Partial hit | Fujitsu MHT2060BH, MHT2040BH, MHT2080BH specs

6.4 Read-ahead Cache

6.4.3.4 Partial hit

In this situation, a part of read requested data including the top sector is stored in the data buffer. A transfer of the read requested data starts from the address where the data that is hit is stored until the top sector of the read requested data. Remaining part of insufficient data is read then.

An example is a case where a partial hit occurs in cache data, as shown below.

Cache valid data

TART LBA			LAST LBA

1)HAP is set at the address where partial hit data is stored, and Transfer is started.

HAP (host address pointer)

Cache valid data

Partial hit data

2)DAP and HAP are set at the head of Buffer newly allocated, and insufficient data is read.

HAP (host address pointer)

Read segment

DAP (disk address pointer)

3)When reading the read requested data ends and the transmission of the read requested data to the host system ends, the read-ahead operation continues until a certain amount of data is stored.

The method of storing the read-ahead data at Partial hit is the same as the Miss hit.

Cache valid data

LAST LBA START LBA

C141-E203-01EN

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Fujitsu MHT2060BH, MHT2040BH, MHT2080BH manual Partial hit

Contents

Disk Drives Product Manual MHT2080BH, MHT2060BH, MHT2040BH Handling of This Manual For Safe Operation Revision History This page is intentionally left blank Overview of Manual Preface Conventions for Alert Messages Operating EnvironmentConventions Liability Exception This page is intentionally left blank Important Alert Messages Important Alert Items This page is intentionally left blank MHT2040BH Disk Drives Maintenance Manual Manual OrganizationMHT2040BH Disk Drives Product Manual This page is intentionally left blank Contents Theory of Device Operation Installation Conditions Interface 102 Operations GL-1 Acronyms and Abbreviations AB-1IN-1 Figures Illustrations Response to power-on when the host is powered Tables Recommended connector specifications for the host system Relationship between combination of Identifier and Security Device Overview Features Functions and performanceAdaptability Interface MHT2080BH MHT2060BH MHT2040BH Device SpecificationsSpecifications summary Specifications 1/2 Examples of model names and product numbers Specifications 2/2Model and product number MHT2080BH Power Requirements Input VoltageRipple Current and power dissipation Current Requirements and Power Dissipation Environmental specifications Environmental SpecificationsCurrent fluctuation Typ. at +5 V when power is turned on Power on/off sequence Shock and Vibration Acoustic noise specificationShock and vibration specification Acoustic Noise Mean time between failures Mtbf Service lifeData assurance in the event of power failure Reliability Media Defects Error RateUnrecoverable read error Positioning error Advanced Power Management Advanced power management Interface Power Management IPM Host-initiated Interface Power Management HipmDevice-initiated Interface Power Management Dipm Interface power management This page is intentionally left blank Device Configuration Device Configuration Read/write circuit System ConfigurationSata interface Drive connection This page is intentionally left blank Installation Conditions Dimensions Dimensions Mounting Integration Guidance C141-E144Orientation Frame Limitation of mountingPCA Location of breather Ambient temperature Handling cautions Service area ESD Sumitomo 3MHios Connections with Host System Device connector Connector specifications for host system Signal segment and power supply segmentRecommended connector specifications for the host system Sata interface cable connection This page is intentionally left blank Theory of Device Operation Spindle OutlineSubassemblies Disk Spindle motor driver circuit Circuit ConfigurationAir filter Servo circuit Power Supply Configuration PCA Power-on operation sequence Power-on Sequence Self-calibration Self-calibration contents Execution timing of self-calibration Command processing during self-calibration RLL code Meeprml Read/write CircuitRead/write preamplifier PreAMP Write circuit Read circuit