Hard Disk Drives

Hard Disk Drives

Objectives

Ø  List the types of hard disks

Ø  List the types of hard disk interface

Ø  Identify the components of the hard disk

Ø  Explain the working of the hard disk

Ø  List the different types of file system

Ø  Install the hard disk

Ø  Partition the hard disk

Ø  Format the hard disk

Ø  Troubleshoot the hard disk

Types of Hard disk 1

IDE (Integrated Drive Electronics) Drives

Ø  Standard Drives (IDE/PATA/EIDE) – ATA transfers data between the hard disk and system using 16 bits with speeds of up to 100 MB/133MB per second.

Ø  Uses Programmed Input Output (PIO) or Ultra direct Memory Access (UDMA) technology to transfer data.

Ø  Maximum 4 HDDs can be connected

Ø  PATA hard disks are connected to the ATA or IDE port on the motherboard using a 40-pin or an 80-pin cable.

Types of IDE Hard Disk Interfaces - I

Types of IDE Hard Disk Interfaces – II

Ø  ATA – 3 – Supports S.M.A.R.T feature

Ø  ATA – 4 – uses UDMA/33 and DTR is 33MBps. Also called as Advanced Technology Attachment Packet Interface (ATAPI)

Ø  In PIO mode CPU controls the transfer of data from hard disk whereas chipset controls transfer of data in case of UDMA

Types of IDE Hard Disk Interfaces – III

Ø ATA – 5 – uses UDMA/66 with 16 bit data width and 40/80 pin cable

Ø ATA – 6 – Uses UDMA/100 with 16 bit data width and 40/80 pin cable

Ø ATA – 7 – uses DTR up to 133 MBps and requires 80-conductor cable

SATA Drives

Ø Serial ATA transfers data using 1 bit with the speed of up to 600 MB per second.

Ø SATA 150 – First generation SATA interface which is also known as SATA 1 or SATA/150, which has a data transfer rate of 1.5 gigabits per second (Gbit/s).

Ø  SATA 300 – SATA/300 has increased the data transfer rate from 150 MB/s to 300 MB/s and became the fastest desktop hard disk. It is Backward Compatible to SATA 1.5Gbps.

Types of SATA – II

Ø SATA 600 -  Is the third generation serial ATA interface. 

Ø SATA 6.0 increases its data rate to 600 MB/s.

Ø SATA 600 interface is physically identical to SATA 300 and SATA 150 and like these earlier generations of SATA, it can use existing cables and connectors.

Ø The new standard is backward compatible with SATA 300.

eSATA

Ø External SATA (eSATA) is an external interface for SATA technologies.

Ø While eSATA reaches transfer rates triple those of USB 2.0 and FireWire 400, it does have one drawback. eSATA requires its own power connector.

Ø Unlike USB and FireWire interfaces, eSATA does not have to translate data between the interface and the computer. This enhances data transfer speeds

Native Command Queuing (NCQ)

Ø NCQ is a command protocol in serial ATA that allows multiple commands to be outstanding within a drive at the same time.

Ø Drives that support NCQ have an internal queue where outstanding commands can be dynamically rescheduled or re-ordered, along with the necessary tracking mechanisms for outstanding and completed portions of the workload.

Ø Operating systems such as Microsoft Windows and Linux are increasingly taking advantage of multi-threaded software or processor-based Hyper-threading technology.

SCSI and External HDD

Ø Small Computer Systems Interface (SCSI) Hard Disk Drives – High-speed interface that enables you to connect up to 15 devices on a single port

Ø External Hard Disk Drives – Connected using USB2, eSATA and Firewire Interfaces

Solid State Drives (SSD)

Ø SSDs are hard drives without having spinning platters; instead they are based on flash memory

Ø Most SSDs are now 64GB or 128GB in size.

Ø SSDs are faster than hard drives, use less power, and weigh less than traditional spinning hard drives.

Data transfer speed of different hard drives

Name	DTR (Mbit/s)	DTR (MB/s)
SAS	3000	375
eSATA	3000	300
SATA - III	6000	600
SATA - II	3000	300
SATA - I	1500	150
PATA 133	1064	133
FireWire 3200	3144	393
FireWire 800	786	98.25
FireWire 400	393	49.13
USB 3.0	5000	625
USB 2.0	480	60
Ultra-320 SCSI	2560	320

Characteristics of Hard Disk Drives – I

Ø Capacity & Cost – With advances in technology, the cost of the HDD gradually decreased and the capacity of the hard disk also increased

Ø Performance – Depends on the way the data is stored and retrieved on HDD

Ø Reliability – Measured in terms that user should be able to retrieve and store data when required

Ø RPM – RPM is the count of the revolutions made by the hard disk per minute e.g. 5400, 5900 or 7200.

Characteristics of Hard Disk Drives – II

Ø Hard Drive Cache – Disk caching can be used to speed up the hard disk performance. The disk cache uses RAM to provide quick access to frequently accessed data. Mostly 32MB cache is used by desktop hard disk drives.

