Implementing Hard Drives

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Implementing Hard Drives
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Overview

• In this chapter, you will learn to
• Explain the partitions available in Windows
• Discuss the formatting options
• Partition and format a hard drive
• Maintain and troubleshoot a hard drive

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Hard Drive Partitions
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Partitioning

• Process of electronically subdividing the
  physical hard drives
• Windows assigns them names like C or D
• A hard drive must have at least one partition
• Partitioning enables organization of a drive that
  suits your personal taste

• One physical drive
• One or more logical partitions

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Essentials
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Basic Disks

• Master Boot Record
• Small amount of code that takes control of boot
  process
• Looks in partition table for partition holding
  valid operating system
• MBR and partition table stored in boot sector
• Only one MBR per disk

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Basic Disks

• Support up to four partitions
• Can have four primary partitions or 3 primary
  partitions and one extended partition
• Primary partition bootable
• Extended partitions non-bootable
• Can hold multiple logical drives lettered D-Z

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Partitioning

• Primary partitions
• Store bootable operating system
• Disk can have up to four primary partitions
• Active partition is one currently booted to
• Only one primary partition can be active at a time

• Extended partitions
• Extended partitions are not bootable
• Disk can have only one extended partition
• They can be divided into many logical drives
• Strength is number of drive letters that can be
  used D- Z

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Primary Partitions

• Can be used for dual-boot or multi-boot
  configurations
• More than one bootable partition
• Third party tools available to identify primary
  partitions and provide choices
• Partition booted to currently is marked as active
  partition

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Dynamic Disks

• New since Windows 2000 (Server and Workstation)
• Not available in XP Home Edition
• Partitions called Simple Volumes
• No limitation on number of volumes
• Added capabilities
• RAID 0, 1, 5 on Windows Server products
• RAID 0 on Windows desktop products
• Extended and spanned volumes
• RAID covered in last chapter
• Other volumes covered in more depth later in
  chapter

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Other Partitions

• Hidden partition
• Primary partition hidden from operating system
• Used to hide a backup copy of OS
• Swap partition
• Only on Linux and BSD systems
• Entire partition that works like paging file in
  Windows

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When to Partition

• Older OSs required partitioning before
  installation
• Command line program called FDISK
• Windows 2000 and above include partition tool in
  install program

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When to Partition

• After installation
• Windows 2000 and above use GUI called Disk
  Management
• Third party tools available such as
• GParted (Linux tool that works on Windows
  partitions)
• Partition Magic

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Hard Drive Formatting

• Formatting configures a partition to hold files
  and folders suitable to the operating system
• Two major functions of formatting
• Creates a file system
• Creates root directory

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File Systems

• Windows supports three different file systems
• FAT16 (often called just FAT)
• FAT32
• NTFS

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File Allocation Table (FAT)

• File Allocation Table (FAT) keeps track of the
  sectors that store the various parts of a file
• 16-bit FAT (FAT16) uses 4 hexadecimal digits to
  number the sectors
• 0000 thru FFFF
• FAT is like a 2-column spreadsheet
• Column one numbers the sectors
• Column two contains the status of the sector
• Bad sectors FFF7
• Good sectors 0000
• Format creates the FAT and then writes and reads
  from each sector to see if it is good

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FAT Limitations

• 16 bits can address only 64K (216) sectors
• Sector sizes limited to 512 bytes
• 64K X 512 bytes 32 MB max size
• Solution was clustering allowing partitions sizes
  up to 2 GB

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Clustering

• Clustering combines a set of contiguous sectors
  and treats them as a single unit
• Called a cluster or file allocation unit
• Instead of numbering the sectors, clusters were
  numbered
• Allowed partition sizes up to 2 GB
• DOS, Windows 3.1, and the first version of
  Windows 95 all uses FAT16
• Newer operating systems also support FAT16

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How FAT Works

• Windows looks for the first cluster marked 0000
  (good available for use)
• If the file fits in that cluster FFFF is put in
  the status column
• If the file is larger than the cluster, Windows
  finds the next open cluster
• That open clusters number is put in the first
  status field in order to know where to link
• Process continues until the file is fully stored
• Last clusters status field is marked FFFF
  (end-of-file)

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Example of FAT Storage
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3
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0000 Good FFF7 Bad FFFF End of File
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Fragmentation

