Hard Disk Drives Chapter 7

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

Types of Hard Disks – I

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

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

Types of Hard Disk Interfaces

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

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

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

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

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

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

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

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

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

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

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

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

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

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