewPhysical reconnection Physical reconnection timeout procedure Scsi bus fairnessInformation transfer phases Information transfer phasesSignal Phase Direction of transfer Comment Asynchronous transfer Synchronous transferST synchronous data transfer DT synchronous transfer Information unit transferPage Data group data field transfer Page Page Page Paced transfer Paced transfer training patternDT Data in phase training pattern Start of section aStart of section B DT Data OUT phase training pattern Start of section C3.2 P1 data valid/invalid state transitions Starting pacing transfers at end of training pattern Starting pacing transfers with no training patternEnding pacing transfers Paced information unit transferDeskewing Wide transferCommand phase Data phaseStatus phase Message phaseMessage OUT phase Signal restrictions between phasesMessage in phase exception condition handling Message OUT phase exception condition handlingScsi bus phase sequences Scsi bus phase sequences overviewHard reset or protocol error Reselection Selection Arbitration DT Data Message OUT Data bus protection ST data bus protection using parityParity checking rules for Selection and Reselection phases Data bus protection overviewError detection capabilities Order of bytes in the CRC fieldGeneral message protocols and formats Message formatsTwo-byte messages Message formatOne-byte messages Extended messagesMessage categories Extended Message CodesLink Control Messages Link Control message codes Key Identify message format DisconnectIdentify Bit ByteIgnore field definition Ignore Wide ResidueIgnore Wide Residue message format Invalid data bitsMessage Parity Error Initiator Detected ErrorLinked Command Complete Message RejectModify Data Pointer message format Modify Bidirectional Data PointerModify Bidirectional Data Pointer message format No OperationParallel Protocol Request Parallel Protocol Request message formatValue 00h 01h-FEh FFh Description Timing values Use ST Data in and ST Data OUT phases to transfer data Valid protocol options bit combinationsUse QAS for arbitration Parallel Protocol Request messages implied agreement Restore Pointers QAS RequestSave Data Pointers Synchronous Data Transfer Request Synchronous Data Transfer Request message formatSdtr messages implied agreements Target initiated Sdtr negotiation Initiator initiated Sdtr negotiationTask Complete Wide Data Transfer Request Wide Data Transfer Request message formatWdtr message implied agreement Target initiated Wdtr negotiationResponding Scsi device Wdtr response Implied agreement Task attribute messages Task attribute message overview and codesTask attribute message codes ACA Auto Contingent AllegianceACA message format Head of Queue OrderedAbort Task Task management messagesTask management message codes Task management message codes 0EhAbort Task SET Logical Unit ResetTarget Reset Clear ACAMiscellaneous Scsi bus characteristics Bus reset condition Hard resetReset events Asynchronous condition recoveryActive pointers Saved pointersCommand processing considerations and exception conditions Asynchronous event notificationIncorrect initiator connection Unexpected Reselection phase SPI information units Information unit transfer logical operationsPage Parallel Scsi Interface Product Manual, Rev. a 115 116 Parallel Scsi Interface Product Manual, Rev. a Parallel Scsi Interface Product Manual, Rev. a 117 SPI command information unit SPI information unitsSPI command information unit Bit Byte Task Attribute Codes Description Task Management flags Codes DescriptionSPI LQ information unit SPI LQ information unit Bit ByteBidi Direction F0H SPI LQ information unit typeCodes Type Description FFh AllPage SPI data information unit SPI data stream information unitSPI data information unit Bit Byte SPI status data stream information unit Bit Byte SPI status information unit SPI status information unit Bit ByteReserved Reserved for FCP Packetized Failures code Codes Description SPI command information unit fields invalidPacketized Failures field Bit Byte Task management function not supportedPage 130 Parallel Scsi Interface Product Manual, Rev. a Command implementation requirements Command Descriptor Block CDBReserved Page Fixed and variable length Command Descriptor Block formats Typical CDB for 12-byte commands Bit Byte Typical CDB for 16-byte commands Bit ByteAdditional CDB Data if required Typical variable length CDB Bit Byte Operation Code 7Fh Additional CDB Length n-7Page Control field Bit Byte Last Naca aLink b Status Status precedence Command examples Single command exampleDisconnect example Disconnect exampleTiming examples Auto Contingent Allegiance or Contingent AllegianceOverlapped commands Clearing an Auto Contingent Allegiance conditionIncorrect logical unit selection Sense dataAsynchronous Event Reporting Autosense Unit Attention condition Queued tasks formerly queued I/O processes Target hard resetLogical unit reset Untagged task queuingTagged task queuing Parameter rounding Programmable operating definitionIncorrect initiator connection Self-test operations Default self-testS.M.A.R.T. system Short and extended self-testsForeground mode Background modeSelf-test modes Exception commands for background self-tests Device type a Command Reference All device typesSelf-test mode summary Error detection for asynchronous information phasesProtection code Covered signals Word Location Signal MeaningPage Error detection properties Code descriptionProtection code usage Enabling protection code checking Error handlingProtection code transmission Disabling protection code checkingCase 1-Power off during removal or insertion SPI-3 to SCSI-2 terminology mapping SPI-3 to SCSI-2 terminology mappingSPI-3 equivalent term SCSI-2 term Index Code value reserved Disconnect privilege 148 domain 5, 9 dormant Initiator 3, 6, 14, 131, 140 faulted Multidrop 7 multimode Page Scsi Page Wdtr 40 170 Parallel Scsi Interface Product Manual, Rev. a Page Seagate Technology LLC