03[2] Disk Management
Content
Disk Management Issues Designed by www.techpings.com
Agenda Overview Disk Components Disk Architecture Disk Access Errors Recovery Console Disk Management Tools Disk Performance Disk Protection Boot Settings for Disks Designed by www.techpings.com
Objectives Upon completion of this course, the participant will be able to: Explain disk components and proper installation procedures Explain disk architecture and preparation using FDISK, FORMAT and SYS Explain CMOS settings effecting IDE/EIDE devices Optimize disk using Disk Cleanup, Compression, ScanDisk, and Defrag Manage and protect the disk using Backup and Quotas
Designed by www.techpings.com
Overview What is disk management ? The hard disk is the storage location for computer files The operating system, programs, and documents are all files that are commonly stored on the local hard disk Because the disk controller searches and stores sequentially, it is critical to optimize the disk on a regular basis and manage the space efficiently Understanding how the operating system interacts with the disk and how files are stored on the disk can ensure that files are protected and the operating system performance is optimized. Designed by www.techpings.com
Overview How do disk problems occur? Disk problems occur because of operating system activities and storage activities The Windows operating systems use the local disk when: • Paging • Downloading • Printing • Saving Designed by www.techpings.com
Overview If disk space is insufficient or fragmented when the operating system accesses it, operating system performance can be negatively affected or the system can crash Storage activities occur because the disk controller stores files sequentially As files grow over time, this process leads to fragmented files, cross-linked files, or lost clusters Many files are stored on the local hard disk that users may not be aware of Cleaning up these files and optimizing the disk regularly can keep problems from occurring Designed by www.techpings.com
Disk Components IDE vs. SCSI Bus Architecture Disks primarily come in two bus architectures IDE and SCSI ATA ( AT Attachment ) and IDE (Integrated Device Electronics) are the same Combines the disk controller with the physical disk Controller is not on the I/O card SCSI (Small Computer Systems Interface) architecture combines the disk controller and the adaptor (the SCSI card) Allows SCSI to control access to the bus by multiple devices (multiple disks) Designed by www.techpings.com
Disk Components IDE (ATA) vs. SATA SATA drives have a faster interface than normal ATA disks and can have higher duty cycles. SATA will be used where more performance than ATA disks is needed but cost is still an issue. Serial ATA (Serial Advanced Technology Attachment or SATA) is a new standard for connecting hard drives into computer systems. As its name implies, SATA is based on serial signaling technology, unlike current IDE (Integrated Drive Electronics) hard drives that use parallel signaling.
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Disk Components When bus is free it can receive commands or transfer data for another device Disk architecture choice depends on the computer device If the computer will have only one disk drive, then IDE is the best choice It is less expensive and no performance improvement will occur compared to SCSI Designed by www.techpings.com
Disk Components If the computer will support multiple devices, SCSI will offer several advantages: • Connectivity – IDE can support up to two devices on each bus, SCSI can support up to 126 devices
• Bandwidth – The SCSI bus controller manages bandwidth so more devices can have access without performance degradation
• Efficiency – SCSI provides queuing of up to 256 commands. IDE does not provide for queuing
• Reliability – SCSI can sustain higher temperatures and fluctuations and still maintain integrity Designed by www.techpings.com
Disk Components Disk Installation Hard disk installation requires the following: • • • • •
Disk Data cable Power cable Disk adaptor card Driver
ATA/IDE architecture requires a 40 or 80 pin (40 grounding wires for each sending wire) ribbon cable with 3 IDC connectors Designed by www.techpings.com
Disk Components The red strip on the data cable is used to determine proper cable installation Strip should always face the power cable The middle IDC connector should be connected to the slave drive, if needed SCSI requires a parallel interface with termination of the ends of the bus to prevent ringing Several SCSI standards, specific requirements differ slightly for each standard Designed by www.techpings.com
Disk Components Most common internal connection cable is the Type A 50 pin ribbon cable used for SCSI-1, SCSI-2, and Fast SCSI-2 Type P 68 pin connectors are also used for SCSI-2 SCSI-3 adaptors use SCA-80 80 pin cables External SCSI connectors include 50 pin Centronics (SCSI-1), 50 pin HD(High Density) D-type (SCSI-2), 68 pin HD D-type (Wide SCSI-2 and SCSI-3), and 25 pin standard D-type (SCSI-2 with Macintoshes) Designed by www.techpings.com
Disk Components The SCSI adaptor normally uses a PCI bus on the motherboard or a PCI slot
Each SCSI device on a SCSI chain must have a unique identifier
The two ends of a SCSI chain must be terminated to stop reflection
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Disk Architecture Disk Components Hard drives are composed of one or more silicon disks Cluster
• Sector –the smallest area on the disk where data is stored
• Cluster – two or more sectors used by the file system to store data
Sector
Track
• Track – circular divisions on the disk Designed by www.techpings.com
Disk Architecture Disk Preparation A disk must be prepared before information can be stored on it • Low-level formatting occurs at the manufacturer - Writes tracks and sectors to the surface of the disk - Sector size is generally 512 bytes - 0’s are written to every bit in each sector - 8 bits in each byte Designed by www.techpings.com
