IDE Mass Storage Devices Chapter 7

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IDE Mass Storage DevicesChapter 7

• A Certification Hardware
• Hutchinson Community College
• Computer Support Program

2
Hard Drive Introduction

• Two important mass storage device standards in
  use today are
• Integrated Drive Electronics IDE
• Advanced Technology Attachment ATA
• A newer Standard named Serial ATA is becoming a
  popular standard in computers today.
  SATA

3
Hard Drive Cautions

• Hard drives are not designed as field serviceable
  devices.
• Opening a hard drive will probably make the unit
  unusable.
• Care should also be taken when handling hard
  drives that they not be dropped.
• Most hard drives have a safe drop height of 1
  inch or less.
  

4
Hard Drive Physical Structure

• Hard drive disks, called platters, have a hard
  metal polished surface.
• Each platter normally has two read write heads.
  One for each surface of the platter.
• The platters are covered with a magnetic
  substance that allows storing binary ones and
  zeros to represent data.
• The majority of hard drives in new computers spin
  at a speed of 7200 RPM.
• Other speeds are available 5,400 and 10,000 RPM.
• A few 15,000 RPM IDE drives are available.
• 
  

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Hard Drive Geometry Terminology

• A hard drive has three main characteristics that
  make up the geometry of the device.
• Heads
• Tracks
• Sectors Per Track
  

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Hard Drive Technology
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Read Write Heads

• A read/write arm holds the read/write heads and
  operates with the actuator arm.
• The read/write heads do not contact the platter
  surface, rather they ride on a cushion of air
  just above the platter surface.
• Head Crash occurs if the read/write head
  touches the platter surface.
• A head crash typically makes the platter
  unreadable.
  

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Hard Drive Tracks

• Tracks are concentric circles on the platter.
• Each platter has tracks on the top and bottom
  surface.
• The tracks are divided into storage units called
  sectors.

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Hard Drive Sectors

• Each track on the HD is divided into sectors.
• Each sector can hold 512 bytes of data.
• Under older formatting schemes there were the
  same number of sectors on every track resulting
  in wasted space in the outer sectors.
• A new method of storing data called Zone Bit
  Recording provides a more efficient use of the
  disk space.
  

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Zone Bit Recording

• Does not use the typical pie shaped sector for
  dividing tracks.
• This process allows a different number of sectors
  on each track.
• All sectors are the still the same size, 512
  Bytes.
• Tracks closer to the outside of the disk platter
  have more sectors than inside tracks.
  

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Hard Drive Cylinders

• When storing data on a hard drive, the operating
  system fills an entire cylinder before moving to
  the next one. The access arm remains stationary
  until all the tracks in the cylinder have been
  read or written.
• On hard drives with multiple platters all of the
  tracks that line up vertically are called a
  cylinder.
  

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Cylinders on a Hard Drive
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Calculating Storage Capacity

• A hard drives storage capacity is the product of
  the number of
• Cylinders
• Heads
• Sectors
• And the number of bytes per sector which is
  always 512.

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Begin Day Two
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Hard Drive Partitions

• Before a hard drive can be used it must be
  arranged into partitions and each partition must
  be formatted with a file system.
• Partitions are electronic, logical divisions of
  the physical drive.
• New hard drives can be partitioned using utility
  programs available with the OS.

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Cluster Size

• The operating system sets aside one cluster as
  the minimum for every file.
• A cluster may contain more than one sector.
• A cluster is the smallest addressable area on a
  hard disk
• Cluster size is determined by the size of the
  hard drive and the type of partition on the hard
  drive.
  

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File System

• A file system defines how data is arranged and
  stored on a Hard Drive.
• The file system is determined by the user and the
  operating system.
• Current Microsoft operating systems allow the
  user to choose between more than one file system.
  

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Common File Systems
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Examination Tip

• Windows NT Workstation and NT Server operating
  systems support FAT 16 and NTFS file systems but
  not FAT 32 file system.
• Windows 2000 and Windows XP support all three
  file systems.

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Interface Acronyms

• IDE Integrated Drive Electronics
• EIDE Enhanced IDE
• ATA Advanced Technology Attachment
• ATAPI ATA Packet Interface
• SMART Self-Monitoring, Analysis, and Reporting
  Technology.

