What is hard disk? ·Track:storing data. Goal:correctly position the reader head to track, to read the data. What is ms? Control variables:position. Do we care? Position accuracy:lum. Track seek time:50ms Cover Spindle Disk Rotation of arm Desired position Input voltage Actual position Arm Control Motor and DC motor device read arm Track a Track b Sensor Vaccumm Head sliderWhat is hard disk? • Track: storing data. • Goal: correctly position the reader head to track, to read the data. • Control variables: position. • Position accuracy: 1m. • Track seek time: 50ms Control device Motor and read arm Sensor Desired position Actual position Input voltage What is ms? Do we care?