Disk Architecture 2. Identifying the disk for the CMOS occurs after the disk has been installed in the computer -
During boot process the disk is automatically detected or requires input in setup to recognize disk characteristics
-
OS reads the clusters
-
Clusters are two or more sectors
-
On ATA/IDE disks the BIOS cannot recognize more than 504 MB
-
To get around this limit, LBA/ECHS lies to the computer about the disk’s geometry
-
LBA (Long Block Allocation) allows the CMOS to see the logical drive geometry instead of the physical geometry
-
SCSI drives do not have physical limitations
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Disk Architecture 3. Partitioning the disk -
FDISK accomplishes this step for Windows 9x operating systems
-
In Windows NT/2000 systems, Diskpart, is part of the installation process and Disk Administrator (Windows NT) or Disk Management (Windows 2000) provide access to this tool within Windows
-
Partitioning walls off sections of a disk and assigns a drive letter to each partition
-
Partitioning process writes two important components to the 0 sector of the disk, the partition table and the Master Boot Record (MBR)
-
Partition table, keeps track of the primary, extended and logical partitions and their size, and the file system each uses
-
The MBR points to the location of the operating system files upon boot
-
They can then be loaded in memory and the boot process can continue
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Disk Architecture 4. Specify a file system by formatting the disk -
Not a low-level format
-
Formatting is specific to the file system used on the partition
-
Two types of file systems when storing a Windows OS on a partition, FAT and NTFS
-
When formatting a file, the File Allocation Table (FAT) or Master File Table (MFT) composed of metadata files (NTFS), is written to the 0 sector of the disk and a root directory structure is created
-
The file or table written to the disk contains the file names and locations on the disk
-
Formatting replaces the file/table, clearing the disk
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Disk Architecture FAT (File Allocation Table) • Can be used with Windows 9x and Windows NT/2000/XP operating systems
• FAT is a simple file system located at the top of the partition • Two FATs exist in case one becomes damaged • Provides little security for files • Attributes can be assigned to files and folders to make them read only or hidden
• Attribute applies to everyone • Partitions are limited to 2GB in Windows 9x operating systems and 4GB in Windows NT operating systems
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Disk Architecture NTFS (New Technologies File System) • NTFS is a high-performance and self-healing file system proprietary to Windows XP 2000 NT, which supports filelevel security, compression and auditing.
• It also supports large volumes and powerful storage solution such as RAID.
• The most important new feature of NTFS is the ability to encrypt files and folders to protect your sensitive data. This provides several advantages over the FAT system
• Built in recoverability tools, which ensure minimal lost clusters and cross-linked files
• Provides individual user security settings for files and folders • NTFS can access partitions as large as 16 exabytes Designed by www.techpings.com
Disk Architecture Criteria
Operating System
NTFS5
NTFS
FAT32
FAT16
Windows 2000 Windows XP
Windows NT Windows 2000 Windows XP
Windows 98 Windows ME Windows 2000 Windows XP
DOS All versions of Microsoft Windows
Limitations Max Volume Size
2TB
2TB
2TB
2GB
Max Files on Volume
Nearly Unlimited
Nearly Unlimited
Nearly Unlimited
~65000
Max File Size
Limit Only by Volume Size
Limit Only by Volume Size
4GB
2GB
Max Clusters Number
Nearly Unlimited
Nearly Unlimited
268435456
65535
Up to 255
Standard - 8.3 Extended - up to 255
Max File Name Length
Up to 255
Up to 255
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Disk Architecture Criteria
Operating System
NTFS5
NTFS
FAT32
FAT16
Windows 2000 Windows XP
Windows NT Windows 2000 Windows XP
Windows 98 Windows ME Windows 2000 Windows XP
DOS All versions of Microsoft Windows
System Character Set
System Character Set
Unicode File Names
Unicode Character Set
File System Features Unicode Character Set
System Records Mirror
MFT Mirror File
MFT Mirror File
First and Last Sectors Standard and Custom
First and Last Sectors Standard and Custom
Alternate Streams
Yes
Compression
Boot Sector Location
Second Copy of FAT Second Copy of FAT First Sector
First Sector
Standard Set
Standard Set
Yes
No
No
Yes
Yes
No
No
Encryption
Yes
No
No
No
Object Permissions
Yes
Yes
No
No
Disk Quotas
Yes
No
No
No
Sparse Files
Yes
No
No
No
Reparse Points
Yes
No
No
No
Volume Mount Points
Yes
No
No
No
File Attributes
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Disk Architecture Criteria
Operating System
NTFS5
NTFS
FAT32
FAT16
Windows 2000 Windows XP
Windows NT Windows 2000 Windows XP
Windows 98 Windows ME Windows 2000 Windows XP
DOS All versions of Microsoft Windows
Overall Performance Built-In Security
Yes
Yes
No
No
Recoverability
Yes
Yes
No
No
Performance
Low on small Volumes High on Large
Low on small volumes High on Large
High on small Volumes Low on large
Highest on small Volumes Low on large
Disk Space Economy
Max
Max
Average
Minimal on large volumes
Fault Tolerance
Max
Max
Minimal
Average
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Disk Architecture Disk is now ready to store information Partition must contain an operating system to boot The DOS operating system is easiest to install It consists of three files: • IO.sys • MSDOS.sys • Command.com
These files must be transferred to a bootable disk to notify the MBR that this is an operating system Designed by www.techpings.com
Disk Architecture When a Windows OS is installed, the MBR is updated to reflect the location of the system files