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Connecting A Hard Drive To The Computer
Motherboard

• Hard drives as well as CD-ROM drives and DVD
  drives connect to the motherboard through a
  motherboard expansion bus called the IDE/ATA
  expansion bus.
• The current interface is actually an enhanced
  interface called EIDE but the industry still
  refers to this type of mass storage device as an
  IDE device.

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ATAPI

• Advanced Technology Attachment Packet Interface
  (ATAPI)
• Extension to the ATA specification
• Enables non-hard drive devices to connect to the
  PC via ATA controllers
• Same rules on jumper settings
• Hard drives get BIOS thru the System BIOS and
  CMOS
• Non-hard drives get BIOS thru an option ROM or
  software driver

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The IDE Interface

• The IDE interface was designed to handle only
  hard drives.
• It did not include CD-ROM drives or DVD drives.
• This interface only supported one IDE connector
  which limited the computers to a maximum of two
  hard drives with out special expansion cards.

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The IDE/ATA Interface Socket

• Modern motherboards will have two interface
  sockets.
• Each socket is capable of interfacing two IDE
  devices.
• In some cases there will be a primary and a
  secondary interface socket
• The primary interface is usually a bright blue or
  red and is the faster of the two sockets
• The secondary socket maybe white, brown or black
  provides slower data transfer rates than the
  primary socket.

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IDE / EIDE continued

• Hard drive controller is integrated with the
  drive
• ATA drives are typically called IDE drives
• EIDE added some enhancements to IDE
• Higher capacities
• Support for non-hard drive devices like CD-ROMs
• Support for up to 4 hard drives
• ATA, IDE, and EIDE are used interchangeably today
  to describe all ATA devices.

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Serial ATA

• Serial ATA is able to transfer data at 1.5 Gbps,
  nearly 3 times the speed of the current Ultra
  ATA/66 interface.
• Serial ATA is expected to reach transfer speeds
  of 6 Gbps.
• The parallel ribbon cables are replaced with a
  thin serial cable.
• The SATA is hot swappable
• Cable length are increased to a maximum of 39.4
  inches rather than 18 inches.
• Host adapter cards and power connector series
  adaptors allow adding a serial ATA drive to
  existing motherboards.

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Serial ATA

• More on SATA
• Hot-swappable
• Throughput of 150 MBps (with potential of 600
  MBps)
• A parallel ATA device (PATA) my be connected to
  SATA using a SATA bridge
• Add SATA functionality via a PCI card
• Only one device per controller

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Hard Drive Installation

• Installing a new hard drive is a simple task the
  steps are
• Set IDE jumpers correctly
• Physically install the drive
• Attach the power and data cable to the drive
• Attach the data cable to the motherboard
• At this point you are ready to electronically
  configure the drive for use.

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IDE Jumper Settings
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Single, Master, Slave

• Typically an IDE drive must be set to one of
  these three configurations using the jumpers on
  the back of the drive.
• Single is used when only one drive is installed
  in the PC.
• When two drives are on one cable one must be the
  master and the other the slave.
• The fastest device should be the master.
  

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Cable Select

• Another IDE configuration option is Cable Select.
• A device is automatically assigned as master or
  slave depending on which cable connector the
  device is attached.
• This option requires
• A special cable with pin 28 blocked or cable 28
  open
• BIOS support
• Device support
  

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• To install the drive as a single drive, or to
  install the drive as a master drive in a dual
  drive system, jumper the adapter on pins 5
  6.   
• To install the drive as a slave drive in a dual
  drive system, jumper pins 3 4.
• Pins 1 2 are for cable select. When these two
  pins are jumpered, the position of the adapter on
  the cable determines whether the drive is a
  master or slave. If the drive is attached to the
  middle of the cable, the drive will be the
  master. If the drive is attached at the end of
  the cable, the drive will be a slave. Note the
  cable select jumpers should only be used if your
  system and cable support this feature.

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Power and Data Cables

• IDE devices use the large Molex plug for the
  power connection.
• The power plug is keyed.
• On the flat parallel data cable one of the wires
  will be colored red or blue. This wire goes
  closest to the power connector.

