| It is extremely important not to make or write any | | | | virus has infected the hard drive in the system. The |
| changes to data on the hard drive without first | | | | Rebuild Master Boot feature of Micro-Scope will |
| verifying the hard drive configuration. Therefore, the | | | | eliminate any boot sector virus. Be sure to boot the |
| first priority when unable to access information on a | | | | system to the Micro-Scope diskette and immediately |
| hard drive is to verify all of the configuration | | | | do a cold reboot of the system after using the Rebuild |
| information dealing with the suspect hard drive.Partition | | | | Master Boot feature.If the volume boot sector is found |
| Parameter | | | | in a location other than cylinder 0, head 1, sector 1, |
| Value or EquationPartition Status | | | | count the actual number of sectors before the volume |
| BootableStarting Head | | | | boot sector, and compare that value to the value for |
| 1Starting Sector | | | | the sectors per track displayed in the partition table |
| 1Starting Cylinder | | | | described in step 2. If the values match, the most likely |
| 0Partition Type | | | | cause of the system failure is an incorrect CMOS |
| Bigdos (drives greater than 30 MB), otherwise DOS | | | | setup. In this case the CMOS needs to be reset to the |
| 12Ending Head | | | | values indicated by the partition table described in step |
| Total Number of Heads -1Ending Sector | | | | 2, remembering to use the formula described in step 2 |
| Sectors per Track displayed in Volume Boot | | | | when doing so. If the values do not match, set the |
| SectorEnding Cylinder | | | | CMOS Sectors Per track to the number of sectors |
| Number of Cylinders set in CMOS - 2Total # of | | | | counted before the volume boot sector and continue |
| Sectors | | | | to the next step.Step Five: Check the partition tables to |
| Number of Sectors displayed in Volume Boot | | | | make sure they are correctReboot the system to |
| SectorStart Absolute Sector | | | | Micro-Scope and go to System Configuration, Partition |
| Number of Sectors per Track in Volume Boot | | | | Tables. Check the information displayed in the master |
| SectorBoot Signature | | | | boot record to see if there is any obvious corruption |
| 55AAStep One: Make sure that Micro-Scope detects | | | | (that is, excessively large numbers, all partitions |
| the hard driveIn Micro-Scope, System Configuration, | | | | non-bootable, etc.) If there is no obvious corruption in |
| Compare Settings - check to make sure that there is | | | | the master boot record, then perform step 2 again. If |
| not an asterisk beside the number of hard drives | | | | the information matches at this point, go to step 6. If |
| detected value. If there is an asterisk, either the CMOS | | | | the information does not match, then set the sectors |
| is set incorrectly, or there is an electronic problem | | | | per track in the Master Boot Record to the number of |
| (controller, cable, drive).Step Two: Compare the BIOS | | | | sectors per track currently set in CMOS, set the |
| parameters against the drive partition information.In | | | | starting head to 1, starting sector to 1, and starting |
| Micro-Scope, System Configuration, System | | | | cylinder to 0, and write the information to the drive.Step |
| Information - note the information displayed for the | | | | Six: Verify the Master Boot Sector informationDisplay |
| hard drive, specifically the parameters for the drive in | | | | the Volume Boot Sector and use the values for heads |
| question. Compare these parameters to the | | | | and sectors per track (on the right half of the screen) |
| parameters in the MBR display under Micro-Scope, | | | | to perform step 2 again.If the values match, then the |
| System Configuration, Partition Display using the | | | | volume boot sector is probably okay. If any values in |
| following formula:System Information | | | | the Master Boot Record do not match the table to the |
| Master Boot RecordCylinders | | | | right, reset the values to match the values in the table, |
| Ending Cylinder + 2Heads | | | | and write to the drive.If the values still do not match, |
| Ending Head + 1Sectors | | | | both the Master Boot Record and the Volume Boot |
| Sectors Per TrackIf the information does not match, | | | | Record are probably corrupt. At this point, e-mail |
| either the partition information is corrupt, or the CMOS | | | | Technical Support for help in this situation. Future |
| setup or controller BIOS setup (if one exists) is | | | | articles will provide more insight into the repair |