AGC circuitProgrammable filter circuit Viterbi detection circuit Digital PLL circuitFIR circuit D converter circuit Servo Control Servo control circuitMicroprocessor unit MPU Spindle motor control circuit Power amplifierServo burst capture circuit A converter DAC Outer guard band OGB Data-surface servo formatInner guard band IGB Data area Physical sector servo configuration on disk surface Servo frame format Track-following operation Actuator motor controlOperation to move the head to the reference cylinder Seek operation Start mode Acceleration modeSpindle motor control Stable rotation mode This page is intentionally left blank Interface Physical Interface Interface signals Comreset / Cominit Comwake5VDC/GND Out of band signaling Signal interface regulation Primitives descriptions Physical Layer Electrical Requirements 1/2 Electrical specifications COMRESET/C Physical Layer Electrical Requirements 2/2Ominit Connector pinouts Connector pinouts Logical Interface Conceptual diagram of communication layers Transport layer Communication layersPhysical layer Link layer Shadow Block Register Outline of the Shadow Block Register Register Host to Device FIS layout Outline of the frame information structure FISFIS types Register Host to Device DMA Active Device to Host Register Device to Host TAG DMA Setup Device to Host or Host to Device Bidirectional Bist combinations Bist Active Bidirectional Data FIS Bidirectional layout Data Host to Device or Device to Host Bidirectional Error Field Shadow block registersUNC Cylinder Low Field exp Features Field expSector Count Field exp Sector Number Field exp HS3 Cylinder High Field expDevice/Head Field HS3 HS2 HS1 HS0 Bit 7 Busy BSY bit Bit Device Write Fault DF bitBit Error ERR bit Status field EStatus Field Command FieldBit 2 Software Reset Srst Device Control Field Host Commands Command code and parametersCommand code and parameters 1/3 Command code and parameters 2/3 Command code and parameters 3/3 Command descriptions Recalibrate X’10’ to X’1F’ Error reporting conditions Read Sectors X’20’ or X’21’ LBA LBA LSB Read Long X’22’ or X’23’ Write Sectors X’30’ or X’31’ 00 *1 Error information Write Long X’32’ or X’33’ Cylinder No. LSB Write Verify X’3C’ Host Commands Read Verify Sectors X’40’ or X’41’ Host Commands Seek X’70’ to X’7F’ Diagnostic code Execute Device Diagnostic X’90’ Initialize Device Parameters X’91’ Operation of Download Microcode Download Microcode X’92’ Error reporting conditions Standby Immediate X’94’ or X’E0’ Idle Immediate X’95’ or X’E1’ Standby X’96’ or X’E2’ Idle X’97’ or X’E3’ Host Commands ’FF’ Check Power Mode X’98’ or X’E5’ Sleep X’99’ or X’E6’ Comreset Smart X’B0’ Features Field values subcommands and functions 1/3 Smart Read LOG Features Field values subcommands and functions 2/3Smart Enable Operations Smart Disable Operations Features Field values subcommands and functions 3/3 ’DB’ Smart ENABLE/DISABLE Auto OFF-LINESmart Return Status Key C2h 11 Format of guarantee failure threshold value data 10 Format of device attribute value data1FF Attribute ID Data format version number Raw attribute value Status FlagCurrent attribute value Attribute value for the worst case so far 12 Off-line data collection status Self-test execution status13 Self-test execution status 16 Drive error logging capability 14 Off-line data collection capability15 Failure prediction capability flag 17 Log Directory Data Format Guarantee failure thresholdSmart error logging Checksum 18 Data format of Smart Summary Error Log 1/2 Total number of drive errors 18 Data format of Smart Summary Error Log 2/2Command data structure Error data structure Smart Self-Test 19 Data format of Smart Comprehensive Error Log Self-test index 20 Smart self-test log data format1FC Self-test number 21 Selective self-test log data structure Test SpanCurrent LBA under test Selective Self-test pending time min Feature Flags22 Selective self-test feature flags Current Span under test Device Configuration Identify Device Configuration XB1Device Configuration Restore Device Configuration Freeze Device Configuration Freeze Lock Features Field = C1h Device Configuration Restore Features Field = C0h Device Configuration SET Features Field = C3h Device Configuration Identify Features Field = C2h Word Value Content 23 Device Configuration Identify data structure Read Multiple X’C4’ Execution example of Read Multiple command LBA LSB Write Multiple X’C5’ At command issuance Shadow Block Registers setting contents SET Multiple Mode X’C6’ Host Commands Read DMA X’C8’ or X’C9’ LBA Write DMA X’CA’ or X’CB’ Host Commands Read Buffer X’E4’ Flush Cache X’E7’ Write Buffer X’E8’ Identify Device X’EC’ Identify Device DMA X’EE’ ’3FFF’ 24 Information to be read by Identify Device command 1/3 24 Information to be read by Identify Device command 2/3 24 Information to be read by Identify Device command 3/3 Interface Bit 0 Reserved C141-E203-01EN FIS Host Commands Word Bit Bit 0 1 = Supports the Mode C141-E203-01EN Interface 25 Features field values and settable modes 1/2 SET Features X’EF’ 25 Features field values and settable modes 2/2 Data Transfer Mode Advanced Power Management APM Automatic Acoustic Management AAM Serial ATA Functions 26 Contents of Security SET Password data Error reporting conditions When the master password is selected When the user password is selectedSecurity UNLOCKX’F2’ Host Commands Security Erase Prepare X’F3’ Security Erase Unit X’F4’ Security Freeze Lock X’F5’ Error reporting conditions 28 Contents of security password Error reporting conditions Lbalsb Read Native MAX Address X’F8’ SET MAX Address SET MAX X’F9’ SET MAX SET Password Features Field = 01h Password information SET MAX Lock Features Field = 02h SET MAX Unlock Features Field = 03h SET MAX Freeze Lock Features Field = 04h Read Sector S EXT X’24’ Description CL EXPSN EXP Read DMA EXT X’25’ Description Read Native MAX Address EXT X’27’ Read Multiple EXT X’29’ Read LOG EXT X2F CL EXP SN EXP 30 Tag field information 29 Data format of Read Log Ext log page 10h Write Sector S EXT X’34’ Description Write DMA EXT X’35’ Description SET MAX Address EXT X’37’ SET MAX LBA Write Multiple EXT X’39’ Write LOG EXT X3F Error information 132 C141-E203-01EN Read Verify Sector S EXT X’42’ Flush Cache EXT X’EA’ Write Multiple FUA EXT XCE Write DMA FUA EXT X3D Read FP DMA Queued Write FP DMA Queued Sfrw Sfrr Error posting31 Command code and parameters 1/2 Command Name 31 Command code and parameters 2/2 Command Protocol Non-data command protocolExecute Device Diagnostic Initialize Device Parameters Host PIO data-in command protocol Piosu Data PIO data-out command protocol Piosu 12 PIO data-out command protocol Read DMA EXT Identfy DMA DMA data-in command protocol Write DMA EXT FUA EXT DMA data-out command protocol Read FP DMA Queued Write FP DMA Queued Native Command Queuing protocol 15 Read FP DMA Queued command protocol 16 Write FP DMA Queued command protocol 17 Power-on sequence Power-on and Comreset 18 Comreset sequence Operations Response to power-on Reset and Diagnosis Reset and Diagnosis Response to Comreset Response to Comreset Response to a software reset Response to a software reset Active idle mode Power SavePower save mode Active mode Sleep mode Standby mode Power commands Interface Power Save Power save mode of the interfacePartial mode Slumber mode Read-ahead Cache Data buffer structure8MB buffer Commands that are targets of caching Caching operationData that is a target of caching Invalidating caching-target data Miss-hit Using the read segment buffer Full hit Sequential hit HAP end location of the previous read command Partial hit Invalidation of cached data Command that are targets of cachingWrite Cache Cache operation Enabling and disabling Status report in the event of an errorComreset and software reset response Cashing function when power supply is turned on This page is intentionally left blank Glossary Positioning Power save modeRotational delay PIO Programmed input-output Acronyms and Abbreviations This page is intentionally left blank Index Block diagram Index Device-initiated interface power Frame information structure FIS Moving head to reference cylinder .4-13 RLL algorithm run length limited Read Native MAX Address Sensing and compensating for IN-8 C141-E203-01EN Comment Form Disk Drives Product ManualJapan This page is intentionally left blank C141-E203-01EN This page is intentionally left blank