Transcript HardDrive - UT Computer Science

IDE and SCSI Devices
Terms and Definitions
Chapter Objectives
After completing this chapter you will:
• Understand hard drive terminology.
• Understand the different hard drive types.
• Be able to set up and configure different types of hard drives.
• Be able to troubleshoot hard drive problems.
• Understand and be able to perform hard drive preventive maintenance.
Hard Drive Overview
• Hard drives are the most popular devices for storing data. The hard drive
subsystem can have up to three parts:
– The hard drive
– Cables that attach to an adapter or the motherboard
– Control circuits located on an adapter or the motherboard
Hard Drive Geometry
• Components of a Hard Drive:
– Platters are multiple hard metal surfaces contained in the hard drive.
– Read/Write Heads write and read 1s and 0s to and from the hard drive
surface.
• A Head Crash occurs when a read/write head touches the hard drive
platter.
– Track is a concentric circle on a formatted floppy or hard drive platter.
– Cylinder is one corresponding track on all surfaces of a hard drive.
– Sectors – Each track is divided into sectors which contains 512 bytes of data.
• ZBR (Zone Bit Recording) efficiently uses the hard drive surface by
placing more sectors on the outer tracks than on the inner tracks.
• Interleaving is a method of numbering sectors for the most efficient
transfer of data between the hard drive and the controller. Today’s hard
drives normally use a 1:1 interleave.
Hard Drive Geometry
Hard Drive Geometry
IDE/SCSI – Figure #1
Hard Drive Geometry
Cylinder vs Tracks
IDE/SCSI – Figure #2
Hard Drive Geometry
Sectors on Older Hard Drives
IDE/SCSI – Figure #3
Hard Drive Geometry
Zone Bit Recording Sectors
IDE/SCSI – Figure #4
Hard Drive Geometry
3:1 Interleaving
IDE/SCSI – Figure #5
Hard Drive Interfaces Overview
• There are four hard drive interfaces:
– ST506
– ESDI
– IDE (ATA)
– SCSI
• Encoding is the way 1s and 0s are placed on the drive.
IDE (Integrated Drive Electronics)
•
IDE (Integrated Drive Electronics) is the most popular type of hard drive used in home
and business computers.
– DMA (Direct Memory Access) allows data transfer between the hard drive and RAM
without going through the CPU.
– PIO (Programmed Input/Output) is a speed standard for data transfers to and from
the hard drive.
– UDMA (Ultra DMA) allows the IDE interface to control the PCI bus for faster transfers.
– SMART (Self-Monitoring Analysis & Report Technology) is part of the ATA-3 IDE
standard for power management, drive analysis, and failure reporting.
– CRC (Cyclic Redundancy Checking) is an advanced method of checking the data for
errors.
– ATAPI (AT Attachment Packet Interface) is the hardware side of the IDE specification
that supports devices like CD and tape drives.
– Serial ATA is a point to point interface in which each device connects to the host
through a dedicated link and has the entire interface bandwidth.
IDE (Integrated Drive Electronics)
PIO Modes for IDE Hard Drives
IDE/SCSI – Table #1
IDE (Integrated Drive Electronics)
DMA Modes for IDE Hard Drives
IDE/SCSI – Table #2
IDE (Integrated Drive Electronics)
80 and 40 Pin Conductor Cable
IDE/SCSI – Figure #6
IDE (Integrated Drive Electronics)
IDE ATA Standards
IDE/SCSI – Table #4
SCSI (Small Computer System Interface)
• SCSI (Small Computer System Interface) is an interface standard that
connects multiple small devices to the same adapter via a SCSI bus.
– SCSI bus is the bus shared by all devices that attach to one SCSI
adapter.
– Host Adapter connects the SCSI device to the motherboard and
coordinates the activities of other devices connected.
SCSI (Small Computer System Interface)
SCSI Standards
IDE/SCSI – Table #5
Laptop Storage Devices
• Laptops can use IDE or SCSI hard drives.
• Laptop IDE hard drives are installed using two methods:
– Proprietary installation is installed in a location that cannot be
changed, configured, or moved very easily.
– Removable IDE hard drives with a laptop are installed or removed
through a 44-pin connector.
SCSI Software Standards
• Most SCSI hard drives have software built into the hard drive’s BIOS
chip. Other drives must use one of three types of SCSI software
standards:
– ASPI (Advanced SCSI Programming Interface)
– CAM (Common Access Method)
– LADDR (Layered Device Driver Architecture)
Drive Configuration Overview
• The configuration of a hard drive usually includes setting jumpers on the
drive, terminating properly, and performing a few software commands.
