Fujitsu MHC2040AT, MHC2032AT, MHD2021AT, MHD2032AT Read-ahead data New read-ahead data Hit data

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6.5 Read-Ahead Cache

b.Sequential hit

When the previously executed read command is the sequential command and the last sector address of the previous read command is sequential to the lead sector address of the received read command, the disk drive transfers the hit data in the buffer to the host system.

The disk drive performs the read-ahead operation of the new continuous data to the empty area that becomes vacant by data transfer at the same time as the disk drive starts transferring data to the host system.

1)In the case that the contents of buffer is as follows at receiving a read command;

HAP (Continued from the previous read request data)

Read-ahead data

Hit data

DAP

Last LBA Start LBA

2)The disk drive starts the read-ahead operation to the empty area that becomes vacant by data transfer at the same time as the disk drive starts transferring hit data.

HAP

Read-ahead data

New read-ahead data

Hit data

DAP

3)After completion of data transfer of hit data, the disk drive performs the read- ahead operation for the data area of which the disk drive transferred hit data.

HAP

Read-ahead data

DAP

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Contents MHC2032AT, MHC2040AT MHD2032AT, MHD2021AT Disk Drives Product ManualFor Safe Operation Handling of This ManualPage Revision History Page Preface Overview of ManualConventions for Alert Messages Operating EnvironmentLiability Exception Page Important Alert Items Important Alert MessagesPage Contents Contents Interface Contents GL-1 Illustrations FiguresTables Surface temperature measurement points and standard values Device Overview Features Functions and performanceAdaptability Features Specifications MHC2032AT/MHC2040AT Device SpecificationsSpecifications summary MHC2032AT MHC2040ATSpecifications MHD2021AT/MHD2032AT MHD2021AT MHD2032ATMHC2032AT Power RequirementsModel and product number MHD2021ATCurrent and power dissipation Current fluctuation Typ. at +5V when power is turned onAcoustic noise specification Environmental SpecificationsEnvironmental specifications Acoustic NoiseShock and Vibration Error Rate Media DefectsDevice Configuration Device Configuration Disk drive outerview the MHC Series and MHD SeriesConfiguration of disk media heads System Configuration ATA interface2 1 drive connection 2 drives configuration 3 2 drives connectionPage Installation Conditions Dimensions Dimensions MHC series 1/2Dimensions MHD series 2/2 Mounting Orientation Sample MHC2040ATPCA Mounting frame structureMeasurement point Temperature Service area Sample MHC2040AT Device connector Cable ConnectionsDevice connection Cable connector specificationsCable connector specifications BergJumper Settings Power supply connector CN1Location of setting jumpers Factory default setting Master drive-slave drive setting12 Csel setting 13 Example 1 of Cable Select14 Example 2 of Cable Select Page Theory of Device Operation Disk OutlineSubassemblies HeadSpindle ActuatorAir filter Circuit Configuration Circuit Configuration Power-on Sequence Self-calibration contents Self-calibrationExecution timing of self-calibration Read/write Circuit Command processing during self-calibrationSelf-calibration execution timechart Read/write preamplifier PreAMPWrite circuit Write precompensation algorithmRead/write circuit block diagram Frequency characteristic of programmable filter Read circuitDigital PLL circuit Servo Control Servo control circuitServo Control Physical sector servo configuration on disk surface Servo Control Data-surface servo format Servo frame formatActuator motor control Spindle motor control Servo Control Page Interface Interface signals Physical InterfaceSignal assignment on the connector Signal assignment on the interface connectorDasp GND Stop EncselDiow DiorDasp IordyDdmardy Logical Interface 1 I/O registers I/O registersDA2 DA1 DA0 Command block registers UNC Idnf AbrtLogical Interface DEV HS3 HS2 HS1 HS0 BSY DSC DRQ ERRInterface Host Commands Control block registersSrst Command code and parameters Command code and parameters 1Command code and parameters 2 Command descriptions Host Commands Read Multiple X’C4’ Host Commands Execution example of Read Multiple command Host Commands Interface End head No. /LBA MSB 1F7 HCM 1F6 HDH Write Multiple X’C5’ Interface Write Verify X’3C’ Interface Host Commands Initialize Device Parameters X’91’ Identify Device X’EC’ Information to be read by Identify Device command 1 Number of current Cylinders Information to be read by Identify Device command 2 Command Bit Reserved Multiple sector transfer =Enable Information to be read by Identify Device command 3 Identify Device DMA X’EE’ ’AA’ SET Features X’EF’Features register values and settable modes ’BB’Host Commands SET Multiple Mode X’C6’ Host Commands Execute Device Diagnostic X’90’ Diagnostic code Interface Host Commands Write Buffer X’E8’ Host Commands Interface Host Commands Interface Host Commands ’FF’ Host Commands Features Register values subcommands and functions Features Resister Function Format of device attribute value data 1FFFormat of insurance failure threshold value data Interface Host Commands Interface 10 Contents of security password At command issuance I-O register contents 1F7 hCM Host Commands Read DMA Write DMA 11 Contents of Security SET Password data Locked Mode Flush Cache E7 Error posting 13 Command code and parameters 113 Command code and parameters 2 Command Protocol Data transferring commands from device to hostExecute Device Diagnostic Initialize Device Parameters Read Sectors command protocol Data transferring commands from host to device Protocol for command abortWrite Sectors command protocol Commands without data transfer Other commands DMA data transfer commandsRead Multiple Sleep Write Multiple Normal DMA data transfer Ultra DMA Feature Set OverviewPhases of operation Ultra DMA burst initiation phaseData transfer phase Ultra DMA burst termination phaseUltra DMA data in commands Initiating an Ultra DMA data in burstPausing an Ultra DMA data in burst Data in transferTerminating an Ultra DMA data in burst Ultra DMA Feature Set Interface Ultra DMA data out commands Initiating an Ultra DMA data out burstData out transfer Pausing an Ultra DMA data out burst Terminating an Ultra DMA data out burst Interface Ultra DMA CRC rules XOR f11 Series termination required for Ultra DMA 15 Recommended series termination for Ultra DMATiming PIO data transfer10 Data transfer timing 11 Single word DMA data transfer timing mode Single word DMA data transfer12 Multiword DMA data transfer timing mode Multiword DMA data transferTransfer of Ultra DMA data Starting of Ultra DMA data In BurstName Mode Comment MIN MAX 16 Ultra DMA data burst timing requirements 2 DmardySustained Ultra DMA data in burst 14 Sustained Ultra DMA data in burstHost pausing an Ultra DMA data in burst 15 Host pausing an Ultra DMA data in burstDevice terminating an Ultra DMA data in burst 16 Device terminating an Ultra DMA data in burstHost terminating an Ultra DMA data in burst 17 Host terminating an Ultra DMA data in burst18 Initiating an Ultra DMA data out burst Sustained Ultra DMA data out burst 19 Sustained Ultra DMA data out burstDevice pausing an Ultra DMA data out burst 20 Device pausing an Ultra DMA data out burstHost terminating an Ultra DMA data out burst 21 Host terminating an Ultra DMA data out burst22 Device terminating an Ultra DMA data out burst Power-on and reset 23 Power on Reset TimingOperations Device Response to the Reset Response to power-onResponse to power-on Response to hardware reset Response to hardware resetResponse to software reset Response to software resetResponse to diagnostic command Response to diagnostic commandDefault parameters Default parametersAddress Translation Address translation example in CHS mode Logical addressPower Save Power save modeOperations Power commands Defect ManagementSpare area Alternating defective sectorsAlternate cylinder assignment Data buffer configuration Read-Ahead CacheCaching operation Read Sector S Read Multiple Read DMA − Write Sectors − Write DMA − Write Multiple− Read Sector S − Read DMA Usage of read segment Mis-hit no hitSequential read HAP DAPRead-ahead data New read-ahead data Hit data Full hit hit all Partially hit Write Cache Write Sectors Write Multiple Page Glossary PIO Programmed input-output Power save modeRotational delay PositioningStatus VCMPage Acronyms and Abbreviations Page Index Index DACInitialize Device Parameters MPU Mtbf Mttr Read DMA Read Long 5-43 Read Multiple 5-18 Read SectorsSET Features IN-6 C141-E050-02EN Page Drives Product Manual Comment FormMHC2032AT, MHC2040AT, MHD2032AT, MHD2021AT Disk Japan

