Backups and Hard Disk Recovery

How to Backup your Hard Disk Data:

The data stored on your hard drive is the most critical part of your computer, which cannot be easily replaced. It may be an unwanted expense to repair and replace defective memory, monitor, or a processor, but there is no easy way to replace years of your critical data!
Inside view of a Hard Drive
Inside view of Hard Drive (covers removed)
In addition to the possibility of a simple (mechanical) hard drive failure, the threat of Internet borne worms and viruses has become an increasing risk to data loss or corruption. Although you may not be able to provide absolute protection to your hard drive, there are various ways that you can ensure that the data on your hard drive is archived. Three methods of backing up your data are summarized below:

1. CD and DVD Writers:

The falling prices of CD and DVD burners have made them a ‘essential’ part of just about every modern computer. These devices can typically be found installed in a computer case, but external devices supporting USB 2.0 or Firewire interface are available for greater flexibility, mobility and ease of installation.
The main limitation of using a CD writer for data backups is that the discs are generally limited to a capacity of 700MB per disc. Not nearly enough for a full backup, but adequate for archiving key files.
DVD media offers the user far more storage capacity than a CD, and most modern DVD burners can burn CDs as wells as DVD's. The recent availability of dual layer DVD burners represents a large boost in the capacity of writable DVD's, taking the previous limit of 4.7GB per disc and nearly doubling it to 8.5GB.
With proper storage, CD/DVD media can provide long-term storage (life expectancy is about 40 years) that cannot be jeopardized by hardware failure. Most computers can easily read the data on a CD or DVD.

2. External Hard Drives:

External hard drives are typically the same type of drive you might find inside your system, but housed in a smaller, external enclosure of its own. The enclosure will feature at least one data interface (such as Firewire or USB), and the capacity is only limited by the size of hard drives presently available and the user’s budget.
The capacity of external hard drives makes them ideal for backing up large volumes of data, and many of these devices simplify the process by including software (or hardware) features to automate the backup.

3. Additional Hard Drives (and RAID):

By adding an additional hard drive to you system, you can protect yourself from data loss by copying your data from your primary drive to your secondary drive. The installation of a second hard drive is not’t difficult, but does require a basic understanding of the inner working of a computer.
To take the installation of a second hard drive to another level of security and reliability, the hard drives may be installed in a RAID array. RAID stands for a Redundant Array of Independent Disks, and can be configured in several manners. A RAID 1 array requires two hard drives of equal size to be installed on a RAID controller, which will then mirror one drive to the other in real time. Many motherboard's now come with RAID controllers onboard. With a RAID 1 array in place, if one hard drive should ever fail, the system won’t miss a best by continuing to run on the remaining good drive, and alert the user that one drive may need to be replaced.

4. Create your own Backup System:

For those than already have or can afford an external hard drive, I highly recommend you read through this simple method of implementing your own backup

Hard Disk recovery and Rescue:

Hard Disk Rescue
Common causes & symptoms of Data loss in Hard Disk Drives (HDD)
Symptoms
Possible causes & recovery cases
Hard drive crash.
Inaccessible drive and partitions
Computer won't boot
Hard drive failed.
Dead HDD. No spinning sound. ·  Power surge, burned elements on PCB (Printed Circuit Board)
·  Stuck motor, stuck heads
·  Mechanical failure, internal parts damage
Drive spins with normal sound, no clicking.
The name of the drive could not be recognized by computer BIOS/CMOS.
Damaged HDD Firmware microcode
Clicking Hard Drive
Mechanical failure, internal parts damaged (esp. heads)
Normal spinning sound, drive can be recognized by computer BIOS/CMOS Applications are unable to run or load data.
Corrupt files/data, bad sectors.
Virus attack.
Accidental reformatting of partitions.
Accidentally deleted files.
Normally, Software recovery is available for those symptoms.
Applications are unable to run or load data. Corrupt files data, bad sectors
Software recovery attempts fail =
(dangerous!)
Damaged magnetic layer on the spinning platters (disks) is heavily damaged; Software recovery cannot be performed directly on the damaged drive.
Inaccessible drive and partitions. Possible corrupted partition table data  and / or master boot sector. Software recovery needed.
Peter Bowey Computer Solutions has a range of low-level software hard disk recovery tools (workshop service only) to recover and repair data in most cases; - where mechanical failure has not impacted the physical operation of your hard drive!

Why Hard Drives do fail!

Modern Hard Drives have a hermetically sealed enclosure that protects the drive internals from dust, condensation, and other outside sources of contamination. The hard disk's read-write heads fly on an air bearing which is a very thin cushion of air only nanometers above the disk surface. The disk surface and the drive's internal environment must therefore be kept immaculate to prevent damage from fingerprints, hair, dust, smoke particles, etc., given the submicroscopic gap between the heads and disk.

Looking inside a Hard Drive:

The hard drive enclosure relies on air pressure inside the drive to support the heads at their proper flying height while the disk is in motion. A hard disk drive requires a certain range of air pressures in order to operate properly. The connection to the external environment and pressure occur through a small hole in the enclosure (about 1/2 mm in diameter), usually with a carbon filter on the inside (the breather filter, see below). If the air pressure is too low, there will not be enough lift for the flying head, the head will not be at the proper height, and there is a risk of head crashes and data loss. Specially manufactured sealed and pressurized drives are needed for reliable high-altitude operation, above about 10,000 feet (3,000 meters). This does not apply to pressurized enclosures, like an airplane pressurized cabin. Modern drives include temperature sensors and adjust their operation to the operating environment.
Inside a Hard Disk
Close-up of a hard disk head suspended above the disk platter together with its mirror image in the smooth surface of the magnetic platter. Very high humidity for extended periods can cause accelerated wear of the drive's heads and disks by corrosion. If the drive uses "Contact Start/Stop" (CSS) technology to park its heads on the disk when not operating, increased humidity can also lead to increased stiction (the tendency for the heads to stick to the disk surface). This can cause physical damage to the disk and spindle motor and can also lead to head crash. Breather holes can be seen on all drives — they usually have a warning sticker next to them, informing the user not to cover the holes. The air inside the operating drive is constantly moving too, being swept in motion by friction with the spinning disk platters. This air passes through an internal filter to remove any leftover contaminants from manufacture, any particles or chemicals that may have somehow entered the drive, and any particles or out-gassing generated internally in normal operation.

Hard Drive Head crashes:

Due to the extremely close spacing between the heads and the disk surface, any contamination of the read-write heads or disk platters can lead to a head crash — a failure of the disk in which the head scrapes across the platter surface, often grinding away the thin magnetic film. For giant magneto-resistive heads in particular, a minor head crash from contamination (that does not remove the magnetic surface of the disk) will still result in the head temporarily overheating, due to friction with the disk surface, and can render the data unreadable for a short period until the head temperature stabilizes (so called "thermal asperity", a problem which can partially be dealt with by proper electronic filtering of the read signal). Head crashes can be caused by electronic failure, a sudden power failure, physical shock, wear and tear, corrosion, or poorly manufactured disks and heads.
Information