1. Hard Disk Drives
Chapter 7

2. Objectives List the types of hard disks
List the types of hard disk interface
Identify the components of the hard disk
Explain the working of the hard disk
List the different types of filesystem
Install the hard disk
Partition the hard disk
Format the hard disk
Troubleshoot the hard disk

3. Types of Hard Disks – I

4. Types of Hard Disks – II
Standard Drives (IDE/PATA) – ATA transfers data between the hard disk and system using 16 bits with speeds of up to 100 MB/133MB per second
Serial Attachment (SATA) – Transfers data using 1 bit with the speed of 600MB per second
Small Computer Systems Interface (SCSI) Hard Disk Drives – High-speed interface that enables you to connect up to 15 devices on a single port

5. Types of Hard Disks – III
External Hard Disk Drives – Connected using USB2 and Firewire Interfaces
Wireless HDD – Requires external power supply

6. Types of Hard Disk Interfaces

7. Characteristics of Hard Disk Drives
Capacity & Cost – With advance technology cost of the HDD gradually decreased and the capacity of the hard disk also increased
Performance – Depends on the way the data is stored and retrieved on HDD
Reliability – Measured in terms that user should be able to retrieve and store data when required
RPM – RPM is the count of the revolutions made by the hard disk per minute

8. Redundant Array of Inexpensive Disk (RAID)
RAID Levels:
RAID Level 0 – Uses striping (without parity) technique
RAID Level 1 – Uses disk mirroring
RAID Level 4 – Stores the sum of the data on a parity disk
RAID Level 5 – The parity information is not stored on a single hard disk but distributed across all the hard disks in an array
Linear RAID – Combines multiple hard disks together to form one drive
RAID 10 – Merges the RAID level 0 and RAID level 1
RAID 53 – Merges the RAID level 0 and RAID level 3

9. Components of Hard Disk – I
Platters – Round disks that are made up of metal or glass
Recording Media – Made up of a magnetic material such as iron oxide and data is stored in this layer
Read / Write Head – Used to read and write the data on the hard disk
Head Actuator Mechanism – Moves the read/write head from center of the platter to the edge of the platter
Air Filters – Cleans the air circulating in the hard disk
Hard Disk Temperature Acclimation – Time that hard disk must not be used after it is transported from a place having cold climate to a place having warm climate

10. Components of the Hard Disk – II
Spindle Motor – Spins the hard disk platters
Logic Board – Controls the hard disk
Cables and Connectors – Attached to the back of the hard disk
Configuration Items – Sets the hard disk using jumpers
Faceplate – Front plastic covering of the hard disk

11. Working of Hard Disk
User executes a command or the program sends data to be written on the hard disk
Motor in the hard disk drive rotates the disks
Read write head moves over the required track to read the track address from the hard disk for storing the data
Write head converts the binary data into electromagnetic impulses and writes the data on the hard disk
Motor stops rotating the platters in the hard disk

12. Types of File system
File Allocation Table (FAT) – Stores the piece of file data known as clusters on the hard disks
FAT16
FAT32
New Technology File System (NTFS) – Offers high level of security for the stored files
Extended Filesystem (EXT) – Has a root directory and all the files and folders are stored in root directory

13. Partitioning the Hard Disk
Used to create multiple logical drives or partitions
Makes your system start faster and it also enables you to install multiple operating systems on the different partitions
Fdisk utility enables you to divide the hard disk into multiple partitions
Three types:
Primary Partition
Extended Partition
Logical Partition

14. Formatting the Hard Disk
Erases all the contents of the drive
Creates the sectors, tracks and places the file system on the hard disk
Format a hard disk after you install a new hard disk on the system or to erase all the contents on the disk
Two types:
Low Level Formatting
High Level Formatting

15. Troubleshooting Problems that can occur are: System does not Start
Hard Disk Drive contains bad sectors
Hard Disk Drive crashes
Hard Disk does not display the correct formatted size

16. Summary -I A hard disk is a primary and permanent data storage device
A hard disk consists of several circular platters and each platter has read/write heads on both the sides of it
ATA is a standard interface for connecting storage devices such as hard disks and CD-ROM drives
The ATA transfers data between the hard disk and the system using 16 bits with speeds of up to 100/133 MB per second
SATA is a high speed serial interface designed to replace ATA and Ultra ATA drive interface standards

17. Summary -II
The Serial ATA (SATA) transfers data between the hard disk and the system using only 1 bit at a time with the speed of up to 600 MB per second
ATA-4 introduces AT Attachment Packet Interface (ATAPI) which is capable of supporting data transfer rates of up to 33MBps
RAID combines two or more hard disks and treats it as a single drive
The hard disk interface specifies the method used by the hard disk to send and receive data to the system using a data cable

18. Summary -III
SCSI interface enables the hard disk to communicate with the system as very fast speeds
The IDE interface specifies that the hard disk controller is built on the hard disk
The EIDE interface supports a maximum of four hard disk drives on a system
Platters are round disks that are made up of metal or glass
The Read / Write head is used to read the data stored on the hard disk and also write the data to the hard disk

19. Summary -IV
The temperature acclimation specifies the time that the hard disk must not be used after it is transported from a place having a cold climate to a place having a warm climate
The logic board contains the circuit for controlling the different hard disk
The file system determines the way that the files and folders are stored on the hard disk
FAT, NTFS and EXT are the different file systems

20. Summary -V
Partitioning is used to divide the hard disk into sections known as drives
The different types of partitions are primary partition, logical partition and extended partition
Formatting the hard disk creates the sectors, tracks and places the file system on the hard disk and prepares it so that the system can store files on the hard disk
Troubleshooting the hard disk