Ch07

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Ch07

  1. 1. A+ Guide to Hardware, 4e Chapter 7 Hard Drives
  2. 2. Objectives• Learn how the organization of data on floppy drives and hard drives is similar• Learn about hard drive technologies• Learn how a computer communicates with a hard drive• Learn how to install a hard drive• Learn how to solve hard drive problemsA+ Guide to Hardware, 4e 2
  3. 3. Introduction• Hard drive: most important secondary storage device• Hard drive technologies have evolved rapidly – Hard drive capacities and speeds have increased – Interfaces with the computer have also changed• Floppy disk will be presented before hard drives – Floppy disk is logically organized like a hard drive• Practical applications: – Managing problems occurring during drive installation – Troubleshooting hard drives after installationA+ Guide to Hardware, 4e 3
  4. 4. Learning from Floppy Drives• Floppy drives are an obsolescent technology – Replacements: CD drives and USB flash memory• Good reasons for studying floppy drive technology – Developing support skills for legacy applications – Building a foundation for hard drive support skill setA+ Guide to Hardware, 4e 4
  5. 5. How Floppy Drives Work• Main memory is organized logically and physically• Secondary storage devices are similarly organized – Physical storage: how data is written to media – Logical storage: how OS and BIOS view stored data• How data is physically stored on a floppy disk – Two types of floppy disk: 5 ¼ inch or 3 ½ inch – Subsystem: drive, 34-pin cable, connector, power cord – Formatting: marking tracks and sectors on a disk – Magnetic read/write heads read/write binary 1s and 0s – Heads attach to actuator arm that moves over surface A+ Guide to Hardware, 4e 5
  6. 6. Figure 7-4 3 1 -inch, high-density floppy disk showing tracks and sectorsA+ Guide to Hardware, 4e 6
  7. 7. Figure 7-5 Inside a floppy disk driveA+ Guide to Hardware, 4e 7
  8. 8. How Floppy Drives Work (continued)• How data is logically stored on a floppy disk – Floppy drives are always formatted using FAT12 – Cluster (file allocation unit): smallest grouping of sectors – The BIOS manages the disk as a set of physical sectors – OS treats the disk as list of clusters (file allocation table) – A 3 ½ inch high density floppy disk has 2880 clusters • A cluster contains one sector, which contains 512 bytes• Format floppy disk using Format or Windows Explorer – Structures and features added to the disk • Tracks, sectors, boot record, two FATs, root directory A+ Guide to Hardware, 4e 8
  9. 9. Figure 7-6 Clusters, or file allocation units, are managed by the OS in the file allocation table, but BIOS manages these clusters as one or two physical sectors on the diskA+ Guide to Hardware, 4e 9
  10. 10. How to Install a Floppy Drive• It is more cost-effective to replace than repair a drive• A simple seven-step installation procedure: – 1. Turn off computer, unplug power cord, remove cover – 2. Unplug the power cable to the old floppy drive – 3. Unscrew and dismount the drive – 4. Slide the new drive into the bay – 5. If drive is new, connect data cable to motherboard – 6. Connect data cable and power cord to drive – 7. Replace the cover, turn on computer, verify status A+ Guide to Hardware, 4e 10
  11. 11. Figure 7-8 Connect colored edge of cable to pin 1A+ Guide to Hardware, 4e 11
  12. 12. How Hard Drives Work• Components of a hard drive: – One, two, or more platters (disks) – Spindle to rotate all disks – Magnetic coating on disk to store bits of data – Read/write head at the top and bottom of each disk – Actuator to move read/write head over disk surface – Hard drive controller: chip directing read/write head• Head (surface) of platter is not the read/write head• Physical organization includes a cylinder – All tracks that are the same distance from disk centerA+ Guide to Hardware, 4e 12
  13. 13. Figure 7-10 Inside a hard drive caseA+ Guide to Hardware, 4e 13
  14. 14. Figure 7-11 A hard drive with two plattersA+ Guide to Hardware, 4e 14
  15. 15. Tracks and Sectors on the Drive• Tracks on older drives held the same amount of data• Newer drives use zone bit recording – Tracks near center have smallest number sectors/track – Number of sectors increase as tracks grow larger – Every sector still has 512 bytes – Sectors identified with logical block addressing (LBA)A+ Guide to Hardware, 4e 15
  16. 16. Figure 7-13 Floppy drives and older hard drives use a constant number of sectors per trackA+ Guide to Hardware, 4e 16
