Using the read segment buffer, Miss-hit | Fujitsu MHT2060BH manual

Operations

6.4.3 Using the read segment buffer

Methods of using the read segment buffer are explained for following situations.

6.4.3.1 Miss-hit

In this situations, the top block of read requested data is not stored at all in the data buffer. As a result, all of the read requested data is read from disk media.

1)HAP (host address pointer) and DAP (disk address pointer) are defined in the head of the segment allocated from Buffer. (If pre-read is executed, HAP is set at the requested data reading position.)

AP (host address pointer)

Read segment

DAP (disk address pointer)

2)During reading of read requested data, the request data that has already been read is sent to the host system.

HAP

Read requested data is stored until this point

Read requested data			Free space

DAP

3)When reading of read requested data is completed and transfer of the read requested data to the host system is completed, reading of the disk continues until a certain amount of data is stored.

HAP (stop)

Read requested data	Read-ahead data

DAP

4)The following cache valid data is for the read command that is executed next:

Cache valid data

LAST LBA START LBA

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Fujitsu MHT2060BH, MHT2040BH, MHT2080BH manual Using the read segment buffer, Miss-hit

Contents

MHT2080BH, MHT2060BH, MHT2040BH Disk Drives Product Manual For Safe Operation Handling of This Manual Revision History This page is intentionally left blank Preface Overview of Manual Conventions for Alert Messages Operating EnvironmentConventions Liability Exception This page is intentionally left blank Important Alert Items Important Alert Messages This page is intentionally left blank MHT2040BH Disk Drives Maintenance Manual Manual OrganizationMHT2040BH Disk Drives Product Manual This page is intentionally left blank Contents Installation Conditions Theory of Device Operation Interface 102 Operations GL-1 Acronyms and Abbreviations AB-1IN-1 Illustrations Figures Response to power-on when the host is powered Recommended connector specifications for the host system Tables Relationship between combination of Identifier and Security Device Overview Features Functions and performanceAdaptability Interface Device Specifications Specifications summarySpecifications 1/2 MHT2080BH MHT2060BH MHT2040BH Specifications 2/2 Model and product numberMHT2080BH Examples of model names and product numbers Power Requirements Input VoltageRipple Current Requirements and Power Dissipation Current and power dissipation Environmental Specifications Current fluctuation Typ. at +5 V when power is turned onPower on/off sequence Environmental specifications Acoustic noise specification Shock and vibration specificationAcoustic Noise Shock and Vibration Service life Data assurance in the event of power failureReliability Mean time between failures Mtbf Error Rate Unrecoverable read errorPositioning error Media Defects 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 System Configuration Sata interfaceDrive connection Read/write circuit This page is intentionally left blank Installation Conditions Dimensions Dimensions Mounting Integration Guidance C141-E144Orientation Frame Limitation of mountingPCA Location of breather Ambient temperature Service area Handling cautions ESD Sumitomo 3MHios Device connector Connections with Host System 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 Outline SubassembliesDisk Spindle Circuit Configuration Air filterServo circuit Spindle motor driver circuit Power Supply Configuration PCA Power-on Sequence Power-on operation sequence Self-calibration contents Self-calibration Command processing during self-calibration Execution timing of self-calibration Read/write Circuit Read/write preamplifier PreAMPWrite circuit RLL code Meeprml Read circuit AGC circuitProgrammable filter circuit Digital PLL circuit FIR circuitD converter circuit Viterbi detection circuit Servo Control Servo control circuitMicroprocessor unit MPU Power amplifier Servo burst capture circuitA converter DAC Spindle motor control circuit Data-surface servo format Inner guard band IGBData area Outer guard band OGB Physical sector servo configuration on disk surface Servo frame format Actuator motor control Operation to move the head to the reference cylinderSeek operation Track-following operation Start mode Acceleration modeSpindle motor control Stable rotation mode This page is intentionally left blank Interface Interface signals Physical Interface Comreset / Cominit Comwake5VDC/GND Signal interface regulation Out of band signaling Primitives descriptions Electrical specifications Physical Layer Electrical Requirements 1/2 COMRESET/C Physical Layer Electrical Requirements 2/2Ominit Connector pinouts Connector pinouts Conceptual diagram of communication layers Logical Interface Communication layers Physical layerLink layer Transport layer Outline of