Hard disk is a secondary and permanent storage device in the computer. It stores large amount of data. It is a solid state storage device. Reading and writing speed is high. HDD are available from 1 GB to several TB.

1. HARD DISK DRIVES

2. Introduction
 Hard disk is a secondary and permanent
storage device in the computer.
 It stores large amount of data. It is a solid
state storage device.
 Reading and writing speed is high.
HDD are available from 1 GB to severalTB.

3. HDD Architecture
 HDD consists of several
circular platters.
 The platters are divided
into concentric circles
called tracks.
 Tracks are divided into
smaller units called
sectors.

4. Types of HDD
 Standard Drives (IDE).
 SATA Drives.
 SCSI Hard Disk Drives.
 External Hard Disk Drives (USB/Fire wire).
 Wireless Hard Disk Drives.

5. IDE
 Integrated Drive Electronics.
 This technology transfer the data between
the hard disk and system using 16 – bits with
speed of 100 MB/133 MB.
 Two HDD we can connect to a single IDE
connector.
 We have to set the hard disk to master or
slave using jumpers on the HDD.
 It has 40 – pins to connect the system.

6. IDE
 Also known PATA, EIDE.
 IDE cables used to connect these devices to
the motherboard.
 CPU controls the transfer of data from the
hard disk.
 IDE uses either 40 – pins or 80 – pins IDE
cables.
 Length of this IDE cable is maximum 45cm.

8. SATA

10. SCSI HDD
 Small Computer Systems Interface.
 SCSI devices typically used in network server
for lot of processing.
 SCSI is a high speed interface that enables
you to connect up to 15 devices on a single
port.
 SCSI uses RAID technology .

12. RAID
 Redundant Array of Inexpensive Disk.
 It is a technology to access data quickly and
prevents loss of data in case of a hard disk
crash.
 In this technology two or more hard disks acts
like a single hard disk.

13. External HDD
 External hard disk drives can be connected to
either USB or Fire wire ports.
 These devices consumes the power from
ports (Usb/Fire wire).

14. Wireless HDD
 These are small and light in weight.
 These disk drives use 802.11g standard for
communication.
 It is also known asWi – Fi hard disk.
 It requires external power supply.
 Access point uses for data transmission.

16. Characteristics of HDD
 Capacity.
 Cost.
 Performance.
 Reliability.
 RPM.

17. Components of HDD
 Platters.
 Recording media.
 Read/Write head.
 Head Actuator.
 Air Filters.
 Spindle Motor.
 Circuit board.
 Hard DiskTemperature Acclimation.

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