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. Today’s hard drives normally use a 1:1 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
3:1 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 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)

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 Today’s 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 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.

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 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.

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 adapter’s 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 doesn’t contain the operating system.
Virtual memory swap file size can be adjusted.