the Shadow Block Register Shadow Block Register Outline of the frame information structure FIS FIS typesRegister Host to Device Register Host to Device FIS layout Register Device to Host DMA Active Device to Host DMA Setup Device to Host or Host to Device Bidirectional TAG Bist Active Bidirectional Bist combinations Data Host to Device or Device to Host Bidirectional Data FIS Bidirectional layout Error Field Shadow block registersUNC Features Field exp Sector Count Field expSector Number Field exp Cylinder Low Field exp Cylinder High Field exp Device/Head FieldHS3 HS2 HS1 HS0 HS3 Bit Device Write Fault DF bit Bit Error ERR bitStatus field Bit 7 Busy BSY bit Command Field Bit 2 Software Reset SrstDevice Control Field EStatus 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 Error reporting conditions Recalibrate X’10’ to X’1F’ Read Sectors X’20’ or X’21’ LBA LSB LBA 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’ Execute Device Diagnostic X’90’ Diagnostic code Initialize Device Parameters X’91’ Download Microcode X’92’ Operation of Download Microcode 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 Check Power Mode X’98’ or X’E5’ ’FF’ Comreset Sleep X’99’ or X’E6’ Smart X’B0’ Features Field values subcommands and functions 1/3 Features Field values subcommands and functions 2/3 Smart Enable OperationsSmart Disable Operations Smart Read LOG 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 Data format version number Attribute ID Status Flag Current attribute valueAttribute value for the worst case so far Raw attribute value 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 Guarantee failure threshold Smart error loggingChecksum 17 Log Directory Data Format 18 Data format of Smart Summary Error Log 1/2 18 Data format of Smart Summary Error Log 2/2 Command data structureError data structure Total number of drive errors 19 Data format of Smart Comprehensive Error Log Smart Self-Test 20 Smart self-test log data format 1FCSelf-test number Self-test index 21 Selective self-test log data structure Test SpanCurrent LBA under test Feature Flags 22 Selective self-test feature flagsCurrent Span under test Selective Self-test pending time min Device Configuration XB1 Device Configuration RestoreDevice Configuration Freeze Device Configuration Identify Device Configuration Restore Features Field = C0h Device Configuration Freeze Lock Features Field = C1h Device Configuration Identify Features Field = C2h Device Configuration SET Features Field = C3h 23 Device Configuration Identify data structure Word Value Content 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’ 24 Information to be read by Identify Device command 1/3 ’3FFF’ 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 SET Features X’EF’ 25 Features field values and settable modes 1/2 25 Features field values and settable modes 2/2 Data Transfer Mode Advanced Power Management APM Serial ATA Functions Automatic Acoustic Management AAM 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 Read Native MAX Address X’F8’ Lbalsb SET MAX X’F9’ SET MAX Address 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 29 Data format of Read Log Ext log page 10h 30 Tag field information 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 Error posting 31 Command code and parameters 1/2Command Name Sfrw Sfrr 31 Command code and parameters 2/2 Command Protocol Non-data command protocolExecute Device Diagnostic Initialize Device Parameters Host PIO data-in command protocol PIO data-out command protocol Piosu Data 12 PIO data-out command protocol Piosu DMA data-in command protocol Read DMA EXT Identfy DMA DMA data-out command protocol Write DMA EXT FUA EXT Native Command Queuing protocol Read FP DMA Queued Write FP DMA Queued 15 Read FP DMA Queued command protocol 16 Write FP DMA Queued command protocol Power-on and Comreset 17 Power-on sequence 18 Comreset sequence Operations Reset and Diagnosis Response to power-on Reset and Diagnosis Response to Comreset Response to Comreset Response to a software reset Response to a software reset Power Save Power save modeActive mode Active idle mode Standby mode Sleep 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 Using the read segment buffer Miss-hit Sequential hit Full hit HAP end location of the previous read command Partial hit Command that are targets of caching Write CacheCache operation Invalidation of cached data Status report in the event of an error Comreset and software reset responseCashing function when power supply is turned on Enabling and disabling This page is intentionally left blank Glossary Power save mode Rotational delayPIO Programmed input-output Positioning Acronyms and Abbreviations This page is intentionally left blank Block diagram Index Index Device-initiated interface power Frame information structure FIS Moving head to reference cylinder .4-13 Read Native MAX Address RLL algorithm run length limited 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