• Fragmentation occurs when files are spread across
  drives (not contiguous)
• Individual files are broken into pieces that fit
  into a sector or cluster
• The various pieces are stored on the hard drive
  but may not be stored in contiguous clusters
• Fragmentation slows down the system during hard
  drive reads and writes
• Programs like Disk Defragmenter or Speed Disk
  could be used for defragmenting files, folders,
  or both

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Fragmented file

• Takes longer for system to piece together and can
  impact performance

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Disk Defragmenter

• Can defragment disk

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FAT32

• FAT32 was introduced with Windows 95 OSR2 (OEM
  Service Release 2)
• Supports partitions up to 2 terabytes
• Uses 32 bits to describe each cluster
• Allows the use of small clusters
• Can still become fragmented

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IT Technician NTFS
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NTFS

• File System of choice today
• Six major improvementsand refinements
• Redundancy
• Security
• Compression
• Encryption
• Disk quotas
• Cluster sizing

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NTFS Improvements

• NTFS Structure
• Uses an enhanced file allocation table called the
  Master File Table (MFT)
• NTFS keeps a backup copy in the middle of disk
• Security
• Provides file and folder access control
• Uses Access Control List with permissions
• If youre on the list youre granted the specific
  permission

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NTFS Improvements

• Compression
• Allows files and folders to be compressed to save
  space
• Encrypting File System
• Allows files and folders to be encrypted and
  unreadable to anyone without the key
• Files and folders can beencrypted OR compressed

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NTFS Improvements

• Disk Quotas
• Can control how spaceusers can use
• Set on a per drive basis
• Cluster Sizes
• Can adjust cluster sizes
• Rare to do so
• NTFS supports 2 TBpartitions

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Partitioning and Formatting Process
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Bootable Disks

• Any removable media that has a bootable OS
  installed
• Floppy, CD-ROM, USB thumb drive
• All Windows and Linux installation CDs are
  bootable
• Common to create bootable media with tools added

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Partitioning and Formatting

• With Windows Installation CD
• During text portion of install
• Can create single partition

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Partitioning and Formatting

• With Windows Installation CD
• Allows you to set the size of the drive
• Minimum of 8MB up to size of drive

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Partitioning and Formatting

• With Windows Installation CD
• Can format the drive with a file system
• NTFS Quick not as thorough
• NTFS Regular checks the drive

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Partitioning and Formatting

• With Windows Installation CD
• Can create multiple partitions

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PATA Drive Letter Assignments

• Primary partition of the
• Primary master drive
• Primary slave drive
• Secondary master drive
• Secondary slave drive
• Then all logical drives in the extended partition
  of the
• Primary master drive
• Primary slave drive
• Secondary master drive
• Secondary slave drive

CDEF
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SATA Drive Letter Assignments

• Similar to PATA, but based on order set in CMOS
• Primary partition of the first drive
• Primary partition of the second drive
• Primary partition of the third drive
• Etc.
• All logical drives in extended partition of first
  drive
• All logical drives in extended partition of
  second drive
• All logical drives in extended partition of third
  drive
• Etc.

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Disk Management

• GUI in Windows 2000 and XP
• Used to manage partitions
• Part of Computer Management
• Can be launched directly with diskmgmt.msc

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Creating a New Partition

• Alt-click in Unallocated space and choose New
  Partition

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New Partition Wizard
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Disk Management

• Creating a partition in Windows
• Pick partition type, size, and assign drive
  letter
• lt 4 GB can choose FAT, FAT32, or NTFS
• 4 GB to 32 GB can choose FAT32 or NTFS
• gt 32GB can only choose NTFS

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Creating a Logical Drive

• Once an Extended partition is created, you may
  create logical drives in it

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Dynamic Disks

• Dynamic Disks are a new type of storage available
  since Windows 2000
• Not available in XP Home (avail in XP Pro)
• Avail in Server 2000 and 2003
• Can convert basic to dynamic
• Converting dynamic to basic
• causes all data to be lost
• Regular drives are known as basic disks
• Dynamic disks are divided into volumes instead
  of partitions

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Dynamic Disks

• Spanning Volumes (one hard drive)
• D drive is spanned to include unallocated space
• Effect is more space on D volume

C\ Volume 10 GB
D\ Volume 10 GB
30 GB Unallocated space
C\ Volume 10 GB
D\ Volume 10 GB
30 GB Unallocated space
C\ Volume 10 GB
D\ Volume 40 GB
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Dynamic Disks