IDE Device Configuration
• IDE Hard Drives are normally configured using jumpers.
– Single IDE setting is used when only one devices connects to the IDE cable.
– Master IDE setting is a jumper setting used to configure an IDE device and is
the controlling device on the interface.
– Slave IDE setting is an IDE setting for the second device added to the IDE
cable. The device should be a slower device than the master.
– Cable Select is a setting used on IDE devices when a special cable
determines which device is the master and which one is the slave.
– DASP (Drive Active/Slave Present) is a signal in the ATA interface of the IDE
connector that is used to indicate the presence of a slave IDE device.
– Master/Slave configuration can be found on 9-19.
IDE Device Configuration
IDE Motherboard Connectors
IDE/SCSI – Figure #7
IDE Device Configuration
IDE Hard Drive Set as Master
IDE/SCSI – Figure #8
IDE Device Configuration
Two IDE Hard Drives
IDE/SCSI – Figure #9
Serial ATA (SATA) Installation
• Serial ATA drives are easy to install.
– Serial ATA drives do not have any master/slave, cable select, or
termination settings
– Uses a small 7-pin connector that attaches between the serial ATA
controller and the serial ATA drive
• Installation instructions for serial ATA drives can be found on 9-25.
Serial ATA (SATA) Installation
Installed SATA Hard Drive and Adapter
IDE/SCSI – Figure #12
SCSI Configuration
• A SCSI device is configured by:
– Setting the proper SCSI ID
– Terminating both ends of the SCSI chain
– Connecting the proper cables
• A SCSI ID is the priority number assigned to each device connected by a
SCSI chain.
SCSI ID Configuration
• Standard SCSI devices recognize SCSI IDs 0 through 7.
• Wide SCSI devices recognize SCSI IDs 0 through 15.
• Power on all external SCSI devices before powering on the computer.
• Each SCSI device must have a unique SCSI ID.
– SCAM (SCSI Configured AutoMatically) allows for automatic SCSI
ID assignment.
SCSI ID Configuration
SCSI ID Settings (Most Significant Bit to the Left)
IDE/SCSI – Table #7
SCSI ID Configuration
Two Internal SCSI Devices – SCSI IDs
IDE/SCSI – Figure #13
SCSI ID Configuration
Two External SCSI Devices – SCSI IDs
IDE/SCSI – Figure #14
SCSI Termination
•
SCSI termination is performed in several different ways:
– By installing a SIPP
– By installing a jumper
– By setting a switch
– By installing a terminator plug
– By installing a pass-through terminator
– Through software
SCSI Termination
•
The SCSI bus cannot operate properly without terminating both ends of the SCSI bus.
– SE (Single Ended) is a type of SCSI electrical signal and terminator used with most SCSI devices.
– Passive Terminators are one type of SCSI chain end that is susceptible to noise interference over
long cable distances. It is used with SCSI-1 devices.
– Active Terminators are a type of end to a SCSI chain that allows for longer cable distance and
provides correct voltage for SCSI signals.
– FPT (Forced Perfect Termination) is a special type of active terminator that can be used with SE
devices.
– HVD (High Voltage Differential) is a SCSI-2 standard that allowed longer SCSI bus lengths and
required a differential terminator. HVD was removed from the SCSI-3 standards.
– Differential Terminator is a SCSI terminator used with HVD SCSI devices. It cannot be used with
other SCSI types.
– LVD (Low Voltage Differential) is a SCSI signaling type that is required on all SCSI devices that
adhere to the Ultra SCSI standards. LVD is backwards compatible with SE.
– Pass Through Terminator allows a device that does not have terminators to be terminated through
the connector that attaches to the cable.
SCSI Termination
SCSI Termination
IDE/SCSI – Figure #15
SCSI Termination
Today’s SCSI Terminators:
Pass Through Terminator and 68-Pin Active Terminator
IDE/SCSI – Figure #17
SCSI Termination
SCSI Symbols
IDE/SCSI – Figure #19
SCSI Termination
Two Internal SCSI Devices - Termination
IDE/SCSI – Figure #20
SCSI Termination
Two External SCSI Devices - Termination
IDE/SCSI – Figure #21
SCSI Termination
Internal and External SCSI Devices - Termination
IDE/SCSI – Figure #22
SCSI Cables
• SCSI cabling allows multiple devices to be connected to one SCSI host
adapter and share the same SCSI bus.