MHC2040AT, MHC2032AT, MHD2032AT, MHD2021AT specifications

Fujitsu offers a range of advanced hard disk drives (HDD) designed for various computing needs, including the MHD2021AT, MHD2032AT, MHC2032AT, and MHC2040AT models. These drives combine reliable performance, capacity options, and technological features aimed at enhancing data storage efficiency.

The Fujitsu MHD2021AT is known for its capacity of 20 GB, making it an excellent choice for users requiring a compact and efficient HDD. With a spindle speed of 5400 RPM, it balances speed and power consumption, catering to mobile computing and lower power devices. Its ATA interface ensures compatibility with a wide range of systems, making it a versatile option for various applications.

The MHD2032AT model offers a slightly higher capacity of 30 GB, maintaining similar technological attributes to its predecessor. With an enhanced data transfer rate, it allows for quicker access to stored files, perfect for users handling larger volumes of data. The robust error correction features in this model further ensure data integrity, making it a reliable choice for demanding environments.

For users needing more robust storage solutions, the MHC2032AT steps it up with features tailored for performance-heavy applications. Its 30 GB capacity is suited for desktop and workstation environments that require swift data retrieval and significant storage. The drive employs advanced caching techniques, which boost performance further by optimizing read and write operations, ensuring smoother multitasking capabilities.

The MHC2040AT is the flagship model in this line, providing an impressive storage capacity of 40 GB. This HDD is designed for high-performance applications where speed is crucial. The drive’s increased spindle speed and superior data transfer rates make it ideal for video editing, gaming, and large database management. Alongside its enhanced performance features, it includes advanced thermal management technology that maintains optimal operational temperatures, prolonging the drive's lifespan.

All four models leverage Fujitsu's commitment to data reliability, featuring robust shock resistance and low noise levels. Collectively, these drives cater to a spectrum of user needs, from compact data storage to high-capacity solutions, maintaining Fujitsu's reputation for quality and innovation in the storage market.
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