On a multi-boot disk (a disk containing more than one operating system), the MBR points to the location of the primary operating system files
If the primary operating system is Windows NT or Windows 2000, the file boot.ini will contain a mapping to other operating systems available Designed by www.techpings.com
Disk Architecture Disk Storage Processing • Files are written to the disk in sequential order • A file is written to the next open cluster on the disk • If a file is not as large as the cluster, the rest of the space is not used
• When a file is deleted, the cluster occupied by that file is now available
• Cluster will not be used until the disk is completely full or the disk is defragmented Designed by www.techpings.com
Disk Architecture • In the following example, Files A, B, and C are written to the disk clusters File A
File B
File C
• The user adds information to File A File A
File B
File C
File A
• The user writes File D to the disk File A
File B
File C
File A
File D
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Disk Architecture • The user deletes File A File A
File B
File C
File A
File D
• The user writes more information to File B File A
File B
File C
File A
File D
File B
• The space occupied by File A is not used until Defragmenter is run
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Disk Architecture • All files that are not contiguous, like File B, are put together and the deleted file spaces are overwritten
• Notice that File B is not overwritten until a new file is saved File B
File B
File B
File C
File D
File B
• When a file is requested in memory, the file is retrieved through a sequential search
• If the disk is fragmented or parts of a file are located on different clusters on the disk, the process for retrieving the file will be slow and operating system performance will be adversely affected Designed by www.techpings.com
Disk Access Errors Disk access errors occur for several reasons: • The 0 sector has been physically damaged • The MBR is missing or corrupted • The FAT or NTFS table has been corrupted • The operating system files cannot be found • A file cannot be opened
Specific errors are displayed that identify the error Troubleshooting in a timely manner may save the disk or file Designed by www.techpings.com
Disk Access Errors 0 Sector Damage Disk is no longer usable if 0 sector is physically damaged Commonly caused by ESD (Electrostatic Discharge) ESD can occur: • When installing a field replaceable component - Follow proper grounding procedures before touching the disk - Latent catastrophic failures are caused by ESD damage to the transistors on the disk or main board
• When a surge occurs at the power source. - Always use a surge protector to guard the computer system from electrical spikes and surges Designed by www.techpings.com
Disk Access Errors MBR Damage When the MBR is damaged, it no longer points to the location of operating system files Errors that may signify damage to the MBR include: • Machine language on the screen • “Rom Basic missing. System halted” • System freezes after Rom Bios checks hardware
If one of these errors occur, use FDISK /MBR to repair the MBR without changing the partition table Do not use this command if there are more than 4 partitions on the physical disk Designed by www.techpings.com
Disk Access Errors File System Unreachable If FAT is not readable, the error Missing Operating System will display Can occur if the partition containing the FAT is not marked as the active partition This can be accomplished using FDISK Can also occur when the FAT is corrupted Use the SCANDISK utility to scan the disk This tool may be able to salvage the copy of the FAT and restore access to the disk Attempt to run the Emergency Repair Process from the Emergency Repair Disk Designed by www.techpings.com
Disk Access Errors Operating System Error Non-System Disk Error occurs when boot disk contains no Error operating system files or files are corrupted Boot order for disks is set in CMOS Floppy drive is normally the first disk accessed If a non-bootable disk is in the drive, this error will be displayed Can also occur if the OS files have been damaged With Windows 9x operating systems, the basic operating system files (DOS) can be restored from a bootable floppy using the SYS command Attempt to run the Emergency Repair Process from the Emergency Repair Disk Designed by www.techpings.com
Disk Access Errors File Access Error File access errors occur because the file parts have lost pointers to one another Can be caused by disk fragmentation and by viruses When a file access error occurs, scan the disk using the Scandisk or the error checking utility in Disk Management (Windows 2000) Attempt to run the Emergency Repair Process from the Emergency Repair Disk Designed by www.techpings.com
Recovery Console Recovery Console is a command line utility similar to MS-DOS command line. You can list and display folder content, copy, delete, replace files, format drives and perform many other administrative tasks. To run Recovery Console, boot from Windows bootable disks or CD and choose Repair option, when system suggests you to proceed with installation or repairing. Press C to run Recovery Console. Designed by www.techpings.com
Recovery Console You will be asked which system you want to log on to and then for Administrator's password. After you logged on you can display drive's contents, check the existence and safety of critical files and, copy them back if they have been accidentally deleted (see graphic). Designed by www.techpings.com
Disk Management Tools Disk Cleanup • Disk Cleanup should always be performed before scanning the disk or defragmenting
• When disk space is limited, Disk Cleanup points to the location of common files that can be deleted or compressed
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Disk Management Tools • Many files are saved to the disk without the user’s specific request or approval