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IDE Cables and Connectors

• ALL IDE devices use a 40 pin connector.
• Newer, faster transfer data rate devices, use an
  80 conductor cable but still use the 40 pin
  connector.
• The 80 conductor cables are typically round while
  the older 40 conductor cables are flat.

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The 80 Conductor Cable

• To achieve speeds above 33 Mbps a cable with 80
  rather than the usual 40 conductors was designed.
• The additional 40 wires provide a ground return
  and shield for each of the other 40 conductors.
• The shielding reduced the crosstalk between data
  cables that occurred at higher data transfer
  speeds.

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Comparison of 40 and 80 Conductor Cables
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EIDE relationship to ATA

• Most computers sold today use an enhanced version
  of IDE called Enhanced Integrated Drive
  Electronics (EIDE). In today's computers, the IDE
  controller is typically built into the
  motherboard.
• IDE was adopted as a standard by American
  National Standards Institute (ANSI) in November,
  1990.
• The ANSI name for IDE is Advanced Technology
  Attachment (ATA).

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New Hard Drive Designations

• Hard drives classified with the ATA standard are
  typically identified like ATA/66.
• ATA/66 indicates that the maximum data transfer
  rate is 66Mbps.
• Other typical drives are ATA/100 and ATA/133
  drives.

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History of the ATA Interface
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BIOS Information

• To be recognized by the system a hard drives
  geometry must be entered into the system BIOS.
• Two methods for entering the data are
• Auto
• User

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Auto Setup

• Auto detection function runs every time the PC
  boots.
• This allows new devices to recognized at each
  boot.
• It does take extra time to start the machine if
  you select auto.
  

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User Setup

• You can set CMOS to user and BIOS will determine
  the drives geometry once and save the information
  in CMOS.
• Once the hard drive type us is determined the CHS
  and size settings are automatically configured.
• The drive is not checked each time the machine
  starts.

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IDE Drive Configuration

• When installing a new hard drive be sure that
  the BIOS Auto-Detect feature is enabled
• Auto-Detect determines the drive type for the
  system with out intervention from the technician.
• Current technology BIOS uses a method called
  Logical Block Addressing (LBA) to communicate
  with the hard drive.
  

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ATAPI

• A standard designed to provide commands necessary
  for devices such as
• CD-ROM Drives
• Zip Dries
• Backup Tape Drives
• Other removable Media
• This interface has the advantage of working with
  the IDE adapter socket on the motherboard.

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Partitioning a Hard Drive.

• The first step to prepare a new hard drive to
  receive data is to partition the drive.
• Partitioning can be done with a DOS utility
  program named FDISK or can be accomplished from
  Windows from Computer Management.
• Even if the drive will not be subdivided you must
  partition the drive and set the primary partition
  as the active partition.

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Partitioning Advantages

• Divides the drive into separate sub-units each
  with an individual drive letter.
• Drive letters are assigned by the operating
  system.
• Partitioning allows the hard drive to separate
• Multiple operating systems
• Application programs
• Data
• Provide data security
• Uses the hard drive to its full capacity

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Partitioning A Hard Drive Using The FDISK Utility

• It is much easier to see all the steps involved
  in partitioning a hard drive while using FDISK.
• We will use that method to learn about Disk
  Partitions.

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Partitioning Terms

• Primary Partition
• Extended Partitions
• Logical Drives
• Active Partition
• FDISK
• FORMAT

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Primary Partition

• The first partition on the first physical drive
  in the system is the primary partition.
• The primary partition my be the entire hard drive
  or a smaller part of the total disk.
• For example an 30GB drive might have a primary
  partition of only 5GB.
• The primary partition on the first physical disk
  drive detected by the operating system is
  assigned the drive letter C.

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Extended Partition

• The extended partition on a hard drive is all of
  the space on the hard drive not used as the
  primary partition.
• If the primary partition uses all the disk space
  then there is no extended partition.

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Logical Drives

• Logical drives are divisions of the extended
  partition.
• An extended partition can be divided into as many
  as 23 logical drives.
• Drive letters A B are reserved for floppy
  drives, drive letter C is reserved for the
  Primary partition so Logical drives can begin
  with the letter D and continue to the letter Z.

