IDE and SCSI Devices

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.

62
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.

64
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.