Trouble-shooting Hard Drive Problems - Part 2

Written by Micro 2000 Inc

The following article isrepparttar second in a series that helps solve many ofrepparttar 137274 common boot problems with hard drives. (To readrepparttar 137275 first in article inrepparttar 137276 series click here).

The article explains how to reconstructrepparttar 137277 Volume Boot Record and will touch briefly on multiple-partition drives. 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 using a FAT 16 structure (all DOS and older Windows systems, some Windows NT), and no drive overlay.

A common problem with hard drives isrepparttar 137278 error message "MISSING OPERATING SYSTEM."

Typically what this means is that critical data is missing or damaged in two possible locations. The first isrepparttar 137279 Master Boot Record (MBR). This data area contains error messages and pointer information that specifiesrepparttar 137280 location ofrepparttar 137281 second critical data area,repparttar 137282 Volume Boot Record (VBR). The VBR containsrepparttar 137283 operating system specific data forrepparttar 137284 format of that particular partition onrepparttar 137285 drive. If either of these two critical data areas is damaged, by a virus, controller failure, etc., thenrepparttar 137286 drive will not be accessible throughrepparttar 137287 operating system.

The normal response to this error message is to boot to a floppy disk and to re-partitionrepparttar 137288 drive (probably using FDISK) and thereby totally removing any possibility for recovery ofrepparttar 137289 data on that drive, except by dedicated data recovery software or a data recovery facility. If applicable,repparttar 137290 following technique will help save time, money, and frustration.

The first step to data recovery (covered in great detail inrepparttar 137291 first article of this series) is to verifyrepparttar 137292 location ofrepparttar 137293 existing partition information. Forrepparttar 137294 purposes of this article, it will be assumed thatrepparttar 137295 FAT structure andrepparttar 137296 root directory are intact, there is only one partition, and that onlyrepparttar 137297 MBR andrepparttar 137298 VBR were damaged. Using Micro-Scope, enterrepparttar 137299 Fixed Disk Editor menu and selectrepparttar 137300 fixed disk that is being repaired. Usingrepparttar 137301 Find menu option, locate allrepparttar 137302 sectors that containrepparttar 137303 string "55 AA" (see Step Four ofrepparttar 137304 first article in this series), and then verify thatrepparttar 137305 FAT structures are intact (see Step Seven). Note on a scratch paperrepparttar 137306 values (in Cylinder, Head, Sector format) where this string appears. These values will be used later inrepparttar 137307 reconstruction process.

Rebuildingrepparttar 137308 MBR

Usingrepparttar 137309 Fixed Disk Editor in Micro-Scope, locate and read Cylinder 0, Head 0, Sector 1. This should berepparttar 137310 location ofrepparttar 137311 corrupt Master Boot Record. Press "M" to modifyrepparttar 137312 sector and enter 0's forrepparttar 137313 entire sector, effectively wiping allrepparttar 137314 data from this sector. Press ESC, then "W" to writerepparttar 137315 data, and "Y" to confirmrepparttar 137316 write operation. Then exitrepparttar 137317 Fixed Disk Editor and selectrepparttar 137318 Rebuild Master Boot Record menu option. Press "Y" to confirm this operation. The fixed drive now has a completely corruption-free MBR available for use duringrepparttar 137319 reconstruction ofrepparttar 137320 VBR.

Rebuildingrepparttar 137321 VBR

There is a simple method for rebuildingrepparttar 137322 VBR. Copyrepparttar 137323 data from a like fixed disk or a similar-sized fixed disk withrepparttar 137324 identical operating system (the versions must berepparttar 137325 same.) There are two approaches for obtaining this data. The first is to installrepparttar 137326 second drive inrepparttar 137327 system, reboot Micro-Scope, and copyrepparttar 137328 sectors directly fromrepparttar 137329 "healthy" drive torepparttar 137330 drive being reconstructed. The second method is to copyrepparttar 137331 sectors fromrepparttar 137332 "healthy" drive to a floppy diskette and transfer that diskette torepparttar 137333 machine containingrepparttar 137334 drive being reconstructed. The data can be copied to any sector onrepparttar 137335 floppy disk. Just note where this data is stored onrepparttar 137336 floppy disk so that it may be easily retrieved when copying it back torepparttar 137337 drive being reconstructed. In either case,repparttar 137338 VBR is located at Cylinder 0, Head 1, Sector 1 onrepparttar 137339 "healthy" drive. Copy this data torepparttar 137340 same location onrepparttar 137341 damaged drive. Exitrepparttar 137342 Fixed Disk Editor.

