Hard Drive Failure – Symptoms and Troubleshooting

The hard-disk drive (HDD) evolved to answer the incessant demands for permanent highvolume file and data storage in the PC. Early floppy disks provided simple and inexpensive storage, but they were slow and programs quickly became far too large to store adequately on diskettes. Switching between multiple diskettes also proved to be a cumbersome proposition. By the early 1980s, hard drives had become an important part of PC architecture (Fig. 17-1) and helped to fuel further OS and applications development. Today, the hard drive is an indispensable element of the modern PC. The hard drive holds the operating system, which boots the system, stores the multi-megabyte applications and files that we rely on, and even provides “virtual memory” for systems lean on RAM. Hard-drive performance also has a profound effect on overall system performance. As you might imagine, hard-drive problems can easily cripple a system. This chapter presents the technology and principles of hard-disk drives, and provides you with some solutions for drive testing and troubleshooting.

Drive Concepts

The first step in understanding hard drives is to learn the basic concepts involved. Many of the terms covered in Chapter 16 also apply to hard drives, but the additional performance requirements and operating demands placed on hard drives have resulted in an array of important new ideas. In principle, a hard-disk drive is very similar to a floppy drive—a magnetic recording media is applied to a substrate material, which is then spun at a high rate of speed. Magnetic read/write heads in close proximity to the media can step rapidly across the spinning media to detect or create flux transistions, as required. When you look closely, however, you can see that there are some major physical differences between floppy and hard drives.

Platters and Media 

Where floppy disks use magnetic material applied over a thin, flexible substrate of mylar(or some other plastic), hard drives use rugged, solid substrates, called platters. You canclearly view the platters of a hard drive in Fig. 17-2. A platter is traditionally made of alu-

Power-Mode Definitions

Modern hard drives are not simply “on” or “off.” They operate in any one of several modes, and each mode makes different power demands on the host system. This is particularly important because today’s PCs are becoming ever-more power conscious, so the ability to control drive power is an integral part of PC power-conservation systems.

Typical hard drives operate in any of five different power modes:

·         Spin-up The drive is spinning up following initial application of power and has not yet reached full speed. This demands about 14 W and is particularly demanding of the power supply (if the supply is marginal or overloaded, the hard drive might not spin-up properly).

·         Seek This is a random-access operation by the disk drive as it tries to locate the required track for reading or writing. This demands about 8.5- to 9.0 W.

·         Read/write A seek has been completed, and data is being read from or written to the drive. This uses about 5.0 W.

·         Idle This is a basic power-conservation mode, where the drive is spinning and all other circuitry is powered on, but the head actuator is parked and powered off. This drops power demands to about 4 W, yet the drive is capable of responding to read commands within 40 ms.

·         Standby The spindle motor is not running (the drive “spins down”). This is the main power-conservation mode, and it requires just 1 W. It might require up to several seconds for the drive will leave this mode (or spin-up) upon receipt of a command that requires disk access.

Smart Command Set

Some of the newest hard drives use the Self-Monitoring Analysis and Reporting Technology (SMART) command set. SMART-compliant drives improve the data integrity anddata availability of hard-disk drives by regularly checking for potential drive problems. Insome cases, a SMART-compliant device will predict an impending failure with sufficienttime to allow users to backup their data and replace the drive before data loss occurs.

Drive Testing and Troubleshooting

Hard-disk drives present some perplexing challenges for computer technicians and every day users alike. The problem with hard drives is that they are inaccessible devices. Unless you have the cleanroom environment to open the sealed drive platters, it is pointless to even consider replacing failed drive mechanics. Even if you could open a drive safely, the advances in hard-drive technology have been so fast and furious that no spare parts market has ever developed. Drive manufacturers themselves rarely bother to repair faulty drives or invest in specialized drive-testing equipment. Clearly, the course for hard-drive repair is to identify defective drives and replace faulty units with new (usually better) ones. Fortunately, not all hard-drive problems are necessarily fatal. True, you might lose some programs and data (backup your hard drive frequently), but many drive problems are recoverable without resorting to drive replacement. Instead of focusing on repairing a hard drive’s electronics or mechanics, today’s repair tactics focus on repairing a drive’s data. By reconstructing or relocating faulty drive information, it is often possible to re-

The important thing to remember when using this workaround is that you must keep a record of the translation values used so that they can be re-entered if the contents of CMOS RAM are lost, or if the drive is moved to another system. Write the values on masking tape and stick the tape on the drive itself. cover from a wide variety of drive problems. Before you begin any sort of drive troubleshooting, you should take the following steps:

·         Gather a DOS boot disk or Windows 95 startup disk (refer to the end of Chapter 3). If you don’t have a boot disk on hand, you should make one before continuing.

·         Gather your DOS installation disk(s) or Windows 95 CD-ROM—if you need to reinstall the operating system, these will be invaluable.

