Implementing Hard Drives

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Implementing Hard DrivesChapter 1: Part 8


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


Hard Drive Partitions


Partitioning

• Process of electronically subdividing the physical hard drives

– Windows assigns them names such as 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


Essentials

CompTIA A+Essentials


Basic Disks

• Master boot record (MBR)– 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


Basic Disks

• Support up to four partitions– Can have four primary partitions or three primary

partitions and one extended partition

• Primary partition—bootable

• Extended partitions—non-bootable– Can hold multiple logical drives lettered D: to Z:


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: to Z:


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 currently booted to is marked as active partition


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 Chapter 9• Other volumes covered in more depth later in chapter


Other Partitions

• Hidden partition– Primary partition hidden from OS– Used to hide a backup copy of OS

• Swap partition– Only on Linux and BSD systems– Entire partition that works like page file in Windows


When to Partition

• Older OSs required partitioning before installation– Command-line program called FDISK

• Windows 2000 and above include partition tool in install program


When to Partition

• After installation– Windows 2000 and above use GUI called Disk

Management– Third-party tools available:

• GParted (Linux tool that works on Windows partitions)

• Partition Magic


Hard Drive Formatting

• Formatting configures a partition to hold files and folders suitable to the OS

• Two major functions of formatting – Creates a file system– Creates a root directory


File Systems

• Windows supports three different file systems:

– FAT16 (often called just FAT)

– FAT32

– NTFS


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 two-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


FAT Limitations

• 16 bits can address only 64 K (216) sectors

• Sector sizes limited to 512 bytes

• 64K X 512 bytes = 32 MB max size

• Solution was clustering, allowing partition sizes up to 2 GB


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 use FAT16 – Newer OSs also support FAT16


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 cluster’s number is put in the first status

field to know where to link– Process continues until the file is fully stored– Last cluster’s status field is marked FFFF (end-of-

file)


Examples of FAT Storage

1

2

3

4

0000 = Good FFF7 = Bad FFFF = End of File


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 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 such as Disk Defragmenter or Speed Disk can be used to defragment files, folders, or both


Fragmented File

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


Disk Defragmenter

• Can defragment disk


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


CompTIA A+Technician

NTFS

IT Technician


NTFS

• File system of choice today

• Six major improvementsand refinements1. Redundancy2. Security3. Compression4. Encryption5. Disk quotas6. Cluster sizing


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 you’re on the list, you’re granted the specific

permission


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


NTFS Improvements

• Disk quotas– Can control how users

can use space– Set on a per-drive basis

• Cluster sizes– Can adjust cluster sizes– Rare to do so

– NTFS supports 2 TBpartitions


Partitioning and Formatting Process


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


Partitioning and Formatting

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



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



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



• With Windows installation CD– Can create multiple partitions


PATA Drive Letter Assignments

• Primary partition of the1. Primary master drive2. Primary slave drive3. Secondary master drive4. Secondary slave drive

• Then all logical drives in the extended partition of the1. Primary master drive2. Primary slave drive3. Secondary master drive4. Secondary slave drive

C:D:E:F:


SATA Drive Letter Assignments

• Similar to PATA, but based on order set in CMOS1. Primary partition of the first drive2. Primary partition of the second drive3. Primary partition of the third drive4. Etc.

5. All logical drives in extended partition of first drive6. All logical drives in extended partition of second

drive7. All logical drives in extended partition of third

drive8. Etc.


Disk Management

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


Creating a New Partition

• Right-click in unallocated space and choose New Partition


New Partition Wizard


Disk Management

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


Creating a Logical Drive

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


Dynamic Disks

• Dynamic disks are a new type of storage available since Windows 2000 – Not available in XP Home (available in XP Pro)– Available in 2000 Server

and Server 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


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


Dynamic Disks

• Extended volumes (multiple hard drives)– Simple volume spanned across multiple disks

– Effect is more space on D: volume


New disk—80 GB



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 & Server 2003)– Support RAID 0, RAID 1, RAID 5


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

– Provides additional storage on a hard drive by creating a folder that is another entire hard drive


Creating Mount Points

• Right-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


Formatting a Partition

• Can do in Windows Explorer

• Can do in DiskManagement


Maintaining and Troubleshooting Hard Drives


ScanDisk and CHKDSK

• ScanDisk and CHKDSK check for bad clusters on hard drives– Also checks for invalid filenames 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


Error-checking

• Can check the drive

• Can be set to fix errors automatically

• Can scan for andrecover badsectors


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


Disk Cleanup

• Allows you to purge system of unneeded files

– Files in the Recycle Bin

– Temporary Internet files

– Downloaded program files

– Temporary files


Troubleshooting

• Three broad categories:

1. Installation errors

2. Data corruption

3. Dying hard drives


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



• CMOS

– CMOS configuration mismatch

– No boot device available

– Drive not found

– Missing OS

– Solutions• Always run autodetect in CMOS• Always select LBA



• 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


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


Troubleshooting Corruption

• Extract/expand

– Use to copy a specific file from an installation CD

– Many files 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 to fix problems pertaining to corrupted data


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


• Third-party partition tools allow you to create, change, and delete partitions without destroying the data

– PartitionMagic

– VCOM’s Partition Commander

Third-Party Partition Tools

Documents

Implementing Hard Drives