Ø Hard Drive Interface - The hard drive interface is the computer bus that connects the hard disk drive to the processor and memory. There are two types of hard drive interfaces: the internal interface and the external interface. Mostly SATA interface is used by desktop hard disk drives.

Characteristic of HDDs – III

Components of Hard Disk – I

Ø Platters – Round disks that are made up of metal or glass. Glass platters are preferred as shape of glass does not change when hard disk heats up

Ø Recording Media – Made up of a magnetic material such as iron oxide and data is stored in this layer

Ø Read / Write Head – Used to read and write the data on the hard disk. While the disk is reading or writing data to the disk the head does not touch the disk

Components of Hard Disk – II

Ø Head Actuator Mechanism – Moves the read/write head from center of the platter to the edge of the platter

Ø Air Filters – Cleans the air circulating in the hard disk

Ø 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. Air vents in hard disk are used for equalizing pressure in hard disk

Components of Hard Disk – III

Ø Spindle Motor – Spins the hard disk platters. They have to spin for many continuous hours without causing a lot of vibrations

Ø Logic Board – Controls the hard disk and stores data on hard disk platters

Cables and Connectors

Ø You can attach the power cable and the data cable to the hard disk.

Ø Cable connectors are attached to the logic board of the hard disk and are keyed to ensure that you insert the cables in the correct manner.

Configuration Items – I

Ø Configuration Items – Sets the hard disk using jumpers (show it practically)

•         IDE Jumper Setting - In case of IDE/PATA hard disk drives, you can set the hard disk to master, slave or cable select as per the jumper settings.

Configuration Items – II

Ø SATA Jumper Setting - Function of Jumper block on SATA drives is different in different SATA drives.

Ø For example the jumper block adjacent to the SATA interface connector on SATA 150MB/sec drives is for factory use only, on SATA 300MB/sec drives it can be used to force the drive into SATA 150MB/sec mode.

Working of Hard Disk

Ø User executes a command or the program sends data to be written on the hard disk

Ø Motor in the hard disk drive rotates the disks

Ø Read write head moves over the required track to read the track address from the hard disk for storing the data 

Ø Write head converts the binary data into electromagnetic impulses and writes the data on the hard disk

Ø Motor stops rotating the platters in the hard disk

Partitioning the Hard Disk – I

Ø Two types:

•         Primary Partition –

•         Logical Partition –

•         You can mark one partition as an active and you must have at least one primary partition

•         fdisk utility is not supported by NTFS

Partitioning the Hard Disk – II

Ø Used to create multiple logical drives or partitions

Ø Makes your system start faster and it also enables you to install multiple operating systems on the different partitions

Ø Fdisk utility enables you to divide the hard disk into multiple partitions

Formatting the Hard Disk

Ø Erases all the contents of the drive  

Ø Creates the sectors, tracks and places the file system on the hard disk

Ø Format a hard disk after you install a new hard disk on the system or to erase all the contents on the disk

Ø Two types:

•         Low Level Formatting

•         High Level Formatting

Warning

Ø Do not perform low level formatting frequently as it may damage the HDD.

Troubleshooting

Ø Problems that can occur are:

•         System does not Start

•         Hard Disk Drive contains bad sectors (repair using Flobo software)

•         Hard Disk Drive crashes

•         Hard Disk does not display the correct formatted size

•         A sound is coming from Hard Disk Drive

•         Use of Flobo HDD bad sector repair tool

Summary

Ø A hard disk is a primary and permanent data storage device

Ø A hard disk consists of several circular platters and each platter has read/write heads on both the sides of it

Ø ATA is a standard interface for connecting storage devices such as hard disks and CD-ROM drives

Ø The ATA transfers data between the hard disk and the system using 16 bits with speeds of up to 100/133 MB per second

Ø SATA is a high speed serial interface designed to replace ATA and Ultra ATA drive interface standards

Ø ATA-4 introduces AT Attachment Packet Interface (ATAPI) which is capable of supporting data transfer rates of up to 33MBps

Ø The hard disk interface specifies the method used by the hard disk to send and receive data to the system using a data cable

Ø SCSI interface enables the hard disk to communicate with the system as very fast speeds

Ø The IDE interface specifies that the hard disk controller is built on the hard disk

Ø The EIDE interface supports a maximum of four hard disk drives on a system

Ø Platters are round disks that are made up of metal or glass

Ø The Read / Write head is used to read the data stored on the hard disk and also write the data to the hard disk

Ø The logic board contains the circuit for controlling the different hard disk

Ø The file system determines the way that the files and folders are stored on the hard disk

Ø Partitioning is used to divide the hard disk into sections known as drives

Ø The different types of partitions are primary partition, and logical partition

Ø 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

Ø Troubleshooting the hard disk

Mind Map

Ø Draw a mind map to summarize this chapter