·         Gather any hard drive/controller diagnostics that you’ll need.

·         Backup as much as you can from your hard drive(s) before attempting any sort of drive service.

Hdd-Controller Bios Error Codes

There might be times when your hard-drive controller fails or cannot communicate properly with the hard drive. When this occurs, you’ll often find that the controller returns an error code. Table 17-9 lists a selection of HDD controller error codes that are

Troubleshooting “DOS Compatibility Mode” Problems

One of the great advantages enjoyed by Windows 95 is that it operates in the “protectedmode”— that is, drivers and software can be executed beyond the traditional “real-mode” RAM limit of 1MB. By comparison, DOS is a real-mode environment. DOS programs and drivers can only be executed within the first 640KB of RAM (the “conventional memory” area). If Windows 95 cannot establish protected-mode operation for a drive, it will fall back to real-mode driver support. This is known as DOS compatibility mode. Unfortunately, real mode support often impairs system performance. If you notice that one or more of the hard drives in a system is using DOS compatibility mode (there might be an error message such as: “Compatibility mode paging reduces overall system performance”), you’ll need to track down and correct the cause. In general, Windows 95 might invoke the DOS compatibility mode for any of the following reasons:

·         A questionable device driver, TSR, or computer virus has hooked the INT 21h or INT 13h chain before Windows 95 loaded.

·         The hard-disk controller in your computer was not detected by Windows 95.

·         The hard-disk controller was removed from the current configuration in Device manager.

·         There is a resource conflict between the hard-disk controller and another hardware device.

·         The Windows 95 protected-mode driver is missing or damaged.

·         The Windows 95 protected-mode driver detected incompatible or unsupportable hardware.

You can use the following procedure to isolate and correct the cause of DOS compatibility mode problems: 

1.      Open the Control panel, double-click the System icon, then choose the Performance tab in the System properties dialog. You can identify which drive is using DOS compatibility mode and why.

2.      If the driver name listed as causing the DOS compatibility mode is: MBRINT13.SYS, your computer might be infected with a boot-sector virus or you are running real-mode disk overlay software (for an IDE hard disk with more than 1024 cylinders) that is not compatible with Windows 95 protected-mode disk drivers.

·         Run a recent anti-virus program to detect and remove boot-sector viruses (such as Norton Anti-Virus, NAV). You might need to rewrite your boot sector using a DOS command, such as FDISK /MBR.

·         If you cannot detect any virus activity, check the disk-management software. Be sure that you’re using Disk Manager 7.0 or later (use Disk Manager 7.04 if you’re running DriveSpace 3, included with the Microsoft Plus! pack).

3.      If the driver name that is listed is in the CONFIG.SYS file, contact the driver’s manufacturer to determine whether there is a more recent version of the driver that allows protected-mode operation in Windows 95. You might be able to download the latest driver version from the driver manufacturer’s Web site.

4.      If no driver is listed on the Performance tab, check that the hard-disk controller is listed in the Device manager. If not, install it through the Add new hardware wizard. If the wizard cannot detect the controller automatically, run the wizard again, but do not let it attempt to detect the hardware in your computer—instead, select the controller specifically from the hardware list. If your particular controller is not listed, contact the manufacturer of the disk controller to obtain a Windows 95 protected-mode disk driver (or a Windows 3.1x 32-bit disk access (FastDisk) driver, if available). 

5.      If the hard-disk controller is listed in the Device manager, but has a yellow “!” over it, there is a resource conflict (IRQ, I/O, DMA, or BIOS address range) with another device, the protected-mode driver is missing or damaged, or the Disable all 32-bit protected-mode disk drivers check box has been selected in File system properties.

·         Doubleclick the System icon in the Control panel, click the Performance tab, then click File system. Select the Troubleshooting tab and see that the Disable all 32-bitprotected- mode disk drivers check box has not been selected.

·         Resolve any resource conflicts with other devices in the system (refer to Chapter 10).

·         Check that the protected-mode driver is in the Windows\SYSTEM\IOSUBSYS directory and is loading properly. To find which driver is providing 32-bit disk access, click Properties for the disk controller in Device manager and click the Driver tab to see which driver files are associated with the controller. For most IDE, EIDE, and ESDI disk controllers, 32-bit disk access is provided by the ESDI_506.PDR driver.

For SCSI controllers, Windows 95 often uses SCSIPORT.PDR and a “mini port” (or .MPD) driver. Restart Windows 95, press <F8> when the “Starting Windows 95” message appears, then select a “Logged” (BOOTLOG.TXT) start. If the 32-bit driver is listed as loading properly, you’re all set. Otherwise, the driver might be missing or damaged—try reinstalling the respective 32-bit drivers.

