General Introduction



Everyone who uses a computer should know that a fundamental technique to ensure no important data is lost is to constantly reliably back up your data. Even at today's super fast, highest tech level of computer design hard drives still fail.

Hard drives are a true feat of technology, engineered to spin at around 7200rpm, any physical encounter with even a small object that is not part of the machinery can cause huge amounts of damage. Such potentially disastrous occurrences are less likely nowadays since a variety of fail safe mechanisms are typically built in to hard drives to prevent physical damage.

When areas of a hard disk fail the whole hard drive tends to become useless. Specialists are then usually called in to try to retrieve as much data as possible. Routine back ups of your computers data make the retrieval process relatively easy and straightforward. All that is required is to re-install all the data. If no (or recent!) back ups of the data exist in the first place then you're in a very bad position, you have a limited range of data recovery procedures you can try before needing to call out expensive data recovery experts.

In terms of procedures you can try, hard drives are partitioned so that several drives can be seen on the computer. Sometimes only one of a number of partitions on a physical drive can fail. In this case everything is not usually lost, most likely recoverable with some effort. This is not always realized, a lot of people give up and buy a new drive, in the process loosing all their recoverable data.

Damaging hard drive sounds like loud clicks, scratching sounds and rattling should prompt you to immediately back up all your data and then buy a new hard drive.

When trying to understand how hard drives function to store data, the status of file systems partitions can be observed through running the Computer Management application which comes as part of Windows XP. Simply right mouse click on 'My Computer', then press on 'Manage' and lastly 'Disk Management'.

All hard drives operate a particular File System. File Systems are a method whereby the installed operating system is able to organize data and free space so that it can be easily read from and written to. Many partitions can be created from each physical disk, each one appearing as a separate drive e.g. C:, D: etc. The two main partition methods used with Windows Operating Systems are mentioned here, FAT16/32 and NTFS.

The most common partition type at the moment, NTFS (NT File System) is utilized by Windows NT/ XP. FAT-32 is operated by Windows 98 and onwards, FAT-16 had in the past been used by DOS/3.1/95. Modern operating systems are backwards compatible with older file systems able to read/ write to secondary disks centering on the older file system.

On both file systems the way in which the data is stored is organized by a Master Boot Record (MBR) and a Partition Table. Found in the first sector of the drive, both the MBR and Partition Table decide the organizational structure of the disk and from which partition to boot from.

CHKDSK

Often, so called 'disk failure' is through the corruption of the MBR or Partition Table that leads to a non-booting drive.

Tools in Windows can be used to try to solve this problem, namely the simple and easy to use SCANDISK (used on DOS/3.1/95/98/ME) and CHKDSK (used on NT/XP). Typically run from the Windows Installation CD or a bootable floppy disk, these applications should, unless you can identify the problem, be your first move towards a solution.

CHKDSK is able to locate and fix the majority of simple MBR problems, if run straight from a boot disk. In instances where your secondary hard drive has failed and booting directly to Windows XP is still possible, run 'CHKDSK/F' from the run command. What normally happens is Windows tries to remove such problems without the need for the user to manually run CHKDSK.

When unable to boot into Windows XP the CHKDSK file on another computer should be copied to, and run from, a bootable floppy disk. CHKDSK is also able to be run via the recovery console from the Windows XP boot CD.