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Active Partition

• This partition can be made to be bootable, that
  is to contain the necessary system files to allow
  starting the computer.
• The primary partition should be the active
  partition and is where the operating system
  should be loaded.

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FDISK

• FDISK is a Microsoft utility program used to
  partition a hard drive.
• FDISK is available through DOS and Windows95/98.
• After a disk is partitioned it must be formatted
  before it can be used to store data.
• All drives, physical and logical, must be
  individually formatted.

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Steps to Partitioning a hard drive

• Start the utility program FDISK
• Create the PRIMARY partition
• Set the primary partition active
• Create the EXTENDED partition
• Create any LOGICAL drives needed
• FORMAT each partition

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High Level Format

• The last step in partitioning a drive is to
  format the drive using the FORMAT command.
• This command completes a high level format of
  the hard drive which sets up the FILE SYSTEM so
  that the hard drive can accept data.

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Making A partition Bootable

• When the active partition is formatted using the
  /S (system switch) will make the partition
  bootable
• A bootable partition or diskette will contain
  three files
• IO.SYS
• MSDOS.SYS
• COMMAND.COM
• The SYS command can also be used to transfer
  these files to a formatted drive.
  

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Computer Management Window
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High Level Format

• The last step in partitioning a drive is to
  format the drive.
• One way to FORMAT a drive using the DOS FORMAT
  command. This will produce either a FAT 16 or
  FAT 32 File System
• The Hard Drives can also be formatted using
  Windows NT/XP/ 2000 and install a FAT 32 or NTFS
  file system.
• Formatting a hard drive sets up the FILE SYSTEM
  so that the hard drive can accept data.
• Using My Computer all versions of windows allow
  you to right click a drive or partition to
  format.

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Using Disk Management

• Windows 2000/XP allow a disk to be formatted from
  Disk Management.
• Right click (alternate) an unformatted partition
  of a hard drive to start the formatting dialog.
• See figure 7.14 page 163.

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Making A partition Bootable

• When the active partition is formatted using the
  /S (system switch) will make the partition
  bootable
• A bootable partition or diskette will contain
  three files
• IO.SYS
• MSDOS.SYS
• COMMAND.COM
• The SYS command can also be used to transfer
  these files to a formatted drive.
  

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The Acronym RAID

• Redundant Array of Inexpensive Disks
• Redundant Array of Independent Disks (less
  common)

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RAID Level 0 Disk Striping

• Disk Striping
• Writes data across multiple drives at once
• Requires at least 2 hard drives
• Does not provide redundancy
• If any drive fails, the data is lost

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RAID Level 1 Disk Mirroring

• Disk Mirroring is the process of writing the same
  data to two drives at the same time
• Requires at least two drives
• Produces an exact mirror of the primary drive
• Mirroring uses the same controller
• Mirror-Duplexing uses separate controllers

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RAID Level 2

• Disk Striping with Multiple Parity Drives
• Not used

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RAID Levels 3 and 4

• Disk Striping with Dedicated Parity
• Dedicated data drives and dedicated parity drives
• Quickly replaced by RAID 5

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RAID Level 5

• Disk Striping with Distributed Parity
• Distributes data and parity evenly across the
  drives
• Requires at least 3 drives
• Most common RAID implementation

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RAID Level 6

• Super Disk Striping with Distributed Parity
• RAID 5 with asynchronous and cached data
  capability

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Implementing RAID

• RAID provides a general framework but does not
  say how to implement RAID
• Multiple hard drives hooked together is the first
  stepwhether SCSI or ATA
• Next, should you use hardware or software to
  control the array?
• Software is cheaper and does not require special
  controllers but taxes the OS and is slower
• Windows NT and Windows 2000 Server provide
  software RAID solutions
• Hardware provides speed with data redundancy at a
  price
• Most common implementations
• Includes hot swapping

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Personal RAID

• ATA RAID controller chips have gone down in price
• Some motherboards are now coming with RAID
  built-in
• RAID has been around for 20 years but is now less
  expensive and moving into the desktop system