• Temporary Internet files are downloaded every time you access a web site
• Temporary files are created during the printing process, while working on certain types of documents, and during unexpected shutdowns while working on documents
• Downloaded programs are support components that are automatically downloaded to support a web site the user opens
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Disk Management Tools • When a file is deleted, it is sent to the Recycle Bin, which is just another location on the hard drive
• Disk Cleanup provides the user with a single tool to delete or compress all files on the disk
• The More Options tab provides access to remove Windows components not being used and/or to remove installed programs no longer in use Designed by www.techpings.com
Disk Management Tools Computer Management • Partitions can be created, formatted and deleted from this screen
• Shows which file system the disk has been formatted with
• A FAT partition cannot see an NTFS partition on the same computer
• An NTFS partition can see both FAT and NTFS partitions Designed by www.techpings.com
Disk Management Tools Disk Properties • The following screen can also be reached following these steps: - Double-click My Computer on the Desktop - Right -click a partition and click Properties
• Click the Quota tab to set disk quotas for users
• This can keep users from saving too much to the limited space on a disk Designed by www.techpings.com
Disk Management Tools Error Checking • Scans the disk for errors and compares the contents with the listing in the file table
• Looking for file system errors and errors on the disk • If bad cluster is found, cluster is marked and the disk controller will no longer attempt to save information to it
• Fragments on the disk cause file system errors • Cross-linked files occur when pointers in two files point to the same location
• Lost clusters occur when clusters are not correctly marked as containing information or as being available for information Designed by www.techpings.com
Disk Management Tools Defragment • Tool used to move files into contiguous order on the disk
• Fragmented files are put into contiguous order
• Space taken by deleted files is written over
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Disk Performance Performance Monitor • Tool used to monitor resources over time
• Monitoring physical disk components and paging file components provides information to direct troubleshooting efforts
• Resources to monitor can be added Designed by www.techpings.com
Disk Performance Paging File Settings • Paging File is space on the physical disk set aside to act like memory
• While the operating system is managing the computer resources, it swaps 64K pages to the location of the paging file on the disk
• The Least Recently Used (LRU) files are swapped • A page resides briefly on the page file • It is then brought back to physical memory and another page is swapped
• The page file should be at least 1.5 times actual memory and should be a static file
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Disk Performance
• The paging file can be updated
• The computer will have to be rebooted after changing the paging file size
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Disk Protection Disk Backup Disks fail! There is no substitute for a backup • A full backup copies everything in the designated folders • An incremental backup makes a copy of only the files that have changed since the last backup of the designated folders
• A differential backup is a copy of the files that have changed since the last backup but does not turn the archive attribute to OFF - The next differential backup will copy some of the same files it copied during the original backup Designed by www.techpings.com
Disk Protection Electrostatic Discharge (ESD) • Disks can be destroyed by ESD • A UPS protects a disk from surges and brownouts • Both of these issues can cause problems for a disk • When working with a disk, wear an electrostatic strap and place the disk on a rubber mat
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Boot Settings for Disks Physical disk boot settings are controlled in CMOS and in the boot.ini file CMOS • Access the CMOS settings during the bootstrap phase of the boot process
• This is where CMOS settings are modified • Boot drive order can be changed here • The options are the CD-ROM, disk, or floppy drive • A bootable drive is one that contains an operating system Designed by www.techpings.com
Boot Settings for Disks Boot.ini • If more than one operating system is on a computer, the boot.ini file can be modified to boot to a different partition if the boot partition becomes corrupted
• File is always located in the first partition on the first disk • Notepad is a text editor, and can be used to make changes • Adds no format characters that the operating system cannot read
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Boot Settings for Disks Timeout setting controls the time the operating system selection page appears during the boot process Default line points to the disk and partition that contains the operating system the computer boots to OS section lists all the operating systems that are loaded on the computer ATTRIB command will remove attributes of hidden files Designed by www.techpings.com
Boot Settings for Disks If the boot operating system crashes, boot to a bootable floppy disk or CD
Edit the boot.ini file
Under the operating system heading choose an operating system other than the boot system
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Objectives Revisited Explain disk components and proper installation procedures Explain disk architecture and preparation using FDISK, FORMAT and SYS Explain CMOS settings effecting IDE/EIDE devices Optimize disk using Disk Cleanup, Compression, ScanDisk, and Defrag Manage and protect the disk using Backup, and Quotas