Trouble-shooting Hard Drive Problems - Part 1

Written by Micro 2000 Inc

The following article isrepparttar first in a series that helps solve many ofrepparttar 137273 common boot problems with hard drives. The article explains how to verifyrepparttar 137274 drive functionality, determinerepparttar 137275 correct setup forrepparttar 137276 drive, and repair problems withrepparttar 137277 Master Boot Sector oncerepparttar 137278 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 onrepparttar 137279 hard drive without first verifyingrepparttar 137280 hard drive configuration. Therefore,repparttar 137281 first priority when unable to access information on a hard drive is to verify all ofrepparttar 137282 configuration information dealing withrepparttar 137283 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 detectsrepparttar 137284 hard drive

In Micro-Scope, System Configuration, Compare Settings - check to make sure that there is not an asterisk besiderepparttar 137285 number of hard drives detected value. If there is an asterisk, eitherrepparttar 137286 CMOS is set incorrectly, or there is an electronic problem (controller, cable, drive).

Step Two: Comparerepparttar 137287 BIOS parameters againstrepparttar 137288 drive partition information.

In Micro-Scope, System Configuration, System Information - noterepparttar 137289 information displayed forrepparttar 137290 hard drive, specificallyrepparttar 137291 parameters forrepparttar 137292 drive in question. Compare these parameters torepparttar 137293 parameters inrepparttar 137294 MBR display under Micro-Scope, System Configuration, Partition Display usingrepparttar 137295 following formula:

System Information Master Boot Record Cylinders Ending Cylinder + 2 Heads Ending Head + 1 Sectors Sectors Per Track

Ifrepparttar 137296 information does not match, eitherrepparttar 137297 partition information is corrupt, orrepparttar 137298 CMOS setup or controller BIOS setup (if one exists) is incorrect, or there is a problem communicating withrepparttar 137299 drive.

Step Three: Checkrepparttar 137300 drive functionality

In Micro-Scope, Diagnostics, Fixed Disk Tests - checkrepparttar 137301 information inrepparttar 137302 Fixed Disk Selected window. Make sure thatrepparttar 137303 proper drive type, model, and native parameters are showing in this window. If any ofrepparttar 137304 information is incorrect, there is an electronic problem. Checkrepparttar 137305 cable, controller and drive, re-seating all connections, and repeatrepparttar 137306 above procedure. After correctingrepparttar 137307 electronic problem, perform a read test onrepparttar 137308 first 10 cylinders ofrepparttar 137309 drive. If any errors occur, then this isrepparttar 137310 most likely cause ofrepparttar 137311 drive failure. Perform a read ofrepparttar 137312 entire drive to determine ifrepparttar 137313 errors are electronic in nature, or physical in nature. Electronic problems will result inrepparttar 137314 errors displayed not always beingrepparttar 137315 same type or inrepparttar 137316 same location onrepparttar 137317 drive. Ifrepparttar 137318 problem is electronic, replacerepparttar 137319 cable, controller, and finally drive electronics and repeatrepparttar 137320 read test until no errors occur. Ifrepparttar 137321 error is physical, use an INT 13 type editor (such as Norton Advanced Editor), to blockrepparttar 137322 entire drive and writerepparttar 137323 information to a daisy chained drive set torepparttar 137324 same parameters asrepparttar 137325 faulty drive.

The next step, afterrepparttar 137326 drive passesrepparttar 137327 read test onrepparttar 137328 first 10 cylinders, is to checkrepparttar 137329 original partition setup ofrepparttar 137330 drive.

Step Four: Check forrepparttar 137331 physical location ofrepparttar 137332 master boot sector andrepparttar 137333 volume boot sector.

In Micro-Scope, Utilities, Fixed Disk Editor - userepparttar 137334 FIND feature to searchrepparttar 137335 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 userepparttar 137336 FIND feature to locaterepparttar 137337 volume boot sector by searching for MSDOS (in DOS based systems) or MSWIN (in Windows95 systems).

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