Rabu, 25 Juni 2008

Data Recovery/Datenrettung & Securing Data on Computers

Data recovery is the process by which the data is recovered from damaged or inaccessible storage media. Data recovery is done from storage media like CD´s, DVD´s, Floppies, Hard disks, Magnetic tapes etc. There are two reasons due to which the data becomes inaccessible. They are logical damage and physical damage to the storage media. Physical damage to storage media can occur in many ways. Magnetic tapes can break, get crumpled or dirt may settle on the tapes. CD´s and DVD´s can have scratches or the metallic layer may get damaged. Magnetic heads in hard disks can crash or motors may fail. The floppy is notorious for failing frequently due to bending, overheating, cold, dust etc. There are other reasons like fires, electrical surges etc that can cause data to become inaccessible or lost. There are many methods by which data can be recovered