1. Hard Drive Technologies
Chapter 11 1

2. Overview In this chapter, you will learn how to
Explain how hard drives work
Identify and explain the PATA and SATA hard drive interfaces
Identify and explain the SCSI hard drive interfaces
Describe how to protect data with RAID
Install hard drives
Configure CMOS and install drivers
Troubleshoot hard drive installation
Instructor Tip
When gaining attention and establishing common ground, ask questions of the class such as, “Who here has ever installed a hard drive?” or “Who here has ever had a hard drive crash?”
For a positive statement, tell the class, “In this lesson, we are going to learn how to install a hard drive and diagnose hard drive problems.” 2

3. Historical/Conceptual
How Hard Drives Work 3

4. The Platter-based Hard Drive
A traditional hard disk drive (HDD) is composed of individual disks or platters.
The platters are made up of aluminum and coated with a magnetic medium.
Two tiny read/write heads service each platter.
Discussion Point
Hard Drive Housing
All moving components of the hard drive (platters, actuator arm, and read/write heads) are permanently sealed inside the housing to prevent contamination by minute particles. Even the tiniest speck of dust can destroy a hard drive and all the data it contains. Drives are assembled by the manufacturer in clean rooms.
Never open the case of a hard drive unless the drive is absolutely dead and/or totally unrecoverable, and you are just bored or curious. 4

5. The Platter-based Hard Drive (continued)
A traditional hard disk drive (HDD) is composed of individual disks, or platters, with read/write heads on actuator arms controlled by a servo motor—all contained in a sealed case that prevents contamination by outside air (see Figure 1).
Figure 1: Inside the hard drive 5

6. The Hard Drive
The closer the read/write heads are to the platter, the more densely the data can be packed on to the drive.
Hard drives use a tiny, heavily filtered aperture to equalize the air pressure between the exterior and interior of the hard drive.
Platters spin between 3,500 and 15,000 revolutions per minute (RPM).
Tech Tip
Fluid Bearings
Currently, almost all hard drives use a motor located in the center spindle supporting the drive platters. Tiny ball bearings support the spindle motor. As disk technology has advanced, these ball bearings have become the limiting factor in the three critical design criteria for hard drives: rotational speed, storage capacity, and noise levels. The higher the rotational speed of a drive, the more the metal-on-metal contact creates heat and lubricant problems that impact the lifespan of the bearings. However precisely machined, ball bearings are not perfectly round. The measurement of how much they wobble (and thus how much the drive platters wobble), called runout, is now the limiting factor on how densely you can pack information together on a disk drive. The technological fix? Fluid bearings. A fluid bearing is basically a small amount of lubricant trapped in a carefully machined housing. The use of fluid in place of metal balls means there’s no contact between metal surfaces to generate heat and wear, and no mechanical vibration, so fluid bearings can support higher rotational speeds. The runout of a fluid bearing is about one-tenth that of the best ball bearing, increasing potential information density significantly. The absence of a mechanical connection between moving parts also dramatically reduces noise levels, and the fluid itself acts to dampen the sound further. Finally, liquid bearings provide better shock resistance than ball bearings. 6

7. The Hard Drive (continued)
The aluminum platters are coated with a magnetic medium. Two tiny read/write heads service each platter, one to read the top and the other to read the bottom of the platter (see Figure 2).
Figure 2: Read/write heads on actuator arms 7

8. Data Encoding
Hard drives store data in tiny magnetic fields called fluxes
The flux switches back and forth through a process called flux reversal
Hard drives read these flux reversals at a very high speed when accessing or writing data
Fluxes in one direction are read as 0 and the other direction as 1 8

9. Data Encoding (continued)
Encoding methods used by hard drives are
Run Length Limited (RLL)
Data is stored using “runs” that are unique patterns of ones and zeroes
Can have runs of about seven fluxes
Partial Response Maximum Likelihood (PRML)
Uses a powerful, intelligent circuitry to analyze each flux reversal
Can have runs of about 16 to 20 fluxes
Significant increase in capacity (up to 1 TB) 9

10. Arm Movement in the Hard Drive
The stepper motor technology and the voice coil technology are used for moving the head actuator
Moves the arms in fixed increments or steps
Only seen in floppies today
The voice coil technology uses a permanent magnet surrounding the coil on the head actuator to move the arm
Automatically parks drive over non-data area when power removed
This is how modern HDDs work
“Parking” a drive is meaningless in today’s PCs. Book calls the head actuator the “actuator arm.” CompTIA A+ calls it the “head actuator.” The head actuator works the same in hard drives or other mass storage drives that have spinning media (FDD and optical). 10