  17. 17. Figure 7-14 Zone bit recording can have more sectors per track as the tracks get largerA+ Guide to Hardware, 4e 17
  18. 18. Low-Level Formatting• Two formatting levels: – Low-level: mark tracks and sectors – High-level: create boot sector, file system, root directory• Manufacturer currently perform most low-level formats – Using the wrong format program could destroy drive – If necessary, contact manufacturer for format program• Problem: track and sector markings fade – Solution for older drives: perform low-level format – Solution for new drive: backup data and replace drive• A+ Guide tozero-fill4eutilities do not do low-level formats Note: Hardware, 18
  19. 19. Calculating Drive Capacity on Older Drives• Constant number of sectors per track• The formula was straightforward: – Cylinders x heads x sectors/track x 512 bytes/sector• Example: 855 cylinders, 7 heads, 17 sectors/track – 855 x 7 x 17 x 512 bytes/sector = 52,093,440 bytes – Divide by 1024 twice to convert to 49.68 MB capacity A+ Guide to Hardware, 4e 19
  20. 20. Drive Capacity for Today’s Drives• The OS reports the capacity of hard drives• Accessing capacity data using Windows Explorer – Right-click the drive letter – Select Properties on the shortcut menu• Calculating total capacity if drive is fully formatted – Record capacity of each logical drive on hard drive – Add individual capacities to calculate total capacity• Reporting total capacity (regardless of formatting) – Windows 2000/XP: use Disk Management – Windows 9x: use FdiskA+ Guide to Hardware, 4e 20
  21. 21. Hard Drive Interface Standards• Facilitate communication with the computer system• Several standards exist: – Several ATA standards – SCSI – USB – FireWire (also called 1394) – Fibre Channel• The various standards will be coveredA+ Guide to Hardware, 4e 21
  22. 22. The ATA Interface Standards• Specify how drives communicate with PC system – Drive controller interaction with BIOS, chipset, OS – Type of connectors used by the drive – The motherboard or expansion cards• Developed by Technical Committee T13• Published by ANSI• Selection criteria: – Fastest standard that the motherboard supports – OS, BIOS, and drive firmware must support standardA+ Guide to Hardware, 4e 22
  23. 23. Table 7-1 Summary of ATA interface standards for storage devicesA+ Guide to Hardware, 4e 23
  24. 24. The ATA Interface Standards (continued)• Parallel ATA – Allows two connectors for two 40-pin data cables – Ribbon cables can accommodate one or two drives• EIDE (Enhanced Integrated Device Electronics) – Pertains to how secondary storage device works – Drive follows AT Attachment Packet Interface (ATAPI) – Four parallel ATA devices can attach with two cables• Serial ATA (SATA) cabling – Use a serial data path rather than a parallel data path – Types of SATA cabling: internal and externalA+ Guide to Hardware, 4e 24
  25. 25. Figure 7-16 A PC’s hard drive subsystem using parallel ATAA+ Guide to Hardware, 4e 25
  26. 26. Figure 7-18 A hard drive subsystem using the new serial ATA data cableA+ Guide to Hardware, 4e 26
  27. 27. The ATA Interface Standards (continued)• DMA (direct memory access) transfer mode – 7 modes (0 - 6) bypassing CPU in transfer of data• PIO (Programmed Input/Output) transfer mode – 5 modes (0 - 4) involving CPU in data transfer• Independent device timing – Enables two drives to run at different speed• ATA/ATAPI-6 (ATA/100) breaks the 137 GB barrier – Addressable space is 144 petabytes (1.44 x 1017 PB) – Must have support of board, BIOS, OS, IDE controllerA+ Guide to Hardware, 4e 27
  28. 28. Figure 7-21 The 137-GB barrier existed because of the size of the numbers used to address a sectorA+ Guide to Hardware, 4e 28
  29. 29. The ATA Interface Standards (continued)• Configuring parallel ATA drives – Each of two IDE connectors supports an IDE channel – Primary/secondary channels each support two devices – EIDE devices: hard drive, DVD, CD and Zip drives – Devices in each channel configured as master/slave – Designate master/slave: jumpers, DIP switches, cable• Configuring serial ATA drives – One ATA cable supports one drive (no master/slave)• Use an ATA controller card in two circumstances: – IDE connector not functioning or standard not supported A+ Guide to Hardware, 4e 29
  30. 30. Figure 7-22 A motherboard has two IDE channels; each can support a master and slave drive using a single EIDE cableA+ Guide to Hardware, 4e 30
  31. 31. Figure 7-25 Rear of a serial ATA drive and a parallel ATA driveA+ Guide to Hardware, 4e 31
