Samsung M8 manual Firmware Features, Write Channel, Read Caching

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The Sequencer module identifies the data as belonging to the target sector. After a full sector is read, the

88i9322 (Rev2.0) checks to see if the firmware needs to apply an ECC algorithm to the data. The Buffer Control section of the 88i9322 (Rev2.0) stores the data in the cache and transmits the data to the AT bus.

5.4.2The Write Channel

The signal path for the Write Channel follows the reverse order of that for the Read Channel. The host transmits data via the AT bus to the 88i9322 (Rev2.0) Interface Controller. The Buffer Controller section of the 88i9322 (Rev2.0) stores the data in the cache. Because the data is transmitted to the drive at a rate that exceeds the rate at which the drive can write data to the disk, data is stored temporarily in the cache. Thus, the host can present data to the drive at a rate independent of the rate at which the drive can write data to the disk.

Upon correct identification of the target address, the data is shifted to the Sequencer, which generates and appends an error correcting code. The Sequencer then converts the bytes of data to a serial bit stream. The AT controller also generates a preamble field, inserts an address mark, and transmits the data to the ENDEC in the R/W IC where the data is encoded into the LDPC format and pre-compensates for non-linear transition shift. The amount of write current is set by the 88i9322 (Rev2.0) DSP and Interface/Disk Controller through the serial interface to the preamplifier.

The 88i9322 (Rev2.0) switches the Preamplifier and Write Driver IC to write mode and selects a head. Once the Preamplifier and Write Driver IC receives a write gate signal, it transmits current reversals to the head, which writes magnetic transitions on the disk.

5.5 Firmware Features

This section describes the following firmware features:

Read Caching

Write Caching

Track Skewing

Defect Management

Automatic Defect Allocation

ECC Correction

SMART (Self-monitoring and reporting technology)

ATA security mode features

ATA host protected area

ATA streaming features

ATA power up in stand by feature set

ATA advanced power management (APM) feature set

ATA device configuration overlay (DCO) feature set

5.5.1Read Caching

The Spinpoint M8 hard disk drive uses Read Cache to enhance drive performance and significantly improve system throughput. Use the SET FEATURES command to enable or disable Read Caching. Read caching anticipates host-system requests for data and stores that data for faster future access. When the host requests a certain segment of data, the cache feature utilizes a prefetch strategy to get the data in advance and automatically read and store the following data from the disk into fast RAM. If the host requests this data, the RAM is accessed rather than the disk.

Spinpoint M8 Product Manual REV 2.3

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Contents M8 Product Manual Page Table of Contents Servo System Read and Write Operations Read Fpdma Queued 60h Read Log Extended 2Fh Read Long 22h Table of Tables Scope User DefinitionManual Organization Reference SataIntroduction DescriptionKey Features Hardware Requirements Standards and RegulationsSpindle speed RPM RPM Class SpecificationsSpecification Summary SpecificationsPhysical dimensions Physical SpecificationsLogical Configurations Physical SpecificationsPerformance Specifications Rated Power consumptionPower consumption Power RequirementsEnvironmental Specifications Environmental Specifications15.0 Reliability Specifications Space Requirements InstallationMounting Unpacking InstructionsOrientation Mounting DimensionsMounting-Screw Clearance ClearanceCable Connectors VentilationSata Connectivity Serial ATA Management PowerHDD Power, Sata Interface, and Factory Jumper Connector Pin Locations on the Drive Pcba DC Power Connector and SATA-Bus Interface Cable Connections Drive InstallationDisk Drive Operation Head / Disk Assembly HDABase Casting Assembly DC Spindle Motor AssemblyCoverAssembly Air Filtration System Disk Stack AssemblyHead Stack Assembly Voice Coil Motor and Actuator Latch AssembliesDigital Signal Process and Interface Controller Drive ElectronicsDisk Controller DDR Buffer Control Block Host Interface Control BlockDisk Control Block Disk Ldpc Control BlockFrequency Synthesizer Automatic Gain Control Power ManagementRead/Write IC Time Base GeneratorAnalog to Digital Converter ADC and FIR Analog Anti-Aliasing Low Pass FilterServo System Read and Write OperationsRead Channel Firmware Features Write ChannelRead Caching Write Caching Smart Defect ManagementAutomatic Defect Allocation Multi-burst ECC CorrectionSata Terminology Sata II InterfaceSpinpoint M8 Product Manual REV Signal Descriptions Physical Interface Signal SummaryRegisters When read When written2 I/O Register Address Control Block Register DescriptionsDevice Control Register ex F6h Command Block Register DescriptionsFeatures Register and Feature Extended Register Ex F1h Error Register Ex F1hDevice Register Ex F6h Command Register Ex F7hStatus Register Ex F7h Auto-Activate in DMA Setup FIS Sata II Feature SETDevice Activity Signal Staggered Spin-up Disable ControlPhy. Event Counters Sata Power Management Software Settings PreservationATA Command Descriptions Command TableCommand Code Parameters Check Power Mode E5h Command DescriptionsDownload Micro Code 92h Device Configuration Overlay B1hDevice Configuration Overlay Feature Register Values CommandDevice Configuration Identify data structure Word Content Format Track 50h Execute Device Diagnostics 90hDiagnostic Codes Flush Cache E7h, EAh extendedIdentify Device information Content Description=the fields reported in word 88 are valid EXT =Media Card Pass Through command feature set supported WWN Word Content DescriptionAutomatic Standby Timer Periods Idle E3hIdle Immediate E1h Read DMA C8h, 25h extended Initialize Device Parameters 91hNOP 00h Read Buffer E4hRead Multiple Command C4h, 29h extended Read Log Extended 2FhRead Long 22h Read Native Max Address F8h, 27h extended Read Sectors 20h, 24h extendedRead Verify Sectors 40h, 41h extended Security Erase Unit F4h Security Disable Password F6hRecalibrate 10h Security Erase Prepare F3hSecurity Freeze Lock F5h Security Set Password F1hSecurity Erase Unit Password Word Content Security Set Password data contentSeek 7xh Set Features EFhIdentifier Level Command result Security Unlock F2h12 Transfer Mode Values 11 Set Features Register DefinitionsSleep E6h Set Multiple Mode C6h13 Set Max Feature Register Values Set Max Address F9h, 37h extendedSmart B0h 14 Smart Feature Registers ValuesSmart disable operations D9h Smart enable/disable attribute auto-save D2hSmart execute off-line immediate D4h Smart enable operations D8h15 Device Smart Data Structure Smart read data D0hData Structure Revision Number 16 Smart Attribute Status Flags Bit Name Description18 Off-line Data Collection Status Values 17 Smart Attribute Data List19 Self-test Execution Status Values Self-test execution status byteSmart read log sector D5h Smart return status DAhSmart write log sector D6h Write Fpdma Queued 61h Standby Immediate E0hWrite Buffer E8h Write DMA CAh, 35h extendedWrite Multiple Command C5h, 39h extended Write Long 32hWrite Sectors 30h, 34h extended Spinpoint M8 Product Manual REV Maintenance Maintenance PrecautionsGeneral Information HDD handling guide -Please handle HDD by side surfaces HDD handling guide Prevent Shocks Service and Repair
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