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Review
Review / Questions
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Agenda Overview Disk Components Disk Architecture Disk Access Errors Recovery Console Disk Management Tools Disk Performance Disk Protection Boot Settings for Disks Designed by www.techpings.com
Objectives Upon completion of this course, the participant will be able to: Explain disk components and proper installation procedures Explain disk architecture and preparation using FDISK, FORMAT and SYS Explain CMOS settings effecting IDE/EIDE devices Optimize disk using Disk Cleanup, Compression, ScanDisk, and Defrag Manage and protect the disk using Backup and Quotas
Designed by www.techpings.com
Overview What is disk management ? The hard disk is the storage location for computer files The operating system, programs, and documents are all files that are commonly stored on the local hard disk Because the disk controller searches and stores sequentially, it is critical to optimize the disk on a regular basis and manage the space efficiently Understanding how the operating system interacts with the disk and how files are stored on the disk can ensure that files are protected and the operating system performance is optimized. Designed by www.techpings.com
Overview How do disk problems occur? Disk problems occur because of operating system activities and storage activities The Windows operating systems use the local disk when: • Paging • Downloading • Printing • Saving Designed by www.techpings.com
Overview If disk space is insufficient or fragmented when the operating system accesses it, operating system performance can be negatively affected or the system can crash Storage activities occur because the disk controller stores files sequentially As files grow over time, this process leads to fragmented files, cross-linked files, or lost clusters Many files are stored on the local hard disk that users may not be aware of Cleaning up these files and optimizing the disk regularly can keep problems from occurring Designed by www.techpings.com
Disk Components IDE vs. SCSI Bus Architecture Disks primarily come in two bus architectures IDE and SCSI ATA ( AT Attachment ) and IDE (Integrated Device Electronics) are the same Combines the disk controller with the physical disk Controller is not on the I/O card SCSI (Small Computer Systems Interface) architecture combines the disk controller and the adaptor (the SCSI card) Allows SCSI to control access to the bus by multiple devices (multiple disks) Designed by www.techpings.com
Disk Components IDE (ATA) vs. SATA SATA drives have a faster interface than normal ATA disks and can have higher duty cycles. SATA will be used where more performance than ATA disks is needed but cost is still an issue. Serial ATA (Serial Advanced Technology Attachment or SATA) is a new standard for connecting hard drives into computer systems. As its name implies, SATA is based on serial signaling technology, unlike current IDE (Integrated Drive Electronics) hard drives that use parallel signaling.
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Disk Components When bus is free it can receive commands or transfer data for another device Disk architecture choice depends on the computer device If the computer will have only one disk drive, then IDE is the best choice It is less expensive and no performance improvement will occur compared to SCSI Designed by www.techpings.com
Disk Components If the computer will support multiple devices, SCSI will offer several advantages: • Connectivity – IDE can support up to two devices on each bus, SCSI can support up to 126 devices
• Bandwidth – The SCSI bus controller manages bandwidth so more devices can have access without performance degradation
• Efficiency – SCSI provides queuing of up to 256 commands. IDE does not provide for queuing
• Reliability – SCSI can sustain higher temperatures and fluctuations and still maintain integrity Designed by www.techpings.com
Disk Components Disk Installation Hard disk installation requires the following: • • • • •
Disk Data cable Power cable Disk adaptor card Driver
ATA/IDE architecture requires a 40 or 80 pin (40 grounding wires for each sending wire) ribbon cable with 3 IDC connectors Designed by www.techpings.com
Disk Components The red strip on the data cable is used to determine proper cable installation Strip should always face the power cable The middle IDC connector should be connected to the slave drive, if needed SCSI requires a parallel interface with termination of the ends of the bus to prevent ringing Several SCSI standards, specific requirements differ slightly for each standard Designed by www.techpings.com
Disk Components Most common internal connection cable is the Type A 50 pin ribbon cable used for SCSI-1, SCSI-2, and Fast SCSI-2 Type P 68 pin connectors are also used for SCSI-2 SCSI-3 adaptors use SCA-80 80 pin cables External SCSI connectors include 50 pin Centronics (SCSI-1), 50 pin HD(High Density) D-type (SCSI-2), 68 pin HD D-type (Wide SCSI-2 and SCSI-3), and 25 pin standard D-type (SCSI-2 with Macintoshes) Designed by www.techpings.com
Disk Components The SCSI adaptor normally uses a PCI bus on the motherboard or a PCI slot
Each SCSI device on a SCSI chain must have a unique identifier
The two ends of a SCSI chain must be terminated to stop reflection
Designed by www.techpings.com
Disk Architecture Disk Components Hard drives are composed of one or more silicon disks Cluster
• Sector –the smallest area on the disk where data is stored
• Cluster – two or more sectors used by the file system to store data
Sector
Track
• Track – circular divisions on the disk Designed by www.techpings.com
Disk Architecture Disk Preparation A disk must be prepared before information can be stored on it • Low-level formatting occurs at the manufacturer - Writes tracks and sectors to the surface of the disk - Sector size is generally 512 bytes - 0’s are written to every bit in each sector - 8 bits in each byte Designed by www.techpings.com
