Understanding and Installing Hard Drives

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Chapter 8

• Understanding and Installing Hard Drives

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You Will Learn

• About hard drive technologies
• How a computer communicates with hard drive
  firmware
• How a hard drive is logically organized to hold
  data
• How to install a hard drive
• How to solve hard drive installation problems

3
Hard Drive Technologies

• Used by hard drive to interface with the system
• Used within hard drive to read and write data to
  the drive

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Hard Drive Subsystem
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Types of Hard Drive Interfaces

• EIDE (Enhanced IDE) interface standards used by
  most hard drives
• Other interface standards
• IDE (Integrated Drive Electronics)

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EIDE Interface Standards

• Specify data transfer speed more than any other
  factor
• Considerations when selecting a standard
• Use fastest standard appropriate for range of the
  system and size of the drive
• Must be supported by the OS, system BIOS on
  motherboard, and firmware on the drive
• Ultra ATA/100 most popular

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EIDE Interface Standards (continued)

• Modes of transferring data between hard drive and
  memory
• PIO transfer mode (Programmed Input/Output )
• The original method used to transfer data between
  the CPU (through the ATA controller) and an ATA
  device.
• DMA transfer mode (Direct Memory Access)
• Allows certain hardware subsystems within a
  computer to access system memory for reading
  and/or writing independently of the CPU.

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EIDE Interface Standards (continued)

• IDE cabling methods
• Parallel ATA (PATA) technology
• Serial ATA (SATA) technology
• Independent device timing

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ANSI Interface Standards
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ANSI
Acronym for the American National Standards
Institute. Founded in 1918, ANSI is a voluntary
organization composed of over 1,300 members
(including all the large computer companies) that
creates standards for the computer industry.
In addition to programming languages, ANSI sets
standards for a wide range of technical areas,
from electrical specifications to communications
protocols. For example, FDDI, the main set of
protocols for sending data over fiber optic
cables, is an ANSI standard.
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IDE Cabling Methods
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IDE Cabling Methods (continued)
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IDE Cabling Methods (continued)
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Configuring EIDE Drives

• EIDE standards support two IDE connections, a
  primary and a secondary
• Each connection can support up to two IDE devices
  for a total of four devices on a system
• Primary IDE channel, master device
• Primary IDE channel, slave device
• Secondary IDE channel, master device
• Secondary IDE channel, slave device

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Configuring EIDE Drives (continued)
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Other Interface Standards

• SCSI (small computer system interface)
• USB
• IEEE 1394
• Fibre Channel

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How Hard Drives Work
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How Hard Drives Work (continued)
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Tracks and Sectors on the Drive
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Tracks and Sectors on the Drive (continued)
CAV
Short for constant angular velocity, a technique
for accessing data off of rotating disks. With
CAV, the disk rotates at a constant speed
regardless of what area of the disk is being
accessed. This differs from Constant Linear
Velocity (CLV), which rotates the disk faster for
inner tracks. Disk drives use CAV, whereas
CD-ROMs generally use CLV, though some newer
drives use a combination of CAV and CLV. The
advantage of CAV is that it is much simpler to
design and produce because the motor doesn't need
to change speed. In addition, CLV runs into
problems for very high-speed CD-ROMs because
there's a brief latency whenever the drive needs
to change the rotational speed.
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Tracks and Sectors on the Drive (continued)
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Tracks and Sectors on the Drive (continued)
Zone Bit Recording
A method of recording data on a hard disk drive
whereby the sectors per track on the drive are
not consistent across the platter. In general,
tracks closest to the center have fewer sectors
than tracks toward the outside of the platter
where the tracks are larger and can fit more
sectors.
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Low-Level Formatting

• Occurs at the factory
• Process of writing sector and track markings on
  the disk i.e. creates sectors tracks
• Expected to last for the life of the drive

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Considerations When Purchasing a Hard Drive

• Capacity
• Spindle speed
• Technology standard
• Cache or buffer size
• Average seek time
• Match drive to motherboard

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Communicating with the Hard Drive Controller
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Calculating Drive Capacity on Older Drives

• For drives less than 8.4 GB
• Determined by number of heads, tracks, and
  sectors on the disk, each sector holding 512
  bytes of data

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Hard Drive Size Limitations
Operating system Maximum size supported
DOS and Windows 9x FAT16 2.1 GB cannot be used on hard drives that exceed 8.4 GB
Windows NT/2000/XP FAT16 4 GB
Windows 2000/XP FAT32 32 GB
Windows 9x FAT32 137 GB
Windows 2000/XP with Service Pack Larger than 137 GB
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Methods of Retaining Backward Compatibility