6.       Load SYSTEM.INI into a text editor and check to see if the MH2BIT.386 driver is being loaded (check for a line that reads: “device=mh32bit.386”). This driver is installed by MicroHouse EZ-Drive software, and is not compatible with the Windows 95 protected mode disk drivers. Unfortunately, this driver is not removed by Windows 95 Setup, so you’ll need to disable the line manually, save your changes, and reboot the PC.

7.       If all else fails, you might be able to achieve protected-mode support from the disk controller by disabling any of the controller’s advanced features (i.e., caching, fast or “turbo” modes), or reducing data-transfer rates. You might also try systematically disabling advanced IDE controller features in the CMOS setup.

8.       `If problems persist, you might have to replace the drive controller with a model that better supports protected-mode operation.

Symptoms and Solutions

Now it’s time to take a look at some problems and solutions. The important concept here is that a hard-drive problem does not necessarily mean a hard-drive failure. The failure of a

Drive Testing and Troubleshooting 623

If the hard-disk controller is listed in Device manager, but has ared “X” over it, it has been removed from the current hardware profile. Click Properties for the controller in Device manager, then click the check box that corresponds to the current hardware profileunder Device usage.Sector or track does not automatically indicate physical head or platter damage—that is whysoftware tools have been so successful. Even if one or more sectors are physically damaged,millions of sectors are on a hard drive. A few bad sectors do not render a drive faulty.

One of the only times that a drive is truly irreparable is when physical media damage occurs on track 00, but software tools will help you to identify the scope of the problem.

Symptom 17-1. The hard drive is completely dead The drive does not spin up, the drive light doesn’t illuminate during power-up, or you see an error message indicating that the drive is not found or ready. In most cases, you should suspect a power problem first. Be sure that the 4-pin power connector is inserted properly and completely. If the drive is being powered by a “Y-connector,” be sure any interim connections are secure.

Use a voltmeter and measure the +5-V (pin 4) and +12-V (pin 1) levels. If either voltage (especially the +12-V supply) is unusually low or absent, replace the power supply. Also check your signal cable. See that the drive’s signal interface cable is connected securely at both the drive and controller ends. For IDE/EIDE drives, this is the 40-pin ribbon cable.

If the cable is visibly worn or damaged, try a new cable. The PC cannot use a hard drive that it can’t recognize, so enter the CMOS setup routine and see that all of the parameters entered for the drive are correct. Heads, cylinders, sectors per track, landing zone, and write precompensation must all be correct—otherwise, POST will not recognize the drive. If you have an “auto-detect” option available, try that also. Remember to save your changes in CMOS and reboot the system. If problems continue, the hard drive itself might be defective. Try a known-good hard drive. If a known-good drive works as expected, your original drive is probably defective, and should be replaced. If a known-good hard drive fails to operate, replace the drive controller board.

Symptom 17-2. You see drive activity, but the computer will not boot from the hard drive In most cases, there is a drive failure, boot-sector failure, or DOS/Windows file corruption. Check the signal cable first. Be sure that the drive’s signal interface cable is connected securely at both the drive and controller. If the cable is visibly worn or damaged, try a new one. You should check the CMOS setup next—see that all of the parameters entered for the drive are correct. Heads, cylinders, sectors per track, landing zone, and write precompensation must all correct. Otherwise, POST will not recognize the drive. If it has an option to “auto-detect” the drive, try that as well.

The boot sector might also be defective. Boot from a floppy disk and try accessing the hard drive. If the hard drive is accessible, chances are that the boot files are missing or corrupt.

Try a utility, such as DrivePro’s Drive Boot Fixer or DISKFIX with PC Tools. You might also try running “FDISK /MBR,” which will rebuild the drive’s master boot record.

Careful: the FDISK /MBR command might render the files on your drive inaccessible. Finally, you might have a problem with your drive-system hardware. If you cannot access the hard drive, run a diagnostic such as Windsor Technologies’ PC Technician. 

Test 624 Hard Drives

Drive troubleshooting has the potential of destroying any data on the drive(s). Before attempting to troubleshoot hard-disk problems, be sure to back up as much of the drive as possible. If no backup is available, do not repartition or reformat the drive unless absolutely necessary, and all other possible alternatives have been exhausted. the drive and drive controller. If the controller responds, but the drive does not, try repartitioning and reformatting the hard drive. If the drive still doesn’t respond, replace the hard drive outright. If the controller doesn’t respond, replace the hard-drive controller.

Symptom 17-3. One or more sub-directories appear lost or damaged Both the root directory of a drive and its FAT contain references to sub-directories. If data in either the root directory or file allocation table is corrupt, one or more sub-directories might be inaccessible by the drive. Try repairing the drive’s directory structure. Use DISKFIX (with PC Tools) or SCANDISK (with DOS 6.2 or later) to check the disk’s directory structure for problems. 

Symptom 17-4. Errors occur during drive reads or writes Magnetic information does not last forever, and sector ID information can gradually degrade to a point where you encounter file errors. Start by checking for file structure problems on the drive. 

