Hard Disk

· What is Hard Disk?

– Stores data in magnetic disk like medium

· Non-volatile mass storage device.

· Has very high access time as compared to RAM (10-20 million ns).

· Very cheap as compared to RAM and so large in capacity.

· Interface standards

– IDE (Integrated Drive Electronics)

∗ The hard disk drive includes the drive controller circuitry and hence known as IDE.

∗ It can support atmost 4 devices.

∗ 16 bit interface standard; 40 pin/80 pin connector.

∗ ATA-33/66

· Interface standards contd...

– SCSI (Small Computer System Interface)

∗ General pupose interface standard used for connecting many types of devices to the PC.

∗ Supports 7 to 15 different devices like hard disk, scanner, CD ROM etc.

∗ 32 bit interface standard and more expensive than IDE.

∗ Allows simultanous access for faster data transfer.

· Connecting Multiple IDE Harddisks/CD-Roms

– Primary/Secondary and Master/Slave settings – Jumper settings

· Performance parameters

– Rotation speed.

– Average seek time.