11. Geometry
Geometry is used to determine the location of the data on the hard drive
CHS (cylinders, heads, sectors)
Used to be critical to know geometry
Had to enter into CMOS manually
Today geometry stored on hard drive
BIOS can query hard drive for geometry data
Discussion Point
The Geometry We Need to Know: Cylinders, Heads, and Sectors
Back in the old days, we always had to enter this information into the CMOS manually for the BIOS to know how to communicate with the drive. Today, this information is automatically stored on the drive and detected by the BIOS. However, since we routinely see older systems in our work, we still need to know this information. If this geometry is not marked on the drive housing, as is the case with many older drives, it is usually available at the drive manufacturer’s Web site. Suggest students write the geometry information and the jumper information on the drive housing with a marker so they won’t have to look it up again. 11

12. Heads Number of read/write heads used by the drive to store data
Two heads per platter (top and bottom)
Most hard drives have an extra head or two for their own usage, so the number may not be even
Figure 3: Two heads per platter 12

13. Cylinders
Data stored in concentric circles on the platters, called tracks
Cylinders
Group of tracks of the same diameter going completely through the drive
Figure 4: Cylinder 13

14. Sectors per Track Number of slices in the hard drive
512 bytes of storage per sector
Note that data is stored on platters.
Figure 5: Sectors per track
Data is stored on the platters in sectors 14

15. Obsolete Geometry Might see in older systems
Write precompensation cylinder
The specific cylinder from where the drive would start writing data farther apart
Internal sectors physically smaller
External sectors physically larger
This identified cylinder where spacing changed
Landing zone
Unused cylinder as “parking place” for heads
Referred to as Lzone, LZ, Park
Needed for older drives using stepper motors 15

16. Spindle or (rotational) speed
Measured in revolutions per minute (RPM)
The faster the drive, the better the performance
Common speeds:
5400, 7200, 10,000, and 15,000 RPM
Faster rotational speed produces more heat
Airflow is a key factor in reducing heat
Reduce heat with case fans or bay fans

17. Spindle or (rotational) speed (continued)
Drive bay fans sit at the front of a bay and blow air across the drive. They range in price from $10 to $100 (U.S.) and can lower the temperature of your drives dramatically. Some cases come with a bay fan built in (see Figure 6).
Figure 6: Bay fan 17

18. Figure 7: A solid-state drive (photo courtesy of Corsair)
Solid-state Drives
A solid-state drive (SSD) uses no moving parts
Fast
Expensive compared to HDDs
DRAM- and flash-based drives (latter are more common)
Solid-state technology in hard drives, memory cards, and more
Figure 7: A solid-state drive (photo courtesy of Corsair)

19. Flash-based SSDs Pure flash drives for portables Advantages:
Very low-power usage and heat generation
Very fast in reads because no moving parts
Extremely rugged—nothing to break
Disadvantages
Price (as of early 2010)
HDDs: $0.10 per GB capacity
SSDs: $3.50 per GB capacity
Capacity much lower than HDDs, but climbing
Article about how flash-based SSDs store data.

20. Parallel and Serial ATA
ATA interfaces dominate today’s market
Many changes throughout years
Parallel ATA (PATA) historically prominent
Serial ATA (SATA) since 2003
Called integrated drive electronics (IDE) 20

21. ATA Overview Cable Keywords Speed Max size ATA-1 40-pin PIO and DMA
3.3 MBps to 8.3 MBps
504 MB
ATA-2
EIDE ATAPI
11.1 MBps to 16.6 MBps
8.4 GB
ATA-3
S.M.A.R.T.
ATA-4
Ultra
16.7 MBps to 33.3 MBps
INT13
BIOS Upgrade
137 GB
ATA-5
40-pin 80-wire
ATA/33 ATA/66
44.4 MBps to 6.6 MBps
ATA-6
Big Drive
100 MBps
144 PB
ATA-7
40-pin 80-wire 7-pin
ATA/ SATA
133 MBps to 300 MBps 21