Use a utility, such as DISKFIX or SCANDISK, to examine the drive and search for bad sectors. If a failed sector contains part of an .EXE or .COM file, that file is now corrupt and should be restored from a backup. If you cannot isolate file problems, you might need to consider a Low-Level (LL) format. This is an ideal solution because LL formatting rewrites sector ID information, but the sophistication of today’s drives makes LL formatting almost impossible. If the drive manufacturer provides a “drive preparation” utility, you should backup the drive, run the utility, FDISK, FORMAT, and restore the drive. Symptom 17-5. The hard drive was formatted accidentally A high-level format does not actually destroy data, but rather it clears the file names and locations kept in the root directory and FAT— this prevents DOS from finding those files. You will need to recover those files. Use a utility, such as UNFORMAT (with PC Tools), which can reconstruct root directory and FAT data contained in a MIRROR file. This is not always a perfect process and you might not be able to recover all files.

Symptom 17-6. A file has been deleted accidentally Mis-typing or forgetting to add a drive specification can accidentally erase files from places you did not intend to erase. You can often recover those files if you act quickly. Use a utility, such as UNDELETE (with PC Tools and DOS), to restore the deleted file. This is not always a perfect process and you might not be able to recover every file.

Symptom 17-7. The hard drive’s root directory is damaged A faulty root directory can cripple the entire disk, rendering all sub-directories inaccessible. You might be able to recover the root directory structure. Use a utility, such as DISKFIX (with PC Tools), to reconstruct the damaged FATs and directories. If you have been running MIRROR, DISKFIX should be able to perform a very reliable recovery. You might also try other recovery

Drive Testing and Troubleshooting 625ATA AND TROUBLESHOOTING

In order for MIRROR data to be useful, do not save new files before running UNFORMAT. In order for UNDELETE to be useful, do NOT save new files before running UNDELETE. utilities, such as DrivePro or ScanDisk. However, if you cannot recover the root directory reliably, you will need to reformat the drive, then restore its contents from a backup.

Symptom 17-8. Hard drive performance appears to be slowing down over time In virtually all cases, diminishing drive performance can be caused by file fragmentation. To a far lesser extent, you might be faced with a computer virus. Start the PC with a “clean” boot disk and be sure that no TSRs or drivers are being loaded. After a clean boot, run your antivirus checker and be sure that there are no memory-resident or file-based viruses. If the system checks clean for computer viruses, you should check for file fragmentation next. Start your defragmentation utility (such as COMPRESS with PC Tools or DEFRAG with DOS) and check to see the percentage of file fragmentation. If it has more than 10% fragmentation, you should consider running the defragmentation utility after preparing Windows. Before defragmenting a drive, reboot the system normally, start Windows, access the Virtual memory controls for your version of Windows, and shut down virtual memory. Then leave Windows and boot the system “clean” again. Restart your defragmentation utility and proceed to defragment the disk. This process might take several minutes, depending on the size of your drive. Once defragmentation is complete, reboot the system normally, start Windows, access the Virtual memory controls for your version of Windows, and recreate a permanent swap file to support virtual memory. You should now notice a performance improvement. 

Symptom 17-9. The hard drive accesses correctly, but the drive light stays on continuously A continuous LED indication is not necessarily a problem as long as the drive seems to be operating properly. Check the drive and drive controller for drive “light jumpers”— examine the drive itself for any jumper that might select Latched mode vs. Activity mode. If no such jumpers are on the drive, check the drive controller or motherboard. Set the jumper to Activity mode to see the drive light during access only. 

Next, consider the possibility of drive-light error messages. Some drive types (especially SCSI drives) use the drive-activity light to signal drive and controller errors. Check the drive and controller documents and see if any error is indicated by the light remaining on.

Symptom 17-10. The hard drive is not accessible and the drive light stays on continuously This usually indicates a reversed signal cable, which is most common when upgrading or replacing a drive system. In virtually all cases, one end of the signal cable is reversed. Be sure that both ends of the cable are installed properly (remember that the red or blue stripe on one side of the cable represents pin 1). If problems persist, replace the drive controller. It is rare for a fault in the drive controller to cause this type of problem, but if trouble persists, try a known-good drive controller board.

Symptom 17-11. A “No fixed disk present” error message appears on the monitor This kind of problem can occur during installation, or at any point in the PC’s working life. Check the power connector first, and be sure the 4-pin power connector is inserted properly and completely. If the drive is being powered by a Y-connector, be sure any interim connections are secure. Use a voltmeter and measure the +5-V (pin 4) and +12-V (pin 1) levels. If either voltage (especially the +12-V supply) is unusually low or absent, replace the power supply. Next, check the signal connector. Be sure that the ’s signal cable is connected securely at both the drive and controller. If the cable is visibly worn or damaged, try a new one.