Disk Architecture 2. Identifying the disk for the CMOS occurs after the disk has been installed in the computer -
During boot process the disk is automatically detected or requires input in setup to recognize disk characteristics
-
OS reads the clusters
-
Clusters are two or more sectors
-
On ATA/IDE disks the BIOS cannot recognize more than 504 MB
-
To get around this limit, LBA/ECHS lies to the computer about the disk’s geometry
-
LBA (Long Block Allocation) allows the CMOS to see the logical drive geometry instead of the physical geometry
-
SCSI drives do not have physical limitations
Designed by www.techpings.com
Disk Architecture 3. Partitioning the disk -
FDISK accomplishes this step for Windows 9x operating systems
-
In Windows NT/2000 systems, Diskpart, is part of the installation process and Disk Administrator (Windows NT) or Disk Management (Windows 2000) provide access to this tool within Windows
-
Partitioning walls off sections of a disk and assigns a drive letter to each partition
-
Partitioning process writes two important components to the 0 sector of the disk, the partition table and the Master Boot Record (MBR)
-
Partition table, keeps track of the primary, extended and logical partitions and their size, and the file system each uses
-
The MBR points to the location of the operating system files upon boot
-
They can then be loaded in memory and the boot process can continue
Designed by www.techpings.com
Disk Architecture 4. Specify a file system by formatting the disk -
Not a low-level format
-
Formatting is specific to the file system used on the partition
-
Two types of file systems when storing a Windows OS on a partition, FAT and NTFS
-
When formatting a file, the File Allocation Table (FAT) or Master File Table (MFT) composed of metadata files (NTFS), is written to the 0 sector of the disk and a root directory structure is created
-
The file or table written to the disk contains the file names and locations on the disk
-
Formatting replaces the file/table, clearing the disk
Designed by www.techpings.com
Disk Architecture FAT (File Allocation Table) • Can be used with Windows 9x and Windows NT/2000/XP operating systems
• FAT is a simple file system located at the top of the partition • Two FATs exist in case one becomes damaged • Provides little security for files • Attributes can be assigned to files and folders to make them read only or hidden
• Attribute applies to everyone • Partitions are limited to 2GB in Windows 9x operating systems and 4GB in Windows NT operating systems
Designed by www.techpings.com
Disk Architecture NTFS (New Technologies File System) • NTFS is a high-performance and self-healing file system proprietary to Windows XP 2000 NT, which supports filelevel security, compression and auditing.
• It also supports large volumes and powerful storage solution such as RAID.
• The most important new feature of NTFS is the ability to encrypt files and folders to protect your sensitive data. This provides several advantages over the FAT system
• Built in recoverability tools, which ensure minimal lost clusters and cross-linked files
• Provides individual user security settings for files and folders • NTFS can access partitions as large as 16 exabytes Designed by www.techpings.com
Disk Architecture Criteria
Operating System
NTFS5
NTFS
FAT32
FAT16
Windows 2000 Windows XP
Windows NT Windows 2000 Windows XP
Windows 98 Windows ME Windows 2000 Windows XP
DOS All versions of Microsoft Windows
Limitations Max Volume Size
2TB
2TB
2TB
2GB
Max Files on Volume
Nearly Unlimited
Nearly Unlimited
Nearly Unlimited
~65000
Max File Size
Limit Only by Volume Size
Limit Only by Volume Size
4GB
2GB
Max Clusters Number
Nearly Unlimited
Nearly Unlimited
268435456
65535
Up to 255
Standard - 8.3 Extended - up to 255
Max File Name Length
Up to 255
Up to 255
Designed by www.techpings.com
Disk Architecture Criteria
Operating System
NTFS5
NTFS
FAT32
FAT16
Windows 2000 Windows XP
Windows NT Windows 2000 Windows XP
Windows 98 Windows ME Windows 2000 Windows XP
DOS All versions of Microsoft Windows
System Character Set
System Character Set
Unicode File Names
Unicode Character Set
File System Features Unicode Character Set
System Records Mirror
MFT Mirror File
MFT Mirror File
First and Last Sectors Standard and Custom
First and Last Sectors Standard and Custom
Alternate Streams
Yes
Compression
Boot Sector Location
Second Copy of FAT Second Copy of FAT First Sector
First Sector
Standard Set
Standard Set
Yes
No
No
Yes
Yes
No
No
Encryption
Yes
No
No
No
Object Permissions
Yes
Yes
No
No
Disk Quotas
Yes
No
No
No
Sparse Files
Yes
No
No
No
Reparse Points
Yes
No
No
No
Volume Mount Points
Yes
No
No
No
File Attributes
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Disk Architecture Criteria
Operating System
NTFS5
NTFS
FAT32
FAT16
Windows 2000 Windows XP
Windows NT Windows 2000 Windows XP
Windows 98 Windows ME Windows 2000 Windows XP
DOS All versions of Microsoft Windows
Overall Performance Built-In Security
Yes
Yes
No
No
Recoverability
Yes
Yes
No
No
Performance
Low on small Volumes High on Large
Low on small volumes High on Large
High on small Volumes Low on large
Highest on small Volumes Low on large
Disk Space Economy
Max
Max
Average
Minimal on large volumes
Fault Tolerance
Max
Max
Minimal
Average
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Disk Architecture Disk is now ready to store information Partition must contain an operating system to boot The DOS operating system is easiest to install It consists of three files: • IO.sys • MSDOS.sys • Command.com
These files must be transferred to a bootable disk to notify the MBR that this is an operating system Designed by www.techpings.com
Disk Architecture When a Windows OS is installed, the MBR is updated to reflect the location of the system files
On a multi-boot disk (a disk containing more than one operating system), the MBR points to the location of the primary operating system files