• Extended Volumes (multiple hard drives)
• Simple volume spanned across multiple disks
• Effect is more space on D volume

C\ Volume 10 GB
D\ Volume 10 GB
New Disk 80GB
C\ Volume 10 GB
D\ Volume 90 GB
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Dynamic Disks

• Simple volume like a primary partition
• Striped Volume (RAID-0)
• Mirrored Volume (RAID-1)
• Striped with Parity (RAID-5)
• Desktop products (2000 Pro, XP Pro)
• Support RAID-0
• Server products (2000 2003 Server)
• Support RAID-0, RAID-1, RAID-5

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Mount Points

• Your system partition drive (typically C) may be
  made dynamic
• Cannot be extended or spanned
• Can create a mount point on C
• Drive that functions like a folder mounted into
  another drive
• Allows adding storage to a hard drive by creating
  a folder that is another whole hard drive

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Creating Mount Points

• Alt-click an unallocated space on a dynamic disk
  and select New Volume
• The second screen in the wizard lets you create a
  mount point instead of another drive letter
• Works like folder but appears as disk icon

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Formatting a Partition

• Can do in Windows Explorer
• Can do in DiskManagement

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Maintaining and Troubleshooting Hard Drives
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ScanDisk and CHKDSK

• ScanDisk and CHKDSK check for bad clusters on
  hard drives
• Also checks for invalid file names and tries to
  fix them
• Looks for lost clusters or chains that do not
  have a filename associated with them and deletes
  them
• Checks the links between parent and child folders
• Launched via Error-Checking tools from Windows
  Explorer

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Error-Checking

• Can check the drive
• Can be set to automatically fix errors
• Can scan for andrecover badsectors

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Defragmentation

• Disk Defragmenter
• Consider using regularly (monthly or weekly)
• Will slow down system while running
• If not done, system may slow down due to
  fragmentation
• Can be scheduled

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Disk Cleanup

• Allows you to purge system of unneeded files
• Files in the Recycle Bin
• Temporary Internet Files
• Downloaded Program Files
• Temporary Files

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Troubleshooting

• Three broad categories
• Installation Errors
• Data Corruption
• Dying Hard Drives

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Troubleshooting Installation

• Connectivity
• Hard drive error
• No fixed disks present
• HDD controller failure
• NO boot device available
• Drive not found
• Solutions include
• Checking the cables to make sure they connected
  properly
• Reseating the hard drive controller (if an
  expansion card)
• Use autodetection in CMOS
• Check the jumper settings
• Some EIDE drives are incompatible on the same
  controller

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Troubleshooting Installation

• CMOS
• CMOS configuration mismatch
• No boot device available
• Drive not found
• Missing OS
• Solutions
• Always run autodetect in CMOS
• Always select LBA

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Troubleshooting Installation

• Partitions
• Failing to partition
• Invalid drive specification error
• Making the wrong size or type of partition
• Format
• Failing to format
• Drive is not accessible
• Invalid media type
• Trying to recover lost allocation unit
  indicates the drive is dying

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Troubleshooting Corruption

• Data Corruption
• Caused by many things such as power surges,
  accidental shutdowns, viruses, and more
• Show up as
• File is missing or corrupt
• Download location information is damaged
• Unable to load file
• Cannot find command.com
• Error loading operating system
• Invalid boot.ini
• Try running Error Checking utility

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Troubleshooting Corruption

• Extract/Expand
• If you need to copy a specific file from an
  installation CD, it is probably located inside a
  CAB (cabinet) file
• Corrupted data on bad sectors
• The built-in error correction code (ECC) checks
  the drive for bad sectors
• Disk checkers can be used for fixing problems
  pertaining to corrupted data

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Troubleshooting Installation

• Corrupted data on bad sectors
• The built-in error correction code (ECC) checks
  the drive for bad sectors
• Disk checkers can be used for fixing problems
  pertaining to corrupted data

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Troubleshooting Dying HD

• Dying hard drive
• The following sounds indicate a drive about to
  die
• Continuous high-pitched squeal
• Series of clacks, a short pause, and then more
  clacks
• Continuous grinding or rumbling
• Boot drive issue would show up as no boot device
  present
• Second drives simply do not show up

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Third Party Partition Tools

• Third-party partition tools allow you to create,
  change, and delete partitions without destroying
  the data
• PowerQuests Partition Magic
• VCOMs Partition Commander

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The End!!!