If problems persist, check the CMOS setup—enter the CMOS setup routine and see that all of the parameters entered for the drive are correct. Heads, cylinders, sectors per track, landing zone, and write precompensation must all correct—otherwise, POST will not recognize the drive. You might also try “auto-detecting” the drive. Also check for hardware conflicts.

Be sure that no other expansion devices in the system use the same IRQs or I/O addresses used by your drive controller. If so, change the resources used by the conflicting device. If your drive system uses a SCSI interface, be sure that the SCSI cable is terminated properly. If problems continue, try a known-good hard drive. If a known-good drive works as expected, your original drive is probably defective. If problems persist with a known-good hard drive, replace the drive-controller board.

Symptom 17-12. The drive spins up, but the system fails to recognize it Your computer might flag this as a “Hard-disk error” or “Hard-disk controller failure” during system initialization. Start by checking the signal connector. Be sure that the interface signal cable is inserted properly and completely at the drive and controller. Try a new signal cable. Next, check any drive jumpers, and see that a primary (master) drive is configured as primary, and a secondary (slave) drive is configured as secondary. For SCSI drives, see that each drive has a unique ID setting and check that the SCSI bus is terminated properly.

Enter the CMOS setup routine and see that all of the parameters entered for the drive are correct. Heads, cylinders, sectors per track, landing zone, and write precompensation must all correct—otherwise, POST will not recognize the drive. Try using the “auto-detect” feature if it is available. If the CMOS is configured properly, you should suspect a problem with the partition. Boot from a floppy disk and run FDISK to check the partitions on your hard drive.

Be sure that there is at least one DOS partition. If the drive is to be your boot drive, the primary partition must be active and bootable. Repartition and reformat the drive, if necessary 

If problems persist, try a known-good hard drive. If a known-good drive works as expected, your original drive is probably defective. If a known-good hard drive fails to work as expected, replace the drive controller. If problems persist with a known-good floppy drive, replace the drive-controller board.

Symptom 17-13. The IDE drive spins up when power is applied, then rapidly spins down  gain The drive is defective, or it is not communicating properly with its host system. Check the power connector first. Be sure that the 4-pin power connector is inserted properly and completely into the drive. Always check the signal connector next, and see that the interface signal cable is inserted properly and completely at the drive and controller. Try a new signal cable.

Inspect the drive jumpers—the primary (master) drive should be configured as primary, and a secondary (slave) drive should be configured as secondary. For SCSI drives, see that each drive has a unique ID setting, and check that the SCSI bus is terminated properly. If problems persist, try a known-good hard drive. If a known-good drive works as expected, your original drive is probably defective.

Symptom 17-14. A “Sector not found” error message appears on the monitor This problem usually occurs after the drive has been in operation for quite some time, and is typically the result of a media failure. Fortunately, a bad sector will only affect one file. Try recovering the file. Use a utility, such as SpinRite (from Gibson Research) or another data-recovery utility, and attempt to recover the damaged file. Notice that you might be unsuccessful, and have to restore the file from a backup later. Check the media itself. Use a disk utility, such as ScanDisk, to evaluate the drive, then locate and map out any bad sectors that are located on the drive.

If problems persist, perform a low-level format (if possible). Lost sectors often occur as drives age and sector ID information degrades. LL formatting restores the sector IDs, but LL formatting is performed at the factory for IDE/EIDE and SCSI drives. If an LL formatting utility is available for your particular drive (available right from the drive manufacturer), and ScanDisk reveals a large number of bad sectors, you might consider backing up the drive completely, running the LL utility, repartitioning, reformatting, then restoring the drive. 

Finally, if ScanDisk maps out bad sectors, you might need to restore those files from a backup.

Symptom 17-15. A “1780 or 1781 ERROR” appears on the monitor The classic 1780 error code indicates a “Hard disk 0 failure,” and the 1781 error code marks a “Hard disk 1 failure.” Start the PC with a “clean” boot disk and be sure that no TSRs or drivers are being loaded. If you haven’t done so already, run your anti-virus checker and be sure that there are no memory-resident or file-based viruses. Next, if you can access the hard drive once your system is booted, chances are that the boot files are missing or corrupt.

Try a utility, such as DrivePro’s Drive Boot Fixer or DISKFIX with PC Tools. Otherwise, you will need to repartition and reformat the disk, then restore disk files from a backup. Check the hardware next—if you cannot access the hard drive, run a diagnostic such as Windsor Technologies’ PC Technician. Test the drive and drive controller. If the controller responds but the drive does not, try repartitioning and reformatting the hard drive. If the drive still doesn’t respond, replace the hard drive outright. If the controller doesn’t respond, replace the hard-drive controller.

