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A+ Guide to Hardware, 4e

A+ Guide to Hardware, 4e. Chapter 7 Hard Drives. 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

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A+ Guide to Hardware, 4e

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  1. A+ Guide to Hardware, 4e Chapter 7 Hard Drives

  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 problems A+ Guide to Hardware, 4e

  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 installation A+ Guide to Hardware, 4e

  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 set A+ Guide to Hardware, 4e

  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

  6. Figure 7-4 3 1 -inch, high-density floppy disk showing tracks and sectors A+ Guide to Hardware, 4e

  7. Figure 7-5 Inside a floppy disk drive A+ Guide to Hardware, 4e

  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 Formator Windows Explorer • Structures and features added to the disk • Tracks, sectors, boot record, two FATs, root directory A+ Guide to Hardware, 4e

  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 disk A+ Guide to Hardware, 4e

  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

  11. Figure 7-8 Connect colored edge of cable to pin 1 A+ Guide to Hardware, 4e

  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 center A+ Guide to Hardware, 4e

  13. Figure 7-10 Inside a hard drive case A+ Guide to Hardware, 4e

  14. Figure 7-11 A hard drive with two platters A+ Guide to Hardware, 4e

  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

  16. Figure 7-13 Floppy drives and older hard drives use a constant number of sectors per track A+ Guide to Hardware, 4e

  17. Figure 7-14 Zone bit recording can have more sectors per track as the tracks get larger A+ Guide to Hardware, 4e

  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 • Note: zero-fill utilities do not do low-level formats A+ Guide to Hardware, 4e

  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

  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 Propertieson 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 Fdisk A+ Guide to Hardware, 4e

  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 covered A+ Guide to Hardware, 4e

  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 standard A+ Guide to Hardware, 4e

  23. Table 7-1 Summary of ATA interface standards for storage devices A+ Guide to Hardware, 4e

  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 external A+ Guide to Hardware, 4e

  25. Figure 7-16 A PC’s hard drive subsystem using parallel ATA A+ Guide to Hardware, 4e

  26. Figure 7-18 A hard drive subsystem using the new serial ATA data cable A+ Guide to Hardware, 4e

  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 controller A+ Guide to Hardware, 4e

  28. Figure 7-21 The 137-GB barrier existed because of the size of the numbers used to address a sector A+ Guide to Hardware, 4e

  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

  30. Figure 7-22 A motherboard has two IDE channels; each can support a master and slave drive using a single EIDE cable A+ Guide to Hardware, 4e

  31. Figure 7-25 Rear of a serial ATA drive and a parallel ATA drive A+ Guide to Hardware, 4e

  32. SCSI Technology • Small Computer System Interfacestandards • 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 devices A+ Guide to Hardware, 4e

  33. Figure 7-28 Using a SCSI bus, a SCSI host adapter can support internal and external SCSI devices A+ Guide to Hardware, 4e

  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

  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 bus A+ Guide to Hardware, 4e

  36. Figure 7-31 This CrossFire hard drive holds 160GB and uses a 1394a or USB 2.0 connection A+ Guide to Hardware, 4e

  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 motherboard A+ Guide to Hardware, 4e

  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 firmware A+ Guide to Hardware, 4e

  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 precautions A+ Guide to Hardware, 4e

  40. Figure 7-32 Plan for the location of drives within bays A+ Guide to Hardware, 4e

  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 cover A+ Guide to Hardware, 4e

  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 housing A+ Guide to Hardware, 4e

  43. Figure 7-41 Connect a power cord to each drive A+ Guide to Hardware, 4e

  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 Format A+ Guide to Hardware, 4e

  45. Figure 7-45 Standard CMOS setup A+ Guide to Hardware, 4e

  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 recognized A+ Guide to Hardware, 4e

  47. Figure 7-48 This motherboard has four serial ATA connectors A+ Guide to Hardware, 4e

  48. Figure 7-49 American Megatrends, Inc. CMOS setup screen shows installed drives A+ Guide to Hardware, 4e

  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 bay A+ Guide to Hardware, 4e

  50. Figure 7-52 Hard drive installed in a wide bay using a universal bay kit adapter A+ Guide to Hardware, 4e

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