Data Recovery

What is a Data Loss?

	Data has accidentally been erased or data control structures have been overwritten
	Data has been corrupted or made inaccessible.
	Data is unable to be accessed from a previous functioning computer system or backup

Things to Know About Data Loss

Data loss is disastrous at home, but for companies it causes setbacks in time and money.

If the data loss recovery is dealt with quickly or the necessary precautions are taken prior to any problem, the company could retrieve the data more easily or not experience a problem at all

Generic Problems

	Computer won’t boot up
	Applications that are unable to run or load data
	Hard drive crashes
	Corrupt files or data
	Accidental reformatting of partitions
	Inaccessible drives and partitions
	Media surface contamination and damage

What causes Data Loss?

	Sabotage
	Natural Disaster
	Hardware Error
	Virus Attack
	Human Error 1. Intentional deletion 2. Accidental overwriting of files
	Software Corruption

How to Prevent Data Loss

	Don’t upgrade hardware or software without having a backup
	Physically secure your system from intruders
	Use firewalls and virus protection
	Be prepared for physical disasters

Data Recovery

	The majority of data loss situations are recoverable
	Computer storage systems may fail, but the data stored on them is not always completely lost.
	There are occasions when damage to data is permanent and complete data recovery is not possible. However, some data is usually always recoverable.
	Data recovery professionals can recover data from crashed hard drives, operating systems, storage devices, servers, desktops, and laptops using various proprietary data recovery tools and techniques.

Data Recovery Tips

Do’s

	Backup your data frequently.
	If you believe there is something wrong with your computer shut it down, do not continue to power up because you may do more damage.
	If you here a clunk, clunk sound when you power up the drive, shut down! Do not panic nor turn the power button on and off.
	Package the drive properly when you send it in to a data recovery specialist. You can cause additional damage to the hard drive if it is poorly packaged.

DON’TS

	Do not ever assume that data recovery is impossible; even in the worst cases, such as natural disasters data recovery specialists have been able to retrieve valuable data.
	Never remove the cover from the hard drive; this will only cause further damage.
	Do not rest your computer on a moveable object or piece of furniture. Shock and vibration can result in serious damage to the hard drive.
	Do not subject the drive to extreme temperatures changes both hot and cold.
	In the case where a drive has been exposed to water, fire or even smoke do not try to power up.

How to Recover data

	Use of software to recover data
	Use of machines to recover data

Software Data Extraction

	Data extraction is the process of moving data off of the imaged drive to another destination location.
	Data extraction software scans sectors of the hard drive and restructures the file system either in memory or another hard drive.
	The software can be used to copy the recoverable data to a destination location.

Software Recovery

	Data loss can occur because the hard drive may have problems accessing the data it contains at a software or logical level.
	By making a complete sector copy (an exact copy including all deleted information) of the hard drive, using a program such as Norton GHOST, most data recovery programs search for deleted MFT (Master File Table) entries to undelete files.
	If the MFT is corrupt or defective, this method will not work. Some data recovery programs will ignore the MFT and search all of the unallocated clusters to try to find and recover files.

Data Recovery

	The user may send a failed hard disk drive to a private data recovery company that offers secure and confidential data recovery.
	The data recovery company will carefully perform part replacement of the heads, spindle motor and base casting, the electronics board, etc. in a clean room environment.
	Part replacement has historically been successful for data recovery about 40%-60% of the time.
	Normal disk circuitry is set up so that both these values are read as ones, but using specialized circuitry it is possible to work out what previous “layers” contained.
	The recovery of at least one or two layers of overwritten data isn’t too hard to perform by reading the signal from the analog head electronics with a high-quality digital sampling oscilloscope, downloading the sampled waveform to a PC, and analyzing it in software to recover the previously recorded signal.

Data Recovery Techniques

Scanning Probe Microscopy (SPM)

	A technique that is used to image and measure surfaces at the atomic level.
	Scans an atomically sharp probe over a surface which produces a 3D image of the surface at the atomic scale.

Magnetic Force Microscopy (MFM)

	MFM (Magnetic Force Microscopy) is a new technique which images the spatial variation of magnetic forces on a sample surface.
	MFM is derived from scanning probe microscopy (SPM) and uses a sharp magnetic tip attached to a flexible cantilever for analysis.
	An image of the field at the surface is formed by moving the tip across the surface and measuring the force.
	Detectable old data will be present beside new data on the track which is usually ignored.
	Together with software, MFM can see past various kinds of data loss/removal.
	Each track contains an image of everything ever written to it, but each layer gets progressively smaller the earlier it was written.
	MFM looks at the minute sampling region to detect remnant magnetization at track edges.

Scanning Tunneling Microscopy (STM)

	STM (Scanning Tunneling Microscopy) is a more recent variation of MFM which uses a probe tip typically made by plating nickel onto a pre-patterned surface.
	The probe is scanned across the surface that is to be analyzed. STM measures a weak electrical current flowing between the tip and the sample. The image is then generated in the same way as MFM.