Symptom 17-16. A “1790 or 1791 ERROR” appears on the monitor The classic 1790 error code indicates a “Hard Disk 0 Error,” although the 1791 error code marks a “Hard Disk 1 Error.” Check the signal connector first. Be sure that the interface signal cable is inserted properly and completely at the drive and controller. Try a new signal cable. There might also be a problem with the drive’s partition. Boot from a floppy disk and run FDISK to check the partitions on your hard drive. Be sure that there is at least one DOS partition. If the drive is to be your boot drive, the primary partition must be active and bootable. Repartition and reformat the drive, if necessary.

If problems persist, replace the hard drive. If a known-good drive works as expected, your original drive is probably defective. If problems persist with a known-good floppy drive, replace the drive-controller board.

Symptom 17-17. A “1701 ERROR” appears on the monitor The 1701 error code indicates a hard-drive POST error—the drive did not pass its POST test. Check the power connector first, and be sure that the 4-pin power connector is inserted properly and completely. If the drive is being powered by a Y connector, be sure that any interim connections are secure. Use a voltmeter and measure the +5-V (pin 4) and +12-V (pin 1) levels.

If either voltage (especially the +12-V supply) is unusually low or absent, replace the power supply. Enter the CMOS setup routine and see that all of the parameters entered for the drive are correct. Heads, cylinders, sectors per track, landing zone, and write precompensation must all correct; otherwise, POST will not recognize the drive. Try “autodetecting” the drive. If problems persist, perform a low-level format (if possible). ST506/412 and ESDI drives might require LL formatting, but LL formatting is performed at the factory for IDE/EIDE and SCSI drives. If an LL-formatting utility is available for your particular drive (available right from the drive manufacturer), you might consider backing up the drive completely, running the LL utility, repartitioning, reformatting, then restoring the drive.

Symptom 17-18. The system reports random data, seek, or format errors Random errors rarely indicate a permanent problem, but identifying the problem source can be a timeconsuming task. Check the power connector first. Be sure that the 4-pin power connector is inserted properly and completely. If the drive is being powered by a “Y-connector,” be sure that any interim connections are secure. Use a voltmeter and measure the +5-V (pin 4) and +12-V (pin 1) levels. If either voltage (especially the +12-V supply) is unusually low, replace the power supply.

Check the signal connector next. Be sure that the interface signal cable is inserted properly and completely at the drive and controller. Try a new signal cable. Also try re-routing the signal cable away from the power-supply or “noisy” expansion devices. Check the drive orientation. If problems occur after remounting the drive in a different orientation, you might need to repartition and reformat the drive, or return it to its original orientation.

Try relocating the drive-controller away from cables and “noisy” expansion devices. If your system has a “turbo” mode, your ISA drive controller might have trouble operating while the system is in turbo mode. Take the system out of turbo mode. If the problem disappears, try a new drive controller. The media might also be defective. Use a utility, such as ScanDisk, to check for and map out any bad sectors. Once bad sectors are mapped out, you might need to restore some files from your backup.

Try the hard drive and controller in another system. If the drive and controller work in another system, excessive noise or grounding problems are probably in the original system.

Reinstall the drive and controller in the original system and remove all extra expansion boards. If the problem goes away, replace one board at a time and retest the system until the problem returns. The last board you inserted when the problem returned is probably the culprit. If the problem persists, there might be a ground problem on the motherboard. Try replacing the motherboard as an absolute last effort.

Symptom 17-19. A “Bad or Missing Command Interpreter” error message appears This is a typical error that appears when a drive is formatted in one DOS version, but loaded with another. Compatibility problems occur when you mix DOS versions.

Start by booting the PC with a “clean” boot disk, and be sure no TSRs or drivers are being loaded. If you haven’t done so already, run your anti-virus checker and be sure that there are no memory-resident or file-based viruses. Finally, be sure that the drive is partitioned and formatted with the version of DOS that you intend to use. Also be sure to use FORMAT with the /S switch, or SYS C: to transfer system files to the drive.

Symptom 17-20. An “Error reading drive C:” error message appears Read errors in a hard drive typically indicate problems with the disk media, but might also indicate viruses or signaling problems. Check the signal connector first. Be sure that the interface signal cable is inserted properly and completely at the drive and controller. Try a new signal cable. Next, start the PC with a “clean” boot disk and be sure that no TSRs or drivers are being loaded. If you haven’t done so already, run your anti-virus checker and be sure that there are no memory-resident or file-based viruses.

Consider the drive’s orientation. If problems occur after remounting the drive in a different orientation, you might need to repartition and reformat the drive, or return it to its original orientation. Also check the media—use a utility, such as ScanDisk, to check for and map out any bad sectors. Once bad sectors are mapped out, you might need to restore some files from your backup. Try a known-good hard drive. If a known-good drive works as expected, your original drive is probably defective.