– Most internal SCSI-1 and SCSI-2 cables are 50-pin ribbon cables.
They are also known as an A cable.
– Internal SCSI-3 cables are 68-pin ribbon cables.
• When installing multiple SCSI devices, install one device at a time.
• Always avoid using the cheaper, thinner SCSI cables. They are more
susceptible to outside noise.
SCSI Cables
Internal SCSI Cables
IDE/SCSI – Figure #23
SCSI Cables
External SCSI Cables
IDE/SCSI – Figure #24
SCSI Cables
SCSI Cables and Connectors
IDE/SCSI – Table #9
System Configuration for Hard Drives
• Hard drives are configured through the Setup program with a drive type
number.
– Drive Type is a number that corresponds to a drive’s geometry (the
number of cylinders, heads, and sectors).
– IDE hard drives are normally configured using the Auto-Detect feature
included with BIOS. This feature automatically determines the drive
type for the system.
BIOS Configurations for Hard Drives
• Most system BIOS chips manufactured before 1994 use INT13 to
recognize hard drives up to 504MB.
– INT13 Interface or Interrupt 13 is a standard that allows a system
BIOS to locate data on the hard drive.
– LBA (Logical Block Addressing) allows hard drives to be
recognized up to 8GB in capacity.
– Extended INT13 Interface can support drives larger than 8GB in
capacity.
Hard Drive Preparation Overview
• Three steps to hard drive preparation:
– Low-Level Format
– Partition
– High-Level Format
Partitioning
• Partitioning divides a hard drive so that the computer system sees more than
one drive.
– FDISK is a command used to partition a hard drive.
• A File System defines how data is stored on a drive.
– FAT (File Allocation Table) is a method of organizing a computer’s file
system.
– FAT16 file system is supported by DOS, Windows 9x, NT, 2000, and XP.
– FAT32 file system used by Windows 95 Service Release 2, Windows 98,
Windows 2000, and XP that supports hard drives up to 2TB in size.
– NTFS (NT File System) file system used with Windows NT, 2000, and XP.
Partitioning
• Types of Partitions:
– The Primary Partition is the first detected drive on the hard drive.
– The Extended Partition is a hard drive division
– Logical Drives divides the extended partition into separate units which
appear as separate drive letters.
– System Partition is a type of active hard drive partition found in Windows NT
and 2000 that contains the hardware-specific files needed to load the
operating system.
– Boot Partition – A type of partition found in Windows NT and 2000 that
contains the operating system.
• The Partition Table holds the information about the types and locations of
partitions created. It is part of the master boot record.
• MBR (Master Boot Record) is a program that reads the partition table to find the
primary partitions used to boot the system.
Partitioning
Clusters
IDE/SCSI – Figure #25
Partitioning
FAT16 Partitions and Cluster Size
IDE/SCSI – Table #12
Partitioning
FAT32 Partitions and Cluster Size
IDE/SCSI – Table #13
Partitioning
NTFS Partitions and Cluster Size
IDE/SCSI – Table #14
Partitioning
NT Disk Administrator
IDE/SCSI – Figure #26
Partitioning
Hard Drive Partitioning
IDE/SCSI – Figure #27
Partitioning
Two Logical Drives
IDE/SCSI – Figure #28
How Drive Letters Are Assigned
• The order in which the partitions are assigned drive letters depends on
three factors:
– The number of hard drives
– The type of partitions on the hard drives
– The operating system
• The first floppy drive detected is assigned drive letter A:.
• The second floppy drive detected is assigned drive letter B:.
• The first hard drive primary partition detected receives drive letter C:.
• Drive letters assigned after letter C: are dependent upon the operating
system installed.
How Drive Letters Are Assigned
Logical Drive Letters with Two Hard Drives
IDE/SCSI – Figure #30
Windows 2000/XP Logical Disk Management
• Windows 2000 and XP have two types of storage: Basic and Dynamic.
– Basic Storage is a Windows 2000 term for a partition.
• Basic Disk is a Windows 2000 term for a drive that has been
partitioned and formatted.
– Dynamic Storage is a Windows 2000 disk that has been configured
for the 2000 operating system.
• Dynamic Disk is a Windows 2000 term for volumes that can be
resized and managed without rebooting.
• Volume is a hard drive term used to describe all of a hard drive or hard
drive portions that have been combined into one unit.
Windows 2000/XP Logical Disk Management
• Dynamic disks can have different types of volumes:
– Simple Volume is disk space allocated from one hard drive.
