Seagate ST39205LW/LC manual Scsi interface physical description, Scsi interface cable requirements

Page 70

60

Cheetah 36XL Product Manual, Rev. E

9.6.2SCSI interface physical description

The drive models described by this product manual support the physical interface requirements of the Ultra160 SCSI Parallel Interface-3 (SPI-3) standards as defined in American National Standard document X3T10/1302D revision 14, and operate compatibly at the interface with devices that support earlier SCSI-2 and SCSI-3 stan- dards. It should be noted that this is only true if the systems engineering has been correctly done, and if earlier SCSI-2 and SCSI-3 devices respond in an acceptable manner (per applicable SCSI Standards) to reject newer Ultra160 SCSI protocol extensions that they don’t support.

The drives documented in this manual support single-ended and low voltage differential physical interconnects (hereafter referred to as SE and LVD, respectively) as described in the ANSI SPI-3 standard. These drives implement driver and receiver circuits that can operate either SE or LVD. However, they cannot switch dynami- cally between SE and LVD operation.

The drives typically operate on a daisy-chain interface in which other SCSI devices are also operating. Devices on the daisy chain must all operate in the same mode, either SE or LVD, but not a mixture of these. On the interface daisy chain, all signals are common between all devices on the chain, or bus, as it is also called. This daisy chain of SCSI devices must be terminated at both ends with the proper impedance in order to operate correctly. Do not terminate intermediate SCSI devices. In some cases, the SCSI devices at each end have onboard termination circuits that can be enabled by installation of a jumper plug (TE) on the device. These ter- mination circuits receive power from either a source internal to the device, or from a line in the interface cable specifically powered for that purpose. LC and LW model drives do not have onboard termination circuits. Some type of external termination circuits must be provided for these drives by the end user or designers of the equipment into which the drives will be integrated. See Standard X3T10/1302D, sections 6.4 and 6.5 for the maximum number of devices that can successfully operate at various interface transfer rates on SE and LVD daisy chains.

“LC” model drives plug into PCBA or bulkhead connectors in the host. They may be connected in a daisy-chain by the host backplane wiring or PCBA circuit runs that have adequate DC current carrying capacity to support the number of drives plugged into the PCBA or bulkhead connectors. A single 80-pin I/O connector cable can- not support the DC current needs of several drives, so no daisy chain cables beyond the bulkhead connectors should be used. A single drive connected via a cable to a host 80-pin I/O connector is not recommended.

Table 12 shows the interface transfer rates supported by the various drive models defined in this manual.

Table 12: Interface transfer rates supported

Interface type/

Maximum transfer rate

 

 

 

 

 

 

 

 

 

 

drive models

Asynchronous

Fast-5

Fast-10

Fast-20

Fast-40

Fast-80

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SE

ST336705

yes

yes

yes

yes

no

no

 

ST318405

 

 

 

 

 

 

 

ST39205

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LVD

ST336705

yes

yes

yes

yes

yes

yes

 

ST318405

 

 

 

 

 

 

 

ST39205

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9.6.3SCSI interface cable requirements

The characteristics of cables used to connect Ultra160 SCSI parallel interface devices are discussed in detail in section 6 of ANSI Standard X3T10/1302D. The cable characteristics that must be considered when intercon- necting the drives described in this manual in a Ultra160 SCSI parallel, daisy-chain interconnected system are:

•characteristic impedance (see Section 6.1)

•propagation delay (see Section 6.1)

•cumulative length (see Sections 6.4 and 6.5)

•stub length (see Sections 6.4 and 6.5)

•device spacing (see Sections 6.4 and 6.5)

