Hdd.docx

HDD(Hard Disk Drive) Introduction of Hard disk : Virtually every PC sold today has at least one hard disk drive installed inside its system case.  At one time, this was also true of floppy disk drives, but PCs with floppy disk drive are beginning to disappear, giving way to zip disk, super disks, and other forms of removable mass storage.  The hard disk and floppy disk are types of secondary storage, with the PC’s RAM providing its primary storage .  Where primary storage stores data temporarily storage

 While it’s in use, secondary storage holds data, programs and other digital objects permamemtly  In fact, RAM is referred to as temporary storage, and the hard disk and floppy disk are consisdered permenent storage .  The data is not permanent in the sence that it is etched in stone, but compared to the the volatile of RAM, it is far more enduring  Permanent storage on a disk drive means that the data is still available even after the primary power source is removed

 The hard disk is hardly a personal computer invention.  The first hard disk, which first showed up in the 1950s on mainframe computer, were 20 inches in diameter and held only a few megabytes of data.  Hard disk were originally called “FIXED DISK” and “WINCHESTER DRIVE” and became known as hard disk later to differentiate them from floppy drive.  However the basic technology used in the earlist hard disk has not changed all that much over the year although the size and capacity of the drives has.

Hard Disk Drive

IDE Model

SATA Model

External HDD

Pins :- 40Pins (39pins working 1pins not working)

Pins :- 7Pins

USB Model

Power Pin:-15Pins

Pins:- 4Pins

Power Port:-4Pins

Jumper Pin:-No (or) 6Pins

Jumper Pins:-8Pins

HDD Company:1. 2. 3. 4. 5. 6.

Toshiba Seagate Zebronic Samsung Kingstone Western Digital

Cable model & connectivity:1. 2. 3. 4.

IDE (or) ATA – 3Connector SATA Model – 2Connector External HDD – 1Connector SCSI Model – 7-15 Connector (Pins-40Pins)

ABBREVIATION:1. 2. 3. 4. 5. 6.

IDE – Integrated data electronic (or) International data electronic SATA – Serial ATA (or) Serial advance technology USB – Universal serial bus SCSI – Small computer system interface ATA – Advance technology attachment PATA – Parallel advance technology attachment

HDD PARTS:1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

IDE Port IDE Power Port SATA Port SATA Power Port PC Board Back Door Front Door Spindle Motor Media Platter Actuator arm Actuator Read/Write Head (or) silder Actuator Axis Logical Board Ribbon cable Jumper Port

IDE Port:-

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IDE Port

SATA PORT:-

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IDE POWER

JUMPER PORT

Media Platter  Media platter (or) disks as they are more commonly called the primary unit of a hard disk is its disks  The disks are the storage media for the disk drive and it is on them that the data is actually recorded  Disks are made from a number of difference materials each with its own performance & storage characteristics  The primary two materials used in disks are aluminum alloys and glass  The traditional material for platter was an aluminum alloy, which provides strength yet was lightweight.  Many hard disks now use a glass-ceramic composite material for disk platter.  The glass platters are more rigid and as such can be less than half as thick as the aluminum dusk.  A glass disk does not expand or contract with change in temperature which results in a more stable hard disk drive.  Most of the hard disk manufacturers use glass composite materials in their disk drive, including Seagate, Toshiba, and Maxtor  As the disk drive continue to get smaller, storing more data, and operating at higher speed glass materials are likely to be used in all disk drive.

Spindle Motor

 The disk platter are mounted to a spindle separated by disk spacers that keep the platter evenly spaced  The spacers provide a consistent spacing that needed for the read/write heads to have access to the top of one disk and the bottom of the one above it.  In operation the spindle motor rotates the platters in unison at speeds of 3,600rpm(Revolution per minute)4800,5400,7200 and – on newer devices – 10,000 and 15,000rpm.

 A direct drive motor that is mounted directly below it ratates the spindle  The motor that rotates the spindle and the disks mounted to it is called the spindle motor.  The spindle motor is always connected directly to the spindle without using belts or gears so that the drive mechanism is free of noise and vibration which could if transferred to the platter cause data read and write problems.  The spindle is a vital part of the disk drive operation. In fact most hard disk failures are really spindle motor failures  The spindle motor is a brushless and sensorless DC motor that is attached directly to the disk spindle  There are two types of spindle motor in use: in-hub motor that are placed inside the HAD and bottom-mount motors that are attached to the spindle outside of the HAD case

Read/Write Heads Each side of a disk platter has media applied to it that allows it to store data Accordingly each side of a disk platter also has at least one read/write head a disk drive that has two disk platter has four read/write heads There are one exception to this rule but generally a disk drive has two heads for each platter one to read and write data to the top side and one for the bottom side. The read/write heads are all connected to the same actuator mechanism which moves the heads in unison in and out from the spindle to the edge of the platter