PC Hardware

Tutorial 8

What is the purpose of an IDE drive?

The IDE (Integrated Drive Electronics) drive was introduced in the early 1990s. The IDE quickly became the standard for general-purpose computers. The purpose of the IDE specification was to increase data throughput, support non-hard disk drive storage devices, increase the capacity of hard drives beyond the 528-MB barrier, and to allow connection of up to four devices instead of only two.

  1. How many drives can be connected to a single IDE connector?

    Two drives can be connected to one IDE connector.

  2. What is the best method of determining the number of drives available on a computer?

    The best method of determining the number of drives available on a computer is to run the CMOS setup program. Originally, the CMOS would only allow for two drives. Later versions allow up to four drives.

  3. What three things should be checked when a floppy disk drive fails?

    Three things to check when a floppy disk drive fails are the floppy disk itself (not the drive), the CMOS setup, and the drive controller/power supply cables.

  4. What is the best way to ensure long life from a floppy disk drive?

    To ensure long life from a floppy disk drive, keep it clean.

  5. When you purchase a new floppy disk drive controller, what can you expect to receive with it?

    Floppy disk drive controller cards also include some or all of the following: hard disk drive controllers, serial ports, parallel ports, and game ports. If the new card contains any ports that duplicate ports already present elsewhere on the computer (on the motherboard, for instance), a potential conflict exists.

  6. Other than physical size, what are the only differences between a 5.25-inch floppy disk drive and a 3.5-inch floppy disk drive?

    The only difference between a 5.25-inch and a 3.5-inch drive (other than physical size) is that a 5.25-inch drive has a slot connector and a 3.5-inch drive has a pin connector for engaging and spinning the disk.

  7. What type of cable is used to connect a floppy disk drive to the external data bus?

    All floppy disk drives are connected to the motherboard (external data bus) by a 34-conductor ribbon cable. This cable has a seven-wire twist in lines 10 through 16. This ensures that when two floppy disk drives are attached, the drive-select and motor-enable signals on those wires can be inverted to "select" which drive becomes the active target. The other wires carry data and ground signals.

  8. What is the proper way to install a floppy disk drive cable?

    The connector end of the cable, with the twist, always goes toward the drives.

  9. To which pin must the Number 1 wire of the floppy disk drive control cable be connected?

    This red (or sometimes blue) wire is connected to the number 1 pin on the drive's controller connector. (The number 1 pin is usually located next to the power connection.)

  10. You've received the following error message: "General failure reading Drive A:". What is the most likely problem?

    The CMOS settings for the A drive are the most likely cause. Always double-check the CMOS if you are experiencing a recurrent drive failure. Checking is quick, easy, and can save you time.

  11. Are floppy disk controllers sensitive to ESD?

    Yes, floppy disk controllers are sensitive to ESD (electrostatic discharge).

  12. You receive an error message that ends with "Abort, Retry, Fail?" What is the most likely cause of the error?

    This error message indicates a failure to read the drive. These errors are the easiest to fix and can usually be attributed to a bad sector on the drive.

  13. Why is a voice coil actuator arm better than a stepper motor actuator arm?

    A voice coil actuator arm has several advantages over the stepper motor actuator arm. The lack of mechanical interface between the actuator arm and the motor provides consistent positioning accuracy. When the drive is shut down (the power is removed from the coil), the actuator arm (which is spring-loaded) moves back to its initial position, thus eliminating the need to park the head. In a sense, these drives are self-parking.

  14. Define hard disk drive geometry.

    Hard disk drives are composed of one or more disks, or platters, on which data is stored. The geometry of a hard drive is the organization of data on these platters. Geometry determines the maximum storage capacity of the drive.

  15. What is the best way to determine the geometry of an unknown drive?

    The geometry or type of many hard disk drives is labeled directly on the hard drive itself.

  16. Describe HDI.

    Head to Disk Interference (HDI) is another term for head crash.

  17. The BIOS limits the number of heads to a maximum of __________.

    The maximum number of heads is 16.

  18. The BIOS limits the number of cylinders to a maximum of __________.

    The maximum number of cylinders is 1024.

  19. How many bytes of data does a sector hold?

    One sector holds 512 bytes of data.

  20. What is the maximum number of sectors per track?

    The maximum number of sectors per track is 63.

  21. What does CHS stand for?

    CHS stands for cylinders, heads and tracks per sector.

  22. What type of drive is standard on today's personal computer?

    The IDE is the standard drive on today's personal computers.

  23. Describe the characteristics of the different hard disk drive types.

    The first hard disk drives for personal computers used the ST-506/412 interface. The ST-506/412 was the only hard drive available for the IBM computer and the first to be supported by the ROM BIOS chip on the motherboard.

    The Enhanced Small Device Interface (ESDI) was introduced in 1983 by the Maxtor Corporation. Beginning with this drive, most controller functions were incorporated directly onto the hard disk drive itself.

    The Small Computer System Interface (SCSI) has been around since the mid 1970s in one or another form. Apple adopted the SCSI as its expansion bus standard. The SCSI bus functions as a communications pathway between the computer system bus and the SCSI device controller.

  24. What is a partition? What are the two types of partition?

    Partitions are logical divisions of a hard disk drive. A computer might have only one physical hard drive (called hard drive 0), but it can have anywhere from one to 24 logical drives, called C to Z.

    There are two types of partitions: primary and extended.

  25. Define a cluster.

    A cluster is a combined set of contiguous sectors which the FAT treats as a single unit. The number of sectors in each cluster is determined by the size of the partition. There can never be more than 64,000 clusters.

  26. What is the FAT and how does it work?

    The FAT (file allocation table) is simply an index that keeps track of which part of the file is stored in which sector. Each partition (or floppy disk) has two FATs stored near the beginning of the partition. These FATs are called FAT 1 and FAT 2. They are identical. Each FAT can be looked at as a two-column spreadsheet.

  27. What is fragmentation?

    Fragmentation is the scattering of parts of the same disk file over different areas of the disk. When files are scattered all over a drive in noncontiguous clusters they are said to be fragmented.

  28. How can you minimize the impact of a hard disk drive failure?

    To minimize the impact of a hard disk drive failure, perform comprehensive, frequent backups, and save a copy of the boot sector and partition table.

  29. What is the function of ScanDisk?

    ScanDisk performs a battery of tests on a hard disk. These include looking for invalid filenames, invalid file dates and times, bad sectors, and invalid compression structures. In the file system, ScanDisk looks for lost clusters, invalid clusters, and cross-linked clusters.