The following article is first in a series that helps solve many of common boot problems with hard drives. The article explains how to verify drive functionality, determine correct setup for drive, and repair problems with Master Boot Sector once drive is verified to be functional. This information will help solve some very common problems encountered in a computer service department. This article is designed to work with a system that has a single drive with one bootable partition using a FAT 16 structure (all DOS and older Windows systems), and no drive overlay.
It is extremely important not to make or write any changes to data on hard drive without first verifying hard drive configuration. Therefore, first priority when unable to access information on a hard drive is to verify all of configuration information dealing with suspect hard drive.
Partition Parameter Value or Equation Partition Status Bootable Starting Head 1 Starting Sector 1 Starting Cylinder 0 Partition Type Bigdos (drives greater than 30 MB), otherwise DOS 12 Ending Head Total Number of Heads -1 Ending Sector Sectors per Track displayed in Volume Boot Sector Ending Cylinder Number of Cylinders set in CMOS - 2 Total # of Sectors Number of Sectors displayed in Volume Boot Sector Start Absolute Sector Number of Sectors per Track in Volume Boot Sector Boot Signature 55AA
Step One: Make sure that Micro-Scope detects hard drive
In Micro-Scope, System Configuration, Compare Settings - check to make sure that there is not an asterisk beside number of hard drives detected value. If there is an asterisk, either CMOS is set incorrectly, or there is an electronic problem (controller, cable, drive).
Step Two: Compare BIOS parameters against drive partition information.
In Micro-Scope, System Configuration, System Information - note information displayed for hard drive, specifically parameters for drive in question. Compare these parameters to parameters in MBR display under Micro-Scope, System Configuration, Partition Display using following formula:
System Information Master Boot Record Cylinders Ending Cylinder + 2 Heads Ending Head + 1 Sectors Sectors Per Track
If information does not match, either partition information is corrupt, or CMOS setup or controller BIOS setup (if one exists) is incorrect, or there is a problem communicating with drive.
Step Three: Check drive functionality
In Micro-Scope, Diagnostics, Fixed Disk Tests - check information in Fixed Disk Selected window. Make sure that proper drive type, model, and native parameters are showing in this window. If any of information is incorrect, there is an electronic problem. Check cable, controller and drive, re-seating all connections, and repeat above procedure. After correcting electronic problem, perform a read test on first 10 cylinders of drive. If any errors occur, then this is most likely cause of drive failure. Perform a read of entire drive to determine if errors are electronic in nature, or physical in nature. Electronic problems will result in errors displayed not always being same type or in same location on drive. If problem is electronic, replace cable, controller, and finally drive electronics and repeat read test until no errors occur. If error is physical, use an INT 13 type editor (such as Norton Advanced Editor), to block entire drive and write information to a daisy chained drive set to same parameters as faulty drive.
The next step, after drive passes read test on first 10 cylinders, is to check original partition setup of drive.
Step Four: Check for physical location of master boot sector and volume boot sector.
In Micro-Scope, Utilities, Fixed Disk Editor - use FIND feature to search last two bytes of each cylinder for a boot signature (55 AA). The first location where a boot signature should be found would be at cylinder 0, head 0, sector 1 (the master boot sector). The second location where a boot signature should be found is at cylinder 0, head 1, sector 1 (the volume boot sector). It is also possible to use FIND feature to locate volume boot sector by searching for MSDOS (in DOS based systems) or MSWIN (in Windows95 systems).