22. ATA-1 40-pin ribbon cable Allowed two drives (one master, one slave)
Programmable I/O (PIO)—traditional data transfer
3.3 MBps to 8.3 MBps
DMA—direct memory access
2.1 MBps to 8.3 MBps
Maximum capacity = 504 MB
Maximum capacity was 504 MB due to limitations of 1024 cylinders, 16 heads, 63 sectors per track, and 512 bytes per track.
Wasn’t really a true max because the 16-head bit was unworkable. Too many platters and too much complexity = too much cost. Answer was ATA-2. 22

23. Figure 9: Relation of drive, controller, and bus
Early ATA Physical Connections
Figure 8: Back of IDE drive showing 40-pin connector (left), jumpers (center), and power connector (right)
Figure 8 shows the business end of an early ATA drive, with the connectors for the ribbon cable and the power cable.
The controller is the support circuitry that acts as the intermediary between the hard drive and the external data bus. Electronically, the setup looks like Figure 9.
Figure 9: Relation of drive, controller, and bus 23

24. Figure 11: IDE interfaces on a motherboard
Early ATA Physical Connections (continued)
The ATA standard identifies the two drives as “master” and “slave.” You set one drive as master and one as slave by using tiny jumpers on the drives (see Figure 10).
The controllers are on the motherboard and manifest themselves as two 40-pin male ports, as shown in Figure 11.
Figure 10: A typical hard drive with directions (top) for setting a jumper (bottom)
Figure 11: IDE interfaces on a motherboard 24

25. ATA-2 Commonly called EIDE (Western Digital marketing term)
Increased maximum size to 8.2 GB through LBA and sector translation
Added ATAPI
Could now use CD drives
Added second controller
Added new PIO and DMA modes to increase data transfers to 16.6 MBps
Physical vs. logical geometry
Manufacturers could do much more with cylinders, but then fooled the BIOS with amazing numbers of heads.
Note: With the introduction of ATAPI, the ATA standards are often referred to as ATA/ATAPI instead of just ATA. 25

26. ATA-2 (continued) Figure 12: EIDE drive
By 1995, EIDE drives dominated the PC world. Figure 12 shows a typical EIDE drive.
If you wanted a hard drive with the maximum number of 16 heads, you would need a hard drive with eight physical platters inside the drive. Nobody wanted that many platters: it made the drives too tall, it took more power to spin up the drive, and that many parts cost too much money (see Figure 13).
Figure 12: EIDE drive 26

27. Figure 14: Multiple sectors/track
Higher Capacity with LBA
Figure 13: Too many heads
If you wanted a hard drive with the maximum number of 16 heads, you would need a hard drive with eight physical platters inside the drive. Nobody wanted that many platters: it made the drives too tall, it took more power to spin up the drive, and that many parts cost too much money (see Figure 13).
Manufacturers could make a hard drive store a lot more information if they could make hard drives with more sectors/track on the outside tracks (see Figure 14).
Figure 14: Multiple sectors/track 27

28. Figure 16: Primary and secondary controllers labeled on a motherboard
ATAPI
Figure 15: ATAPI CD-RW drive attached to a motherboard via a standard 40-pin ribbon cable
Figure 15 shows an ATAPI CD-RW drive attached to a motherboard. Figure 16 is a close-up of a typical motherboard, showing the primary controller marked as IDE1 and the secondary marked as IDE2.
Figure 16: Primary and secondary controllers labeled on a motherboard 28

29. ATA-3 Self-Monitoring Analysis and Reporting Technology
S.M.A.R.T.
No real change in other stats 29

30. S.M.A.R.T. Information Figure 17: Data Lifeguard Tools
Every hard drive maker has a free diagnostic tool (which usually works only for their drives) that will do a S.M.A.R.T. check along with other tests. Figure 17 shows Western Digital’s Data Lifeguard Tools in action. Note that it says only whether the drive has passed or not. Figure 18 shows some S.M.A.R.T. information.
Figure 18: S.M.A.R.T. information 30

31. ATA-4 Introduced Ultra DMA Modes Ultra DMA Mode 2 also called ATA/33
Ultra DMA Mode 0: 16.7 MBps
Ultra DMA Mode 1: 25 MBps
Ultra DMA Mode 2: 33 MBps
These are forms of DMA bus mastering
Ultra DMA Mode 2 also called ATA/33 31

32. INT13 Extensions
ATA-1 standard actually written for hard drives up to 137 GB
BIOS limited it to 504 MB due to cylinder, head, and sector maximums
ATA-2 implemented LBA to fool the BIOS, enabling drives up to 8.4 GB
INT13 Extensions extended BIOS commands
Enabled drives up to 137 GB 32