Symptom 17-21. A “Track 0 not found” error message appears A fault on track 00 can disable the entire drive because track 00 contains the drive’s File Allocation Table (FAT). This can be a serious error, which might require you to replace the drive. Before going too far with this type of problem, check the signal connector and see that the interface signal cable is inserted properly and completely at the drive and controller. Try a new signal cable.

Boot from a floppy disk and run FDISK to check the partitions on your hard drive. Be sure that there is at least one DOS partition. If the drive is to be your boot drive, the primary partition must be active and bootable. Repartition and reformat the drive, if necessary. Try a known-good hard drive. If a known-good drive works as expected, your original drive is probably defective.

Symptom 17-22. Software diagnostics indicate an average access time that is longer than specified for the drive The average access time is the average amount of time needed for a drive to reach the track and sector, where a needed file begins.

Before you do anything else, check the drive specifications and verify the timing specifications for your particular drive. Start your defragmentation utility (such as COMPRESS with PC Tools or DEFRAG with DOS) and check to see the percentage of file fragmentation.

If there is more than 10% fragmentation, you should consider running the defragmentation utility after preparing Windows (see Symptom 8).

Also remember that different software packages measure access time differently. Be sure that the diagnostic subtracts system overhead processing from the access-time calculation.

Try one or two other diagnostics to confirm the measurement. Before you panic and replace a drive, try testing several similar drives for comparison. If only the suspect drive measures incorrectly, you might not need to replace the drive itself just yet, but you should at least maintain frequent backups in case the drive is near failure.

Symptom 17-23. Software diagnostics indicate a slower data transfer rate than specified This is often because of “less-than-ideal” data-transfer rates, rather than an actual hardware failure. Enter the CMOS setup routine and verify that any enhanced data-transfer modes are enabled (such as PIO Mode 3). This can increase data transfer rate substantially. Also check the drive specifications, and verify the timing specifications for your particular drive.

Check for fragmentation next. Start your defragmentation utility (such as COMPRESS with PC Tools or DEFRAG with DOS), and check to see the percentage of file fragmentation.

Broadly speaking a hard disk can fail in four ways that will lead to a potential loss of data:

1.Firmware Corruption / Damage to the firmware zone

2.Electronic Failure 

3.Mechanical Failure 

4.Logical Failure 

Combinations of these four types of failure are also possible. Whether the data on the hard disk is recoverable or not depends on exactly what has happened to the disk and how bad the damage is. All hard disks also develop bad sectors which can lead to data loss and drive inaccessibility.

1.  Firmware Corruption / Damage to the firmware zone

 Hard disk firmware is the information that is used by the computer that allows it to correctly interact with the hard disk. If the firmware of a hard disk becomes corrupted or unreadable the computer is often unable to correctly interact with the hard disk. Frequently the data on the disk is fully recoverable once the drive has been repaired and reprogrammed. 

2.  Electronic Failure

Electronic failure usually relates to problems on the controller board of the actual hard disk. The computer may suffer a power spike or electrical surge that knocks out the controller board on the hard disk making it undetectable to the BIOS. Usually, the data on the hard disk has not suffered any damage and a 100% data recovery is possible. 

3.  Mechanical Failure

Usually worse than electronic failure, mechanical failure can quite often (especially if not acted on early) lead to a partial and sometimes total loss of data. Mechanical failure comes in a variety of guises such as read / write head failure and motor problems. One of the most common mechanical failures is a head crash. Varying in severity, a head crash occurs when the read-write heads of the hard disk come into contact, momentarily or continuously, with the platters of the hard disk. 

Head crashes can be caused by a range of reasons including physical shock, movement of the computer, static electricity, power surges and mechanical read-write head failure.

Mechanical failure can usually be spotted by a regular clicking or crunching noise. It's not necessarily a head crash, the most important things to do if you suspect mechanical problems is to switch off the drive immediately as further use will make matters worse.

4.  Logical Errors

Often the easiest and the most difficult problems to deal with, logical errors can range from simple things such as an invalid entry in a file allocation table to truly horrific problems such as the corruption and loss of the file system on a severely fragmented drive.

Logical errors are different to the electrical and mechanical problems above as there is usually nothing 'physically' wrong with the disk, just the information on it. 

RemedialProcedure

Some of the steps involved in the remedy of the Hard drive failure are given below:

1.      The first thing to check for is whether or not the hard disk can be seen by the hard disk controller; usually on a true hard disk failure, the disk will not be detectable by the controller (but this is not always the case). Assuming you have an IDE hard disk, enter the BIOS setup program and use the IDE detection facility of the BIOS to see if the disk's parameters can be detected. If the disk cannot be auto detected using the auto detect feature in the BIOS program implies immediately some sort of hardware problem. 

2.      If you can see the hard disk when you auto detect, the problem is more likely to be software than hardware. Remember that you cannot usually boot a brand new hard disk until it has been partitioned and formatted. 