If the primary operating system is Windows NT or Windows 2000, the file boot.ini will contain a mapping to other operating systems available Designed by www.techpings.com
Disk Architecture Disk Storage Processing • Files are written to the disk in sequential order • A file is written to the next open cluster on the disk • If a file is not as large as the cluster, the rest of the space is not used
• When a file is deleted, the cluster occupied by that file is now available
• Cluster will not be used until the disk is completely full or the disk is defragmented Designed by www.techpings.com
Disk Architecture • In the following example, Files A, B, and C are written to the disk clusters File A
File B
File C
• The user adds information to File A File A
File B
File C
File A
• The user writes File D to the disk File A
File B
File C
File A
File D
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Disk Architecture • The user deletes File A File A
File B
File C
File A
File D
• The user writes more information to File B File A
File B
File C
File A
File D
File B
• The space occupied by File A is not used until Defragmenter is run
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Disk Architecture • All files that are not contiguous, like File B, are put together and the deleted file spaces are overwritten
• Notice that File B is not overwritten until a new file is saved File B
File B
File B
File C
File D
File B
• When a file is requested in memory, the file is retrieved through a sequential search
• If the disk is fragmented or parts of a file are located on different clusters on the disk, the process for retrieving the file will be slow and operating system performance will be adversely affected Designed by www.techpings.com
Disk Access Errors Disk access errors occur for several reasons: • The 0 sector has been physically damaged • The MBR is missing or corrupted • The FAT or NTFS table has been corrupted • The operating system files cannot be found • A file cannot be opened
Specific errors are displayed that identify the error Troubleshooting in a timely manner may save the disk or file Designed by www.techpings.com
Disk Access Errors 0 Sector Damage Disk is no longer usable if 0 sector is physically damaged Commonly caused by ESD (Electrostatic Discharge) ESD can occur: • When installing a field replaceable component - Follow proper grounding procedures before touching the disk - Latent catastrophic failures are caused by ESD damage to the transistors on the disk or main board
• When a surge occurs at the power source. - Always use a surge protector to guard the computer system from electrical spikes and surges Designed by www.techpings.com
Disk Access Errors MBR Damage When the MBR is damaged, it no longer points to the location of operating system files Errors that may signify damage to the MBR include: • Machine language on the screen • “Rom Basic missing. System halted” • System freezes after Rom Bios checks hardware
If one of these errors occur, use FDISK /MBR to repair the MBR without changing the partition table Do not use this command if there are more than 4 partitions on the physical disk Designed by www.techpings.com
Disk Access Errors File System Unreachable If FAT is not readable, the error Missing Operating System will display Can occur if the partition containing the FAT is not marked as the active partition This can be accomplished using FDISK Can also occur when the FAT is corrupted Use the SCANDISK utility to scan the disk This tool may be able to salvage the copy of the FAT and restore access to the disk Attempt to run the Emergency Repair Process from the Emergency Repair Disk Designed by www.techpings.com
Disk Access Errors Operating System Error Non-System Disk Error occurs when boot disk contains no Error operating system files or files are corrupted Boot order for disks is set in CMOS Floppy drive is normally the first disk accessed If a non-bootable disk is in the drive, this error will be displayed Can also occur if the OS files have been damaged With Windows 9x operating systems, the basic operating system files (DOS) can be restored from a bootable floppy using the SYS command Attempt to run the Emergency Repair Process from the Emergency Repair Disk Designed by www.techpings.com
Disk Access Errors File Access Error File access errors occur because the file parts have lost pointers to one another Can be caused by disk fragmentation and by viruses When a file access error occurs, scan the disk using the Scandisk or the error checking utility in Disk Management (Windows 2000) Attempt to run the Emergency Repair Process from the Emergency Repair Disk Designed by www.techpings.com
Recovery Console Recovery Console is a command line utility similar to MS-DOS command line. You can list and display folder content, copy, delete, replace files, format drives and perform many other administrative tasks. To run Recovery Console, boot from Windows bootable disks or CD and choose Repair option, when system suggests you to proceed with installation or repairing. Press C to run Recovery Console. Designed by www.techpings.com
Recovery Console You will be asked which system you want to log on to and then for Administrator's password. After you logged on you can display drive's contents, check the existence and safety of critical files and, copy them back if they have been accidentally deleted (see graphic). Designed by www.techpings.com
Disk Management Tools Disk Cleanup • Disk Cleanup should always be performed before scanning the disk or defragmenting
• When disk space is limited, Disk Cleanup points to the location of common files that can be deleted or compressed
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Disk Management Tools • Many files are saved to the disk without the user’s specific request or approval
• Temporary Internet files are downloaded every time you access a web site
