IBM C4B 4.51 Brick On Sled carrier 128-pin HPC, SSA manual Power Calculation Examples

Page 16

U S E R RESPONSIBLE F O R V E R I F Y I N G VERSION A N D COMPLETENESS

O E M F U N C T I O N A L S P E C I F I C A T I O N U L T R A S T A R X P ( D F H C ) SSA M O D E L S 1.12/2.25 G B - 1.0" H I G H

2.2.1.1 Power Calculation Examples

Note: The following formulas assume all system ops as a 1 block read or write transfer from a random cylinder while at nominal voltage condition.

Example 1. Calculate the mean 12 volt average current.

If we assume a case of 30 operations/second then to compute the sum of the 12 volt mean currents the following is done.

	mean
+ 1 2 V D C (idle average)	0.28	amps
+ 1 2 V D C (seek average) 0.027 * 30 =	0.081	amps
T O T A L	0.361	amps

Example 2. Calculate the mean plus 3 sigma 12 volt average current.

T o compute the sum of the 12 volt mean current's 1 sigma value assume all the distributions are normal.

Therefore the square root of the sum of the squares calculation applies. Assume a case of 30 operations/second.

	sigma
+ 1 2 V D C (idle average)	0.02	amps
+ 1 2 V D C (seek average) sqrt(30((0.0002)*2))=	0.001	amps

T O T A L	sqrt((0.02)2+(.001)2))=0.02	amps
So the mean plus 3 sigma mean current is 0.361 + 3*0.02 = 0.42 amps
Example 3. Power Calculation.
Nominal idle drive power = (1.23 Amps * 5 Volts) +		(0.28 Amps * 12	Volts) = 9.51 Watts
Nominal R / W	drive power at 30 ops/sec = (1.25 Amps * 5 Volts) +		(0.361 Amps * 12 Volts) = 10.58
Watts

Mean plus 3 sigma drive power for 30 random R / W operations/second. Assume that the 5 volt and 12 volt distributions are independent therefore the square root of the sum of the squares applies.

+ 5 V D C (1 sigma power)		0.05 * 5	=	0.25	watts
+ 1 2 V D C (1 sigma power)		0.02 * 12	=	0.24	watts
Total (1 sigma power) sqrt((0.25)2+(0.24)2)			=	0.347 watts
Total power	9.13 +	3 * 0.347	=	10.2	watts

3The current at start is the total 12 volt current required (ie. the motor start current, module current and voice coil retract current). See Figure 3 on page 20 for typical 12 volt current during spindle motor start.

Page 16 of 87

I B M Corporation

Source filename=POWER

Image 16

Contents Form Factor Disk Drive Version BM Corporation Preface Source filename=STSSHEXT When Reliability Operating LimitsContaminants Acoustic Levels Source filename=STSSHEXT Features General FeaturesInterface Controller Features DescriptionReliability Features ModelsSpecifications GeneralUser bytes/sector ub/sct Sectors/logical block sct/lbaUser bytes/logical block ub/lba Sectors/track sct/trkCapacity Equations For Each NotchFor Entire Drive Power Requirements by Model 1 C1x ModelsInput Voltage + 5 Volts Supply + 1 2 Volts SupplyExample 3. Power Calculation Power Calculation ExamplesExample 1. Calculate the mean 12 volt average current Things to check when measuring 12 V supply current Example 4. Calculate the 12 volt peak currentVolt current during read/write operations C1x Models Typical 12 volt current C1x Models Typical 12 volt spin-up current C1x Models 2 C2x Models Power Calculation Examples Example 4. Calculate the 12 volt peak current Volt current during read/write operations C2x Models Typical 12 volt current C2x Models Typical 12 volt spin-up current C2x Models 3 C4x Models Power Calculation Examples Example 4. Calculate the 12 volt peak current Volt current during read/write operations C4x Models Typical 12 volt current C4x Models Typical 12 volt spin-up current C4x Models CxB Models Power supply methods4.2 DC/DC Converter Grounding Requirements of the Disk Enclosure Hot plug/unplug supportM Corporation Bring-up Sequence and Stop Times Event Nominal MaximumBring-up Sequence Times and Stop Time for C2x Models Source filename=PERFORM Performance Environment DefinitionWorkload Definition # of segments Ub/lba +Command Execution Time SequentialRandom Basic Component DescriptionsData Transfer to/from Disk Comments Data Transfer to/from SSA LinkApproximating Performance for Different Environments Theoretical Data Sector Transfer RateWhen Read Caching is Enabled When Write Caching is EnabledWhen Adaptive Caching is Enabled When Read-ahead is EnabledWhen No Seek is Required For Queued CommandsReordered Commands Back-To-Back CommandsCylinder to Cylinder Skew SkewTrack to Track Skew Idle Time Functions Servo Run Out Measurements Servo Bias MeasurementsPredictive Failure Analysis Channel CalibrationSave Logs and Pointers Command Timeout LimitsDisk Sweep M Corporation Weight and Dimensions MechanicalSmall Form Factor Models CxC ClearancesDimensions are in millimeters Location of Side Mounting Holes of C4C Models Source filename=MECHANIC Unitized Connector Locations Source filename=MECHANIC Carrier Models CxB Dimensions CxB Models M Corporation Handle Docking and Ejection System Auto-docking Assembly Side Rails Side Rail Positioning Electrical Connector and Indicator Locations E D Locations front view CxB Models M CorporationSSA Unitized Connector Electrical InterfaceCarrier Connector PinRow Option Pins and Indicators SSA Link Electrical CharacteristicsSSA Link Cable Device Activity Pin/Indicator Option Port Pin Device Fault Pin/Indicator Option Port PinWrite Protect Option Port Pin Ground long Option Port PinFront Jumper Connector Early Power Off Warning or Power Fail Power Port Pin12 12V Charge and 5V Charge Power Port pin 1 Programmable pin 1 Option Port PinSpindle Synchronization Over Sync Hard-wire M Corporation Source filename=RELIABLE Error Detection Seek Error RatePower On Hours Examples ReliabilityPower on/off cycles Useful LifeMaximum on/off cycles Product LifeInstall Defect Free Mean Time Between Failure *MTBFSpql Shipped product quality level Sample Failure Rate ProjectionsPeriodic Maintenance Connector Insertion CyclesInstall Defect Free percentage Percent ESD ProtectionTemperature Measurement Points Operating LimitsMaximum Reliability P F E TTemperature Measurement Points for all Models bottom view Vibration and ShockOutput Vibration Limits Drive Mounting GuidelinesOperating Vibration Nonoperating Vibration V4SOperating Shock ContaminantsNonoperating Shock Upper Limit Sound Power Requirements Bels for C4x Models Acoustic LevelsSource filename=STANDARD Standards SafetyElectromagnetic Compatibility EMC M Corporation Bibliography Serial Storage Architecture S S a P H Transport