Seagate ST33000651AS Set Features command, Aah, Enable read look-ahead read cache feature default

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SATA Interface

10Ultra DMA mode 2 is currently active.

11Ultra DMA mode 3 is currently active.

12Ultra DMA mode 4 is currently active.

13Ultra DMA mode 5 is currently active.

14Ultra DMA mode 6 is currently active.

4.3.2Set Features command

This command controls the implementation of various features that the drive supports. When the drive receives this command, it sets BSY, checks the contents of the Features register, clears BSY and generates an interrupt. If the value in the register does not represent a feature that the drive supports, the command is aborted. Power-on default has the read look-ahead and write caching features enabled. The acceptable values for the Features register are defined as follows:

Table 8 Set Features command values

02H

Enable write cache (default).

03H

Set transfer mode (based on value in Sector Count register).

 

Sector Count register values:

 

 

 

00H Set PIO mode to default (PIO mode 2).

 

01H Set PIO mode to default and disable IORDY (PIO mode 2).

 

08H PIO mode 0

 

09H PIO mode 1

 

0AH PIO mode 2

 

0BH PIO mode 3

 

0CH PIO mode 4 (default)

 

20H Multiword DMA mode 0

 

21H Multiword DMA mode 1

 

22H Multiword DMA mode 2

 

40H Ultra DMA mode 0

 

41H Ultra DMA mode 1

 

42H Ultra DMA mode 2

 

43H Ultra DMA mode 3

 

44H Ultra DMA mode 4

 

45H Ultra DMA mode 5

 

46H Ultra DMA mode 6

10H

Enable use of SATA features

55H

Disable read look-ahead (read cache) feature.

82H

Disable write cache

90H

Disable use of SATA features

AAH

Enable read look-ahead (read cache) feature (default).

Barracuda XT SATA Product Manual, Rev. D

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Contents
100586689 Rev. D September BarracudaXTRevision Date Description of changes Revision HistoryContents Barracuda XT Sata Product Manual, Rev. D Figures Barracuda XT Sata Product Manual, Rev. D Seagate Technology Support Services Barracuda XT Sata Product Manual, Rev. D About the Serial ATA interface IntroductionDrive Specifications Formatted capacity LBA modeDefault logical geometry Start/stop times Physical characteristicsPower specifications Recording and interface technologyStandby mode Read/write power and currentOperating power and current Idle mode powerTypical 12V startup and operation current profiles 3000GB Typical 5V startup and operation current profiles 3000GBTypical 12V startup and current profiles 2000GB Typical 5V startup and current profiles 2000GBVoltage tolerance Power management modesConducted noise Altitude Environmental specifications Ambient temperatureTemperature gradient HumidityAcoustics ShockVibration Test Description Performance level Reference Standard Test for Prominent Discrete Tones PDTsElectromagnetic immunity FCC verification WarrantyAgency certification Safety certification Electromagnetic Compatibility EMCCorrosive environment Environmental protectionChina Restriction of Hazardous Substances RoHS Directive Drive Specifications Serial ATA cables and connectors Handling and static-discharge precautionsConfiguring the drive Attaching Sata cabling Drive mountingMounting dimensions 3000GB model Mounting dimensions 2000GB model Ground 2nd mate 3V powerSegment Pin Function Definition P14 3V power, pre-charge, 2nd mate12V power, pre-charge, 2nd mate 12V powerCommand name Command code in hex Supported ATA commandsCommand name Word Description Value Identify Device command57-58 Current capacity in sectors Or Write Multiple commandNumber of current logical heads Number of current logical sectors per logical trackFffeh BE01H00DEH Bit Word AAH Set Features commandEnable read look-ahead read cache feature default Code in features register A.R.T. command 3 S.M.A.R.T. commandsBarracuda XT Sata Product Manual, Rev. D Master/slave 9 mountingBarracuda XT Sata Product Manual, Rev. D Barracuda XT Sata Product Manual, Rev. D Barracuda XT Sata Product Manual, Rev. D Page ASIA/PACIFIC Seagate Technology LLC
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