3.      See if the disk will boot up. If it will not boot, then boot from a floppy boot disk and then use the FDISK command (or other partitioning software) to see if you can see the disk. 

4.      If the drive will boot up, then you should be getting a more specific error message of some sort, or a more specific failure mode that you can use for troubleshooting. 

5.      If the drive is detected in the BIOS setup but cannot be booted or accessed when booting from a floppy disk, then there is a good chance that the disk itself may be bad. If possible, try connecting the hard disk to another system and see if the problem is present there as well.

1)       If the hard disk is dead and needs to be replaced follow the procedure given below:

a)      Remove the screws that hold the drive in the bay.

b)      Remove the defective hard disk

c)      Remove the IDE cable

d)      Select a good hard disk, connect the IDE cable and replace the hard disk. 

e)      Secure the hard disk on the drive bay slot by tightening the screws. 

Scandisk:

This is a maintenance procedure built into the Windows operating system that checks the hard drive to determine if there is physical damage or damage to the file system.

If the computer reports that it has corrupted, damaged, or missing files and the programs no longer operate properly, then this is the first step to try and fix the problem. Also, if the computer seems to be running slower than usual, sometimes this procedure will provide a fix. It is a good idea to perform this operation often.

Scandisk Procedure

1.                  Temporarily deactivate any screen saver. Click on START then SETTINGS then CONTROL PANEL then DISPLAY then SCREEN SAVER. Set the Screen Saver to NONE and click OK. 

2.                  Click on START then PROGRAMS then ACCESSORIES then SYSTEM TOOLS then SCANDISK.

NOTE - Depending on what version of Windows you are running the above labels may be slightly different, but not so different that you will not be able to find it.

The following window will open on your screen.

3.   Be sure to select "C:" from the drop down box if it is not already chosen. Then click on the radio button for Standard under Type of test. Next check the box (click on it) labelled Automatically fix errors.

The Thorough test option should not be selected unless you suspect the physical hard drive has been damaged. I suggest always running the Standard scandisk option first. Then If you still have problems rerun it with the Thorough option selected. Also, if you do not select Automatically fix errors the computer will stop and wait for you to answer some rather confusing questions. 

4.    Click on the button labelled Advanced... to launch the following sub-window.
5.    Be sure to click on all of the radio buttons and check boxes EXACTLY as shown.
Then     press the OK button. This will return you to the former screen where you can press
START.

The Scandisk process usually does not take lon

g unless there are serious problems with the hard drive. Do not be concerned if the procedure restarts itself.

6.   When the entire procedure is completed, you can reactivate the screen saver and then start working with applications. It is not necessary to restart the computer.

Reformatting a Hard disk

This procedure explains how to setup a new hard disk. 

Warning - if you are setting up a hard disk which contains data, the following procedure would completely erase your hard disk and the data would be unrecoverable.

Before a new hard disk can be used it needs to be setup. This involves partitioning and formatting the hard disk. Windows 98 or ME boot disk contains the required software to perform this procedure. FDISK.EXE and FORMAT.COM are the files required in your bootable floppy disk. 

1.  Start the partition and format procedure by booting your PC using a Windows boot disk. 

2.  Make sure you set the BIOS so that the boot sequence is set to detect the floppy disk first.

     If your system has no problems booting you will be presented with a Windows boot disk

     menu. This gives you the option to start the system with or without CD-

3.  ROM support. Choose the option to boot without CD-ROM support. You should end up in the MS DOS prompt A: (A drive). 

4.   From A: command prompt type fdisk. You will be presented 

5.  Choose "Y" to enable large disk support.You will now be presented with the FDISK main menu as shown below. 

6.         From the menu, choose option 1 - Create DOS partition or Logical DOS drive.

Another menu will present the following options. 

7.         Choose option 1 - Create primary DOS Partition. FDISK verifies the integrity of your drive and will ask you if want to use the maximum available size of your hard disk to create the primary partition and set it active. To keep things simple we will create one large partition.  

8.         Choose "Y" to use maximum available space. When the partition has been created successfully you will be notified by the system. Your drive is now known as C: (C drive). Press "Esc" to return to the menu. Press "Esc" again to exit FDISK. You need to restart your system for the changes to take affect. Leave boot disk in the drive. 

9.         When the system reboots, choose start without CD-ROM from the boot disk menu. While booting from floppy disk you might get error message like "Invalid media type reading drive C" this is OK for this stage as the hard disk is not formatted.

10.         From A: command prompt type format c:

11.         You will get a message saying "WARNING, ALL DATA ON NONREMOVABLE DISK DRIVE C: WILL BE LOST. Proceed with Format (Y/N)?". 

12.         Since you do not have any data in the new hard disk. Choose "Y". The format will proceed showing a progress indicator. The time it takes to format a hard disk depends on the size and speed of the drive. This could be around 5-30 minutes. Restart  system after format is complete.

13.         Install an operating system.  

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