| incorrect, or there is a problem communicating with the | | | | procedure.Step Seven: Check the FATsCheck to see |
| drive.Step Three: Check the drive functionalityIn | | | | if the first FAT starts on the sector just beyond the |
| Micro-Scope, Diagnostics, Fixed Disk Tests - check the | | | | volume boot sector. Use the find feature in the Fixed |
| information in the Fixed Disk Selected window. Make | | | | Disk Editor to search for F8 FF FF in the first three |
| sure that the proper drive type, model, and native | | | | bytes of each sector. The first occurrence should be |
| parameters are showing in this window. If any of the | | | | on sector two of head one. Continue to search until |
| information is incorrect, there is an electronic problem. | | | | the second FAT is found, indicated by the second |
| Check the cable, controller and drive, re-seating all | | | | occurrence of F8 FF FF. Note the location of the |
| connections, and repeat the above procedure. After | | | | cylinder, head and sector of the second FAT.Based on |
| correcting the electronic problem, perform a read test | | | | the start of the second FAT, and the start of the first |
| on the first 10 cylinders of the drive. If any errors occur, | | | | FAT, calculate how many sectors are in the first FAT. |
| then this is the most likely cause of the drive failure. | | | | If necessary, read each sector starting at the first |
| Perform a read of the entire drive to determine if the | | | | sector of the first FAT, keeping a count of the sectors |
| errors are electronic in nature, or physical in nature. | | | | that have been read until F8 FF FF is seen in the upper |
| Electronic problems will result in the errors displayed | | | | left of the HEX display, which would indicate the start |
| not always being the same type or in the same | | | | of the second FAT. After calculating the sectors per |
| location on the drive. If the problem is electronic, | | | | FAT, compare this value to the value in the volume |
| replace the cable, controller, and finally drive electronics | | | | boot sector. If the values match, the drive should be |
| and repeat the read test until no errors occur. If the | | | | accessible through DOS at this point.Step Eight: |
| error is physical, use an INT 13 type editor (such as | | | | Attempt to access the driveBoot to a DOS-bootable |
| Norton Advanced Editor), to block the entire drive and | | | | floppy diskette and attempt to access the drive. If the |
| write the information to a daisy chained drive set to | | | | root directory and sub-directories on the hard drive are |
| the same parameters as the faulty drive.The next | | | | readable at this point, then attempt to boot to the drive. |
| step, after the drive passes the read test on the first | | | | If the drive boots at this point, the problem has been |
| 10 cylinders, is to check the original partition setup of | | | | corrected. If the drive is still not bootable, e-mail the |
| the drive.Step Four: Check for the physical location of | | | | Micro 2000 Technical Support department for |
| the master boot sector and the volume boot sector.In | | | | help.Disclaimer - The Micro 2000 Tech Tip is a free |
| Micro-Scope, Utilities, Fixed Disk Editor - use the FIND | | | | service providing information only. While we use |
| feature to search the last two bytes of each cylinder | | | | reasonable care to see that this information is correct, |
| for a boot signature (55 AA). The first location where | | | | we do not guarantee it for accuracy, completeness or |
| a boot signature should be found would be at cylinder | | | | fitness for a particular purpose. Micro 2000, Inc. shall |
| 0, head 0, sector 1 (the master boot sector). The | | | | not be liable for damages of any kind in connection |
| second location where a boot signature should be | | | | with the use or misuse of this information.Micro 2000 |
| found is at cylinder 0, head 1, sector 1 (the volume boot | | | | Inc has been helping to solve the day-to-day |
| sector). It is also possible to use the FIND feature to | | | | challenges that IT departments face in order to keep |
| locate the volume boot sector by searching for | | | | their businesses operational as well as profitable for |
| MSDOS (in DOS based systems) or MSWIN (in | | | | over 14 years. The company's primary goal is to put |
| Windows95 systems).If there is a duplicate copy of | | | | the customer first - through feature-rich, simple-to-use |
| the master boot sector found before the location of | | | | IT tools that can help IT administrators manage their |
| the volume boot sector, then it is possible that a boot | | | | jobs more effectively. |