IDE%20and%20SCSI%20Devices

1
IDE and SCSI Devices

• Terms and Definitions

2
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.

3
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

4
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. Todays hard
  drives normally use a 11 interleave.

5
Hard Drive Geometry
Hard Drive Geometry
IDE/SCSI Figure 1
6
Hard Drive Geometry
Cylinder vs Tracks
IDE/SCSI Figure 2
7
Hard Drive Geometry
Sectors on Older Hard Drives
IDE/SCSI Figure 3
8
Hard Drive Geometry
Zone Bit Recording Sectors
IDE/SCSI Figure 4
9
Hard Drive Geometry
31 Interleaving
IDE/SCSI Figure 5
10
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.

11
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.

12
IDE (Integrated Drive Electronics)
PIO Modes for IDE Hard Drives
IDE/SCSI Table 1
13
IDE (Integrated Drive Electronics)
DMA Modes for IDE Hard Drives
IDE/SCSI Table 2
14
IDE (Integrated Drive Electronics)
80 and 40 Pin Conductor Cable
IDE/SCSI Figure 6
15
IDE (Integrated Drive Electronics)
IDE ATA Standards
IDE/SCSI Table 4
16
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.

17
SCSI (Small Computer System Interface)
SCSI Standards
IDE/SCSI Table 5
18
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.

19
SCSI Software Standards

• Most SCSI hard drives have software built into
  the hard drives 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)

20
Drive Configuration Overview

• The configuration of a hard drive usually
  includes setting jumpers on the drive,
  terminating properly, and performing a few
  software commands.

21
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.

22
IDE Device Configuration
IDE Motherboard Connectors
IDE/SCSI Figure 7
23
IDE Device Configuration
IDE Hard Drive Set as Master
IDE/SCSI Figure 8
24
IDE Device Configuration
Two IDE Hard Drives
IDE/SCSI Figure 9
25
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.

26
Serial ATA (SATA) Installation
Installed SATA Hard Drive and Adapter
IDE/SCSI Figure 12
27
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.

28
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.

29
SCSI ID Configuration
SCSI ID Settings (Most Significant Bit to the
Left)
IDE/SCSI Table 7
30
SCSI ID Configuration
Two Internal SCSI Devices SCSI IDs
IDE/SCSI Figure 13
31
SCSI ID Configuration
Two External SCSI Devices SCSI IDs
IDE/SCSI Figure 14
32
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

33
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.

34
SCSI Termination
SCSI Termination
IDE/SCSI Figure 15
35
SCSI Termination
Todays SCSI Terminators Pass Through
Terminator and 68-Pin Active Terminator
IDE/SCSI Figure 17
36
SCSI Termination
SCSI Symbols
IDE/SCSI Figure 19
37
SCSI Termination
Two Internal SCSI Devices - Termination
IDE/SCSI Figure 20
38
SCSI Termination
Two External SCSI Devices - Termination
IDE/SCSI Figure 21
39
SCSI Termination
Internal and External SCSI Devices - Termination
IDE/SCSI Figure 22
40
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.

41
SCSI Cables
Internal SCSI Cables
IDE/SCSI Figure 23
42
SCSI Cables
External SCSI Cables
IDE/SCSI Figure 24
43
SCSI Cables
SCSI Cables and Connectors
IDE/SCSI Table 9
44
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
  drives 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.

45
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.

46
Hard Drive Preparation Overview

• Three steps to hard drive preparation
• Low-Level Format
• Partition
• High-Level Format

47
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 computers 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.

48
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.

49
Partitioning
Clusters
IDE/SCSI Figure 25
50
Partitioning
FAT16 Partitions and Cluster Size
IDE/SCSI Table 12
51
Partitioning
FAT32 Partitions and Cluster Size
IDE/SCSI Table 13
52
Partitioning
NTFS Partitions and Cluster Size
IDE/SCSI Table 14
53
Partitioning
NT Disk Administrator
IDE/SCSI Figure 26
54
Partitioning
Hard Drive Partitioning
IDE/SCSI Figure 27
55
Partitioning
Two Logical Drives
IDE/SCSI Figure 28
56
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.

57
How Drive Letters Are Assigned
Logical Drive Letters with Two Hard Drives
IDE/SCSI Figure 30
58
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.

59
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.

60
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.

61
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.

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High-Level Format
FAT16 and NTFS Volume Structure
IDE/SCSI Figure 32
63
Bootable Disks

• A user 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.

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Bootable Disks
Boot Files
IDE/SCSI Table 17
65
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

66
Viruses
Virus Types
IDE/SCSI Table 18
67
Logically Troubleshooting Newly Installed Drives

• Problems with new drive installations
• Improper jumper configuration
• SCSI ID settings
• Termination
• Problems with cabling
• Drive type configuration

68
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

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.

70
SCSI Specific Errors

• Problems with SCSI hard drives
• Check for incorrect termination
• Check the SCSI ID for the drives
• Check the SCSI adapters resources assigned

71
Autoexec.bat and Config.sys Errors

• To troubleshoot CONFIG.SYS and AUTOEXEC.BAT
  problems, step through one command or driver at a
  time.

72
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.

73
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.

74
Hard Drive Fragmentation
Fragmented Hard Drive
IDE/SCSI Figure 34
75
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 doesnt contain the operating
  system.
• Virtual memory swap file size can be adjusted.