Page 69 Page 71
Image 70
Page 69 Page 71
Contents Cheetah 36XL Family ST336705LW/LC ST318405LW/LC ST39205LW/LC Page Cheetah 36XL Family ST336705LW/LC ST318405LW/LC ST39205LW/LC Page Revision status summary sheet Revision Date Writer/Engineer Sheets AffectedPage Contents Seagate Technology support services Defect and error managementInstallation Interface requirementsList of Figures Cheetah 36XL Product Manual, Rev. E ViiPage Scope Cheetah 36XL family drive ST336705LC shownCheetah 36XL Product Manual, Rev. E Applicable standards and reference documentation Korean MIC Australian C-TickTaiwanese Bsmi General description Cheetah 36XL family drive Performance Cheetah 36XL Product Manual, Rev. E Standard featuresMedia characteristics ReliabilityFormatted capacities Factory installed accessoriesOptions factory installed Programmable drive capacityPerformance characteristics Start/stop time Ultra2 Scsi Ultra160 ScsiPrefetch/multi-segmented cache control Cache operation Caching write dataPrefetch operation Cheetah 36XL Product Manual, Rev. E Cheetah 36XL Product Manual, Rev. E Reliability specifications Service life Reliability and servicePreventive maintenance Service philosophy7 S.M.A.R.T Controlling S.M.A.R.TDetermining rate Performance impactReporting control Predictive failuresImplementation State of the drive prior to testingDST Failure Definition Invoking DSTExtended test Function Code 010b Product warrantyShort test Function Code 001b Log page entriesProduct repair and return information Cheetah 36XL Product Manual, Rev. E AC power requirements Physical/electrical specificationsDC power requirements Conducted noise immunity Power sequencing3 12 V Current profile Typical ST336705 drive +12 V current profile Typical ST39205 drive +12 V current profile TypicalST318405 drive +5 V current profile Power dissipation ST336705 Cheetah 36XL Product Manual, Rev. E ST318405 Os per SecondST39205 TemperatureEnvironmental limits Shock and vibration Relative humidityEffective altitude sea level ShockPackage size Packaged/product weight Drop height Recommended mounting Vibration Air cleanlinessAcoustics LW mounting configuration dimensions LC mounting configuration dimensions Drive error recovery procedures Defect and error managementDrive internal defects Scsi systems errors Formatting InstallationConfigure drive options Drive ID/option select headerDo not install jumpers retain cover J5 jumper header on LW model only J2 option select header Cheetah 36XL Product Manual, Rev. E Function description Does not apply to LC modelsDrive mounting Drive orientationCooling GroundingInterface requirements Scsi interface messages supportedScsi interface commands supported Cheetah 36XL Product Manual, Rev. E Commands supported by Cheetah 36XL family drive Mode Sense data Inquiry Vital Product dataCheetah 36XL Product Manual, Rev. E Mode Sense Data Cheetah 36XL Product Manual, Rev. E Mode sense data, ST318405 values Bytes Cheetah 36XL Product Manual, Rev. E Mode sense data, ST39205 values Bytes Cheetah 36XL Product Manual, Rev. E Condition/features supported 2 REQ/ACK offset DC cable and connectorPhysical interface Pin Power Scsi interface physical description Scsi interface cable requirementsMating connectors for LC model drives Mating connectorsMating connectors for LW model drives ST336705LC, ST318405LC and ST39205LCRight-angle to Pcba connectors Scsi IDNonshielded 68 pin Scsi device connector used on LW drives Nonshielded 80 pin Scsi SCA-2 connector, used on LC drives GND +DBP1 Charge 68Cheetah 36XL Product Manual, Rev. E Electrical description Multimode signalsMultimode-SE and LVD alternatives Output characteristics Input characteristicsLow voltage differential I/O circuits General cable characteristicsTerminator requirements Terminator power LW drives LC drivesDisc drive Scsi timing Drive activity remote LED signal status Cheetah 36XL Product Manual, Rev. E Presales Support Seagate Technology support services Online ServicesAutomated Services Technical SupportUSA/Canada/Latin America Support Services Customer Service CSOEuropean Support Services Asia/Pacific Support Services Africa/Middle East Support ServicesCall Center Toll-free Direct dial Cheetah 36XL Product Manual, Rev. E Index Symbols Cheetah 36XL Product Manual, Rev. E LED PCB System chassis Page
Top Page Image Contents