33. ATA-5 Introduced newer Ultra DMA Modes
Ultra DMA Mode 3: 44.4 MBps
Ultra DMA Mode 4: 66.6 MBps
Ultra DMA Mode 4 also called ATA/66
Used 40-pin cable, but had 80 wires
Blue connector—to controller
Gray connector—slave drive
Black connector—master drive
Figure 19: ATA/66 cable 33

34. ATA-6 “Big Drives” introduced (name soon changed to ATA/ATAPI-6)
Replaced INT13 & 24-bit LBA to 48-bit LBA
Increased maximum size to 144 PB
144,000,000 GB
Introduced Ultra DMA 5
Ultra DMA Mode 5: 100 MBps (ATA/100)
Used same 40-pin, 80-wire cables as ATA-5 34

35. ATA-7 Introduced Ultra DMA 6 Introduced Serial ATA (SATA)
Ultra DMA Mode 6: 133 MBps (ATA/133)
Used same 40-pin, 80-wire cables as ATA-5
Didn’t really take off due to SATA’s popularity
Introduced Serial ATA (SATA)
Increased throughput to 150 MBps to 300 MBps 35

36. End of PATA Ultra DMA Mode 6 Problems with PATA Up to 133 Mbps ATA/133
80-wire cable
Problems with PATA
Wide, flat cables impede airflow
Cable limited to 18”
No hot-swapping
Reached limits of technology

37. power (left) and data (right) cables
Serial ATA
Serial ATA (SATA) creates a point-to-point connection between the device and the controller or host bus adapter (HBA)
Narrower cables result in better airflow and cable control in the PC
Maximum cable length of 1 meter
Hot-swappable
No drive limit
Throughput of 150 MBps to 600 MBps
Point-to-point means that there are no intermediary chips or devices to slow down the flow of data. The drive and controller follow the same set of rules and it’s only one drive, one controller.
SATA specifications and speeds are: 1.0: 1.5 GBPS; 2.0: 3 GBPS; and 3.0: 6 GBPS.
Figure 20: SATA hard disk
power (left) and data (right) cables 37

38. SATA Bridge Figure 21: SATA bridge
SATA is backward compatible with current PATA standards and enables you to install a parallel ATA device, including a hard drive, optical drive, and other devices, to a serial ATA controller by using a SATA bridge. A SATA bridge manifests as a tiny card that you plug directly into the 40-pin connector on a PATA drive. As you can see in Figure 21, the controller chip on the bridge requires separate power; you plug a Molex connector into the PATA drive as normal. When you boot the system, the PATA drive shows up to the system as a SATA drive.
Figure 21: SATA bridge 38

39. AHCI Windows Vista/7 support Advanced Host Controller Interface (AHCI)
Efficient way to work with SATA HBAs
Makes hot-swapping work well (otherwise have to run the Add New Hardware Wizard)
Native command queuing (NCQ) is a disk- optimization feature that enables faster read/write speeds
Implement AHCI in CMOS before installing the OS
NCQ is a technology that enables the hard drive to organize read and write requests to optimize them. This is especially useful on server drives that get multiple simultaneous read/write requests.
You must implement AHCI in CMOS before you install Vista/7 (otherwise you must edit the registry).

40. SATA Naming SATA drives come in two flavors
SATA 1.5Gb
SATA 3Gb
Marketing hype has branded SATA 3Gb drives as SATA II
SATA committee is called the SATA-IO
Note the numbers don’t quite add up
1.5 Gb = 192 MBps, not 150 MBps
Up to 20 percent lost to overhead and encoding scheme, thus the lower actual speed
The SATA 6Gb/s drives started appearing in late The platter-based drives don’t see any benefit by going SATA 6Gb/s, but the SSDs can. Exceedingly rare as of January 2010.