– Spanned Volume is disk space created from multiple hard drives.
– Striped Volume is when data is written across two to thirty-two hard
drives.
– Raid 5 Volume puts data on three or more hard drives and one of the
hard drive spaces is used for parity.
– System Volume holds the files needed to boot the operating system.
– Boot Volume holds the remaining operating system files. The system
volume and the boot volume can be one and the same.
Fault Tolerance
• RAID (Redundant Array of Independent (formerly Inexpensive) Disks allows
writing to multiple hard drives for larger storage areas, better performance, and
fault tolerance.
• Fault Tolerance is the ability to continue functioning after a hardware or software
failure.
• Different RAID levels
– RAID Level 0 is also called disk striping without parity. It does not protect
data when a hard drive fails.
– RAID Level 1 is called disk mirroring or disk duplexing.
• Disk mirroring uses two or more hard drives and one disk controller.
• Disk duplexing uses two or more hard drives and two disk controllers.
– RAID Level 5 is also called disk striping with parity. It writes data to three or
more hard drives and includes parity information with the data.
High-Level Format
• The last step in preparing a hard drive for use is high-level formatting.
– High-Level Format is the process that sets up the file system for use
by the computer.
• DBR (DOS Boot Record) is area of a disk that contains system files.
• Boot Sector was previously called DBR. This section of a disk contains
information about the system files.
High-Level Format
FAT16 and NTFS Volume Structure
IDE/SCSI – Figure #32
Bootable Disks
• A technician should have a startup disk for each operating system
supported.
– ERD (Emergency Repair Disk) is a copy of the REPAIR folder
created when backing up the registry in Windows 2000 Professional
and NT Workstation. This can help when the operating system has
problems booting.
Bootable Disks
Boot Files
IDE/SCSI – Table #17
Viruses
• A Virus is a program written to cause a device not to operate in its
normal fashion.
• Common types of viruses include:
– BIOS virus
– Boot sector (MBR) virus
– File virus
– Macro virus
– Trojan Horse Programs
– Worm virus
Viruses
Virus Types
IDE/SCSI – Table #18
Logically Troubleshooting Newly Installed Drives
• Problems with new drive installations:
– Improper jumper configuration
– SCSI ID settings
– Termination
– Problems with cabling
– Drive type configuration
• A checklist for possible problems is listed on 9-64.
Logically Troubleshooting Previously Installed Drives
• Problems with hard drives that worked previously:
– Check for viruses
– Check for resource conflicts from any new hardware or software that
was installed
– Check for loose cables
– Verify bootable system files
– Verify that the hard drive is still operational
• A checklist for possible problems is listed on 9-69.
IDE Specific Errors
• Problems with IDE hard drives:
– Verify Pin 1 connection on the cable to Pin 1 connection on the drive
– Verify the master and slave jumper settings
– Verify the correct CMOS settings for the drives
– Verify if an 80 conductor cable is required.
SCSI Specific Errors
• Problems with SCSI hard drives:
– Check for incorrect termination
– Check the SCSI ID for the drives
– Check the SCSI adapter’s resources assigned
Autoexec.bat and Config.sys Errors
• To troubleshoot CONFIG.SYS and AUTOEXEC.BAT problems, step
through one command or driver at a time.
Preventive Maintenance for Hard Drives
• Preventive Maintenance will prolong the life of the computer.
– CHKDSK is a program that locates clusters disassociated from data
files.
• Lost Clusters are sectors on a disk that the file allocation table
cannot associate with any file or directory.
– SCANDISK is a software program used to detect and repair lost
clusters.
– Disk Cleanup is a Windows 2000 utility that helps free up hard drive
space by emptying the Recycle Bin, removing temporary files, etc.
Hard Drive Fragmentation
• Over time files will become fragmented on a hard drive and slow down
access time.
– Defragmentation is the process of placing files in contiguous sectors.
This allows for faster hard disk access of files.
Hard Drive Fragmentation
Fragmented Hard Drive
IDE/SCSI – Figure #34
Disk Caching/Virtual Memory
• Ways to speed up the hard drive:
– Disk Cache or Data Buffer is a portion of RAM set aside for hard
drive data that speeds up hard drive operations.
– VMM (Virtual Memory Manager) is a Windows component that
uses hard disk space as if it were RAM.
• It is best to put the swap file on a the fastest hard drive that doesn’t
contain the operating system.
• Virtual memory swap file size can be adjusted. Instructions are listed on
9-77.