  32. 32. SCSI Technology• Small Computer System Interface standards – For system bus to peripheral device communication – Support either 7 or 15 devices (depends on standard) – Provide for better performance than ATA standards• The SCSI subsystem – SCSI controller types: embedded or host adapter – Host adapter supports internal and external devices – Daisy chain: combination of host adapter and devices – Each device on bus assigned SCSI ID (0 - 15) – A physical device can embed multiple logical devicesA+ Guide to Hardware, 4e 32
  33. 33. Figure 7-28 Using a SCSI bus, a SCSI host adapter can support internal and external SCSI devicesA+ Guide to Hardware, 4e 33
  34. 34. SCSI Technology (continued)• Terminating resistor – Plugged into last device at the end of the chain – Reduces electrical noise or interference on the cable• Various SCSI standards – SCSI are SCSI-1, SCSI-2, and SCSI-3 • Also known as regular SCSI, Fast SCSI, Ultra SCSI – Serial attached SCSI (SAS): compatible with serial ATA – Ensure all components of subsystem use one standard A+ Guide to Hardware, 4e 34
  35. 35. Other Interface Standards• USB (Universal Serial Bus) – USB 1.1 and USB 2.0 accommodate hard drives – A USB device connects to a PC via a USB port• IEEE 1394 (FireWire) – Uses serial transmission of data – Device can connect to PC via FireWire external port – Device also attaches to an internal connector• Fibre Channel – Rival to SCSI – Allows up to 126 devices on a single busA+ Guide to Hardware, 4e 35
  36. 36. Figure 7-31 This CrossFire hard drive holds 160GB and uses a 1394a or USB 2.0 connectionA+ Guide to Hardware, 4e 36
  37. 37. How to Select a Hard Drive• Hard drive must match OS and motherboard• BIOS uses autodetection to prepare the device – Drive capacity and configuration are selected – Best possible ATA standard is part of configuration• Selected device may not supported by BIOS• Troubleshooting tasks (if device is not recognized) – Flash the BIOS – Replace the controller card – Replace the motherboardA+ Guide to Hardware, 4e 37
  38. 38. Installations Using Legacy BIOS• Older hard drive standards that may be encountered – CHS (cylinder, head, track) mode for drives < 528 MB – Large (ECHS) mode for drives from 504 MB - 8.4 GB – The 33.8 GB limitation or the 137 GB limitation• How to install a drive not supported by BIOS – Let the BIOS see the drive as a smaller drive – Upgrade the BIOS – Replace the motherboard – Use a software interface between BIOS and drive – Substitute BIOS with ATA connector and firmwareA+ Guide to Hardware, 4e 38
  39. 39. Steps to Install a Parallel ATA Drive• Components needed: – The drive itself – 80-conductor or 40-conductor data cable – Kit to make drive fit into much larger bay (optional) – Adapter card (if board does not have IDE connection)• Steps for installing parallel ATA drive: – Step 1: Prepare for the installation • Know your starting point • Read the documentation • Plan the drive configuration • Prepare your work area and take precautionsA+ Guide to Hardware, 4e 39
  40. 40. Figure 7-32 Plan for the location of drives within baysA+ Guide to Hardware, 4e 40
  41. 41. Steps to Install a Parallel ATA Drive (continued)• Steps for installing parallel ATA drive (continued): – Step 2: Set the jumpers or DIP switches – Step 3: Mount the drive in the drive bay • Remove the bay for the hard drive • Securely mount the drive in the bay • Connect the data cables to the drives (can be done later) • Re-insert (and secure) the bay in the case • Install a power connection to each drive • Connect the data cable to the IDE connector on board • Attach bay cover and other connections (if needed) • Verify BIOS recognizes device before adding coverA+ Guide to Hardware, 4e 41
  42. 42. Figure 7-33 A parallel ATA drive most likely will have diagrams of jumper settings for master and slave options printed on the drive housingA+ Guide to Hardware, 4e 42
  43. 43. Figure 7-41 Connect a power cord to each driveA+ Guide to Hardware, 4e 43
  44. 44. Steps to Install a Parallel ATA Drive (continued)• Steps for installing parallel ATA drive (continued): – Step 4: Use CMOS setup to verify hard drive settings – Step 5: Partition and format the drive • If installing an OS, boot from Windows setup CD • If not, use Disk Management utility or Fdisk and FormatA+ Guide to Hardware, 4e 44
  45. 45. Figure 7-45 Standard CMOS setupA+ Guide to Hardware, 4e 45