41. eSATA External Serial ATA External SATA
Extends SATA bus to external devices
Cable length up to 2 meters
eSATA extends the SATA bus at full speed, which tops out at a theoretical 6 Gbps, whereas the fastest USB connection (USB 3.0, also called SuperSpeed USB) maxes out at 5 Gbps. 41

42. External Serial ATA (continued)
Figure 23: eSATA ExpressCard
External SATA (eSATA) extends the SATA bus to external devices, as the name would imply. The eSATA drives use connectors similar to internal SATA, but they’re keyed differently so you can’t mistake one for the other. Figure 22 shows eSATA connectors on the back of a motherboard. You can similarly upgrade laptop systems to support external SATA devices by inserting an eSATA ExpressCard (see Figure 23).
Figure 22: eSATA connectors 42

43. SCSI Small Computer System Interface43

44. SCSI Pronounced “Scuzzy” Been around since 1970s
Devices can be internal or external
Historically the choice for RAID
Faster than PATA
Could have more than four drives
SATA replacing SCSI in many applications 44

45. SCSI Chains
A SCSI chain is a series of SCSI devices working together through a host adapter.
The host adapter is a device that attaches the SCSI chain to the PC.
All SCSI devices are divided into internal and external groups. 45

46. Figure 24: SCSI host adapter
SCSI Chains (continued)
SCSI manifests itself through a SCSI chain, a series of SCSI devices working together through a host adapter. The host adapter provides the interface between the SCSI chain and the PC. Figure 24 shows a typical SCSI PCI host adapter. Many techs refer to the host adapter as the SCSI controller, so you should be comfortable with both terms.
Figure 24: SCSI host adapter 46

47. SCSI Chains (continued)
Figure 26: Back of external SCSI device
Figure 25: Internal SCSI CD-ROM
All SCSI devices can be divided into two groups: internal and external. Internal SCSI devices are attached inside the PC and connect to the host adapter through the latter’s internal connector. Figure 25 shows an internal SCSI device, in this case a CD-ROM drive. External devices hook to the external connector of the host adapter. Figure 26 is an example of an external SCSI device. 47

48. Internal Devices
Internal SCSI devices are installed inside the PC and connect to the host adapter through the internal connector.
Internal devices use a 68-pin ribbon cable.
Cables can be connected to multiple devices. 48

49. Internal Devices (continued)
Figure 28: 50-pin HD port on SCSI host adapter
Figure 27: Typical 68-pin ribbon cable
Internal SCSI devices connect to the host adapter with a 68-pin ribbon cable (see Figure 27). This flat, flexible cable functions precisely like a PATA cable. Many external devices connect to the host adapter with a 50-pin high-density (HD) connector. Figure 28 shows a host adapter external port. Higher-end SCSI devices use a 68-pin HD connector. 49

50. External Devices
External SCSI devices are connected to external connection of host adapter.
External devices may have two connections in the back to allow for daisy-chaining.
A standard SCSI chain can connect 15 devices, plus the host adapter.
External devices connect with a 50-pin high-density connector. Some use a 68-pin high-density connector. Some early versions of SCSI used a 25-pin connector, which was typically used on some older Apple devices and ZIP drives. 50

51. External Devices (continued)
Figure 30: Internal and external devices on one SCSI chain
Figure 29: Internal SCSI chain with two devices
Multiple internal devices can be connected simply by using a cable with enough connectors (see Figure 29). The 68-pin ribbon cable shown in Figure 27, for example, can support up to four SCSI devices, including the host adapter.
The process of connecting a device directly to another device is called daisy- chaining. You can daisy-chain as many as 15 devices to one host adapter. SCSI chains can be internal, external, or both (see Figure 30). 51

52. Figure 31: IDs don’t conflict between separate SCSI chains.
SCSI IDs
Each SCSI device must have a unique SCSI ID.
The values of ID numbers range from 0 to 15.
No two devices connected to a single host adapter can share the same ID number.
No order for the use of SCSI IDs, and any SCSI device can have any SCSI ID.
Figure 31: IDs don’t conflict between separate SCSI chains.
Make sure you can look at any SCSI device and understand how to set its SCSI ID! 52

53. SCSI IDs (continued)
The SCSI ID for a particular device can be set by configuring jumpers, switches, or even dials.
Use your binary knowledge to set the device ID:
Device 1 = Off, Off, Off, On
Device 7 = Off, On, On, On
Device 15 = On, On, On, On
Host adapters often set to 7 or 15 but can be changed. 53

54. Figure 32: Location of the terminated devices
Termination
Terminators are used to prevent a signal reflection that can corrupt the signal.
Pull-down resistors are usually used as terminators.
Only the ends of the SCSI chains should be terminated.
Most manufacturers build SCSI devices that self-terminate.
Discussion Point
Termination
All electronic signals can reflect back (or echo) along the wire. On some systems, such as SCSI and coaxial networks, this can cause chaos, as devices do not know what signal to listen to. A terminator is basically a resistor that absorbs the signal to prevent it from reflecting back. All SCSI chains, without exception, have to be terminated at both ends of the chain, but never in the middle.
Figure 32: Location of the terminated devices 54