• Temporary files are created during the printing process, while working on certain types of documents, and during unexpected shutdowns while working on documents
• Downloaded programs are support components that are automatically downloaded to support a web site the user opens
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Disk Management Tools • When a file is deleted, it is sent to the Recycle Bin, which is just another location on the hard drive
• Disk Cleanup provides the user with a single tool to delete or compress all files on the disk
• The More Options tab provides access to remove Windows components not being used and/or to remove installed programs no longer in use Designed by www.techpings.com
Disk Management Tools Computer Management • Partitions can be created, formatted and deleted from this screen
• Shows which file system the disk has been formatted with
• A FAT partition cannot see an NTFS partition on the same computer
• An NTFS partition can see both FAT and NTFS partitions Designed by www.techpings.com
Disk Management Tools Disk Properties • The following screen can also be reached following these steps: - Double-click My Computer on the Desktop - Right -click a partition and click Properties
• Click the Quota tab to set disk quotas for users
• This can keep users from saving too much to the limited space on a disk Designed by www.techpings.com
Disk Management Tools Error Checking • Scans the disk for errors and compares the contents with the listing in the file table
• Looking for file system errors and errors on the disk • If bad cluster is found, cluster is marked and the disk controller will no longer attempt to save information to it
• Fragments on the disk cause file system errors • Cross-linked files occur when pointers in two files point to the same location
• Lost clusters occur when clusters are not correctly marked as containing information or as being available for information Designed by www.techpings.com
Disk Management Tools Defragment • Tool used to move files into contiguous order on the disk
• Fragmented files are put into contiguous order
• Space taken by deleted files is written over
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Disk Performance Performance Monitor • Tool used to monitor resources over time
• Monitoring physical disk components and paging file components provides information to direct troubleshooting efforts
• Resources to monitor can be added Designed by www.techpings.com
Disk Performance Paging File Settings • Paging File is space on the physical disk set aside to act like memory
• While the operating system is managing the computer resources, it swaps 64K pages to the location of the paging file on the disk
• The Least Recently Used (LRU) files are swapped • A page resides briefly on the page file • It is then brought back to physical memory and another page is swapped
• The page file should be at least 1.5 times actual memory and should be a static file
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Disk Performance
• The paging file can be updated
• The computer will have to be rebooted after changing the paging file size
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Disk Protection Disk Backup Disks fail! There is no substitute for a backup • A full backup copies everything in the designated folders • An incremental backup makes a copy of only the files that have changed since the last backup of the designated folders
• A differential backup is a copy of the files that have changed since the last backup but does not turn the archive attribute to OFF - The next differential backup will copy some of the same files it copied during the original backup Designed by www.techpings.com
Disk Protection Electrostatic Discharge (ESD) • Disks can be destroyed by ESD • A UPS protects a disk from surges and brownouts • Both of these issues can cause problems for a disk • When working with a disk, wear an electrostatic strap and place the disk on a rubber mat
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Boot Settings for Disks Physical disk boot settings are controlled in CMOS and in the boot.ini file CMOS • Access the CMOS settings during the bootstrap phase of the boot process
• This is where CMOS settings are modified • Boot drive order can be changed here • The options are the CD-ROM, disk, or floppy drive • A bootable drive is one that contains an operating system Designed by www.techpings.com
Boot Settings for Disks Boot.ini • If more than one operating system is on a computer, the boot.ini file can be modified to boot to a different partition if the boot partition becomes corrupted
• File is always located in the first partition on the first disk • Notepad is a text editor, and can be used to make changes • Adds no format characters that the operating system cannot read
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Boot Settings for Disks Timeout setting controls the time the operating system selection page appears during the boot process Default line points to the disk and partition that contains the operating system the computer boots to OS section lists all the operating systems that are loaded on the computer ATTRIB command will remove attributes of hidden files Designed by www.techpings.com
Boot Settings for Disks If the boot operating system crashes, boot to a bootable floppy disk or CD
Edit the boot.ini file
Under the operating system heading choose an operating system other than the boot system
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Objectives Revisited Explain disk components and proper installation procedures Explain disk architecture and preparation using FDISK, FORMAT and SYS Explain CMOS settings effecting IDE/EIDE devices Optimize disk using Disk Cleanup, Compression, ScanDisk, and Defrag Manage and protect the disk using Backup, and Quotas
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Review
Review / Questions
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