  46. 46. Serial ATA Hard Drive Installations• No jumpers to set on the drive• Each serial ATA connector is dedicated to 1 drive• A simpler installation process: – Install the drive in the bay (like parallel ATA drive) – Connect a power cord to the drive• Documentation identifies which connector to use – Example: use red connectors (SATA1, SATA2) first• After checking connections, verify drive is recognizedA+ Guide to Hardware, 4e 46
  47. 47. Figure 7-48 This motherboard has four serial ATA connectorsA+ Guide to Hardware, 4e 47
  48. 48. Figure 7-49 American Megatrends, Inc. CMOS setup screen shows installed drivesA+ Guide to Hardware, 4e 48
  49. 49. Installing a Hard Drive in a Wide Bay• Universal bay kit: adapts a drive to a wide bay• Adapter spans distance between drive and bayA+ Guide to Hardware, 4e 49
  50. 50. Figure 7-52 Hard drive installed in a wide bay using a universal bay kit adapterA+ Guide to Hardware, 4e 50
  51. 51. Troubleshooting Hard Drives• Problems occur before and after installation• Problems may be hardware or software related• Hardware-related problems will be addressedA+ Guide to Hardware, 4e 51
  52. 52. Problems with Hard Drive Installations• CMOS setup does not reflect new hard drive – Solution: Enable autodetection and reboot system• Error message: “ Hard drive not found.” – Reseat the data cable and reboot the PC• Error message: “No boot device available.” – Insert bootable disk and restart the machine• Error message 601 appears on the screen – Connect the power cord to the floppy disk drive• Error message: “Hard drive not present” – Restore jumpers to their original stateA+ Guide to Hardware, 4e 52
  53. 53. Problems with Hard Drive Installations (continued)• Things to check if CMOS setup does not show drive – Does your system BIOS recognize large drives? – Is autodetection correctly configured in CMOS setup? – Are the jumpers on the drive set correctly? – Are the power cord and data cable connected?A+ Guide to Hardware, 4e 53
  54. 54. How to Approach a Hard Drive Problem After the Installation• Some post-installation problems – Corrupted data files – A corrupted Windows installation – A hardware issue preventing system from booting• Preparation steps – Start with the end user: conduct an interview – Prioritize what you have learned • Example: make data backup your first priority – Be aware of available resources • Examples: documentation, Internet, Technical SupportA+ Guide to Hardware, 4e 54
  55. 55. Hard Drive Hardware Problems• Causes of problems present during boot: – Hard drive subsystem – Partition table – File system on the drive – Files required for the OS to boot• Some things to do if POST reveals problem – Check the jumper settings on the drive – Check the cable for frayed edges or other damage – Try booting from another media; e.g. setup CD – Check manufacturer Web site for diagnostic softwareA+ Guide to Hardware, 4e 55
  56. 56. Hard Drive Hardware Problems (continued)• Bumps are bad – A scratched surface may cause a hard drive crash – Data may be recovered, even if drive is inaccessible• Invalid drive or drive specification – System BIOS cannot read partition table information – Boot from recovery CD and check partition table – To be covered in later chapters• Bad sector errors – Problem due to fading tracks and sectors – Solution: replace the driveA+ Guide to Hardware, 4e 56
  57. 57. Troubleshooting Floppy Drives and Disks• Table 7-4 has two columns – One identifies errors occurring before and after boot – Another displays troubleshooting tasksA+ Guide to Hardware, 4e 57
  58. 58. Table 7-4 Floppy drive and floppy disk errors that can occur during and after the bootA+ Guide to Hardware, 4e 58
  59. 59. Table 7-4 Floppy drive and floppy disk errors that can occur during and after the boot (continued)A+ Guide to Hardware, 4e 59
  60. 60. Summary• Current floppy disks are 3 ½ inch, high-density disks• Floppy disk format: 80 tracks, each with 8 sectors• Hard drive physical organization: cylinders, tracks, sectors• Hard drive logical organization: boot record, file allocation tables, and root directory• Secondary storage device communicates with system using a standard, such as ATA or SCSI A+ Guide to Hardware, 4e 60
  61. 61. Summary (continued)• Parallel ATA (or EIDE): allows connection of up to 4 devices• Serial ATA (SATA): specifies one cable per device• SCSI group: allow up to 7 or 15 physical devices and multiple logical devices per physical device• Other drive interface standards: USB, FireWire, Fibre Channel• Newly installed hard drives are usually automatically detected by BIOS A+ Guide to Hardware, 4e 61

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