55. Termination (continued)
Figure 33: Setting termination
The rule with SCSI is that you must terminate only the ends of the SCSI chain. You have to terminate the ends of the cable, which usually means that you need to terminate the two devices at the ends of the cable. Do not terminate devices that are not on the ends of the cable. Figure 32 shows some examples of where to terminate SCSI devices.
Because any SCSI device might be on the end of a chain, most manufacturers build SCSI devices that can self-terminate. Some devices can detect that they are on the end of the SCSI chain and automatically terminate themselves. Most devices, however, require you to set a jumper or switch to enable termination (see Figure 33).
Figure 32: Location of the terminated devices 55

56. Protecting Data with RAID56

57. Protecting Data The most important part of a PC is the data it holds.
Companies have gone out of business because of losing data on hard drives.
Hard drives will eventually develop faults.
Fault tolerance enables systems to operate even when a component fails.
Redundant array of inexpensive disks (RAID) is one such technology. 57

58. Protecting Data (continued)
Figure 35: Duplexing drives
Figure 34:Mirrored drives
Disk mirroring means that you install a hard drive controller that reads and writes data to two hard drives simultaneously (see Figure 34). The data on each drive would always be identical. One drive would be the primary drive and the other drive, called the mirror drive, would not be used unless the primary drive failed.
You can also use a separate controller for each drive. With two drives, each on a separate controller, the system will continue to operate even if the primary drive’s controller stops working. This super-drive mirroring technique is called disk duplexing (see Figure 35).
Disk striping by itself provides no redundancy. If you save a small Microsoft Word file, for example, the file is split into multiple pieces; half of the pieces go on one drive and half on the other (see Figure 36).
Figure 36: Disk striping 58

59. RAID Level 0 Disk striping Not fault tolerant
Writes data across multiple drives at once
Requires at least two hard drives
Provides increased read and writes
Not fault tolerant
If any drive fails, the data is lost 59

60. RAID Level 1
Disk mirroring/duplexing is the process of writing the same data to two drives at the same time
Requires two drives
Produces an exact mirror of the primary drive
Mirroring uses the same controller
Duplexing uses separate controllers 60

61. RAID Levels 2 to 4 RAID 2 RAID 3 and 4
Disk striping with multiple parity drives
Not used
RAID 3 and 4
Disk striping with dedicated parity
Dedicated data drives and dedicated parity drives
Quickly replaced by RAID 5 61

62. RAID Level 5 Disk striping with distributed parity
Distributes data and parity evenly across the drives
Requires at least three drives
Most common RAID implementation 62

63. RAID Level 6 Super disk striping with distributed parity
RAID 5 with asynchronous and cached data capability
Requires at least five drives, but can lose up to two drives and still recover
The CompTIA A+ Certification exams are interested only in your understanding RAID levels 0, 1, and 5. I’m unaware of anyone actually using RAID levels 2, 3, or 4 in modern systems. Just be aware that these other levels of RAID exist.
****Also RAID 0+1 and 1+0 (10)**** 63

64. RAID Oddities and JBOD
Consumer-oriented boards offer “special” features
RAID 0+1
Two striped sets mirrored
RAID 1+0 (RAID “10”)
Two mirrored sets striped
Both require four drives
Just a Bunch of Disks (JBOD)

65. Implementing RAID SCSI has been the primary choice in the past
Faster than PATA
Hot-swappable
PATA supported only four drives
SATA today viewed as comparable choice
Speeds comparable to SCSI
Less expensive than SCSI
Dedicated SATA controllers can support up to 15 drives 65

66. Hardware vs. Software Hardware RAID Software RAID Dedicated controller
Operating system views it as single volume
Software RAID
Operating system recognizes all individual disks
Combines them together as single volume 66

67. Figure 37: Disk Management tool of Computer Management
Hardware vs. Software (continued)
The most common software implementation of RAID is the built-in RAID software that comes with Windows 2008 Server and Windows Server R2. The Disk Management program in these Windows Server versions can configure drives for RAID 0, 1, or 5, and it works with PATA, SATA, and/or SCSI (see Figure 37). Disk Management in Windows XP and Windows Vista can only do RAID 0, while Windows 7’s Disk Management can do RAID 0 and 1.
Figure 37: Disk Management tool of Computer Management
in Windows 2003 Server 2008 R2 67