• CHS (Cylinder, Head, Sector) mode or normal mode
  (for drives less than 528 MB)
• Large mode or ECHS (Extended CHS) mode (for
  drives between 504 MB and 8.4 GB)
• LBA (Logical Block Addressing) mode (for drives
  larger than 504 MB)
• 33.8 GB limitation and 137 GB limitation
• Device drivers

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Methods of Retaining Backward Compatibility

• CHS (Cylinder, Head, Sector)
• Large mode or ECHS (Extended CHS) mode
• LBA (Logical Block Addressing) mode

The drive was accessed by specifying its
cylinder, head and sector address. More
appropriately, it was referred to as accessing
the drive through its "geometry".
A transition change in the way a drive was
accessed in order to work around the 504 MB
barrier, however, the addressing was still done
in terms of cylinder, head and sector numbers and
then translated one or more times before actually
accessing the drive itself.
It is a means by which a drive is accessed by
linearly addressing sector addresses, beginning
at sector 1 of head 0, cylinder 0 as LBA 0, and
proceeding on in sequence to the last physical
sector on the drive, which, for instance, on a
standard 540 Meg drive would be LBA 1,065,456.
I.e, each sector is assigned a unique "sector
number".
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How a Hard Drive Is Logically Organized to Hold
Data

• Steps for preparing a hard drive to hold files
• Low-level format (usually done at the factory)
• Partitioning the hard drive
• High-level format

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Hard Drive Partitions and Logical Drives

• Active partition Its the bootable partition.
  OS installed in this partition. Only one drive
  can be set as the active partition on a computer.
• Primary partition The primary partition marked
  as active contains the OS. Also referred as
  System Partition.
• Extended partition Can be broken down into
  smaller drives accessible to the OS. These drives
  are referred to as logical partitions or logical
  drives.
• Logical partition Exists in an extended
  partition.

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Partitions and Logical Drives
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Hard Drive Partition Table in MBR
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Choice of File Systems

• FAT16
• Supported by all Windows systems
• FAT32 (and VFAT)
• Supported by Windows 95 Second Edition, Windows
  98, Windows 2000, Windows XP
• NTFS
• Supported by Windows NT, Windows 2000, Windows XP
• Each logical drive has its own file system

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Size of Logical Drives
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When to Partition a Drive

• First install a new hard drive
• Existing drive is giving errors
• Suspect a virus has attacked the drive
• Want to wipe a hard drive clean and install a new
  OS

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Installing a Hard Drive

1. Set jumpers or DIP switches physically install
   drive attach power cord and data cable
2. Inform CMOS of new drive
3. If installing an OS on the drive, boot from OS
   setup CD (and skip next two steps)
4. If drive is not intended to hold an OS, use Fdisk
   or Disk Management to create partition(s) and
   divide extended partition into logical drives
5. For second drive, use Format command or Disk
   Management to high-level format each logical drive

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Prepare for Installation

• Read documentation
• Plan drive configuration
• Prepare work area and take precautions

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Jumper Settings
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Jumper Settings (continued)
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Jumper Settings (continued)
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Mounting the Drive in the Bay
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Mounting the Drive in the Bay (continued)
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Mounting the Drive in the Bay (continued)
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Mounting the Drive in the Bay (continued)
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Mounting the Drive in the Bay (continued)
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Mounting the Drive in the Bay (continued)
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Mounting the Drive in the Bay (continued)
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Mounting the Drive in the Bay (continued)
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If the Bay Is Too Large
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Use CMOS to Change Hard Drive Settings
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Setup for Large-Capacity Hard Drives
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Setup for Large-Capacity Hard Drives (continued)
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Setup for Large-Capacity Hard Drives (continued)
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Using Fdisk to Partition a Drive
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Using Fdisk to Partition a Drive (continued)
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Using Fdisk to Partition a Drive (continued)
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Format Each Logical Drive

• After using Fdisk, you must reboot the PC before
  you format the drive
• Commands used to format logical drives C, D, and
  E
• Format C/S
• Format D
• Format E

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Using Windows to Partition and Format a New Drive

• Boot from Window setup CD
• Follow on-screen directions to install Windows on
  new drive
• The setup process partitions and formats new
  drive before it begins Windows installation

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Troubleshooting Hard Drive Installations

• Check CMOS setup to verify that system BIOS
  recognizes large drives
• Verify status of Fdisk
• Verify that Format C/S was done
• Check configuration of CMOS setup
• Confirm setting of DIP switches or jumpers
• Check connection of power cord and data cable
• Refer to Web site of manufacturer for suggestions

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Summary

• Introduction to hard drive technology
• How a hard drive is logically organized
• Physical characteristics of a hard drive
• How the OS and system BIOS communicate with the
  hard drive
• How to install a hard drive
• Troubleshooting hard drive installation problems