68. Hardware vs. Software (continued)
Figure 39: RAID configuration utility
Figure 38: Serial ATA RAID controller
Hardware RAID centers on an intelligent controller—either a SCSI host adapter or a PATA/SATA controller that handles all of the RAID functions (see Figure 38).
Hardware-based RAID is invisible to the operating system and is configured in several ways, depending on the specific chips involved. Most RAID systems have a special configuration utility in Flash ROM that you access after CMOS but before the OS loads. Figure 39 shows a typical firmware program used to configure a hardware RAID solution. 68

69. Personal RAID ATA RAID controller chips have gone down in price.
Many motherboards are now shipping with RAID built-in.
The future is RAID.
RAID has been around for 20 years, but is now less expensive and moving into desktop systems. 69

70. Installing Drives 70

71. Connecting Your Drive Choosing your drive Jumpers and cabling on PATA
PATA, SATA, or SCSI
Check BIOS and motherboard for support
Jumpers and cabling on PATA
Master
Slave
Cable select 71

72. Connecting Your Drive (continued)
Figure 40: Settings for RAID in CMOS
Many motherboards with built-in RAID controllers have a CMOS setting that enables you to turn the RAID on or off (see Figure 40).
If you have only one hard drive, set the drive’s jumpers to master or standalone. If you have two drives, set one to master and the other to slave. See Figure 41 for a close-up of a PATA hard drive, showing the jumpers.
Figure 41: Master/slave jumpers on a hard drive 72

73. Figure 42: Drive label showing master/slave settings
Connecting Your Drive (continued)
Figure 42 shows the label of one of these drives, so you can see how to set the drive to master or slave.
Figure 42: Drive label showing master/slave settings 73

74. Connecting ATA Drives PATA SATA SATA best practice
Ribbon cable pin 1 to pin 1
Molex for power
SATA
Cable keyed, so goes in one way
SATA for power, though some can use Molex
SATA best practice
Install drive you want as primary/bootable into first SATA controller, usually SATA 0

75. Figure 43: Properly connected SATA cable
Connecting ATA Drives (continued)
Installing SATA hard disk drives is even easier than installing PATA devices because there’s no master, slave, or cable select configuration to mess with. In fact, there are no jumper settings to worry about at all, as SATA supports only a single device per controller channel. Simply connect the power and plug in the controller cable as shown in Figure 43—the OS automatically detects the drive and it’s ready to go.
Figure 43: Properly connected SATA cable 75

76. Connecting SSDs Most likely to find in portable PCs
Connect the same way HDDs connect
PATA
SATA
Drivers needed for pre-Vista Windows

77. Connecting SCSI Drives
First need compatible controller
Different types of SCSI
Connect data cable
Reversing this cable can damage drive, data, or both
Pin 1 to pin 1, just like PATA
Connect power—Molex connector
Configure SCSI IDs on drives and controller 77

78. BIOS Support: Configuring CMOS and Installing Drivers78

79. Configuring Controllers and Autodetection
Enable controller
Auto detection runs
Enable AHCI
Figure 45: Old standard CMOS settings
Figure 44: Typical controller settings in CMOS 79

80. Figure 46: New standard CMOS features
Configuring Controllers and Autodetection (continued)
One common numbering method uses the term channels for each controller. The first boot device is channel 1, the second is channel 2, and so on. (PATA channels may have a master and a slave, but a SATA channel has only a master, because SATA controllers support only one drive.) So instead of names of drives, you see numbers. Take a look at Figure 46.
Figure 46: New standard CMOS features 80

81. Boot Order
Identifies where computer will try to load an operating system
Multiple devices configured
First one with an OS will boot
Figure 47: Boot order 81

82. Troubleshooting Hard Drive Installation
Autodetect fails
Power
Ribbon cable installed improperly
Jumpers set incorrectly
Simplify and try again, one drive at a time
Physical settings correct? Try CMOS errors
Controller disabled
ATA level supported? (i.e., is the drive too large for your BIOS to see properly?)
Check the manufacturer's Web site for known issues

83. Beyond A+ Hybrid Hard Drives (HHD)
Combine flash memory and traditional platters
Up to 256-MB flash for fast cache for data and boot
Essential OS boot files on flash
Platters do not spin by default
Lower power usage
Read/write to flash unless need data from HDD or buffer exceeded
Could shave boot times in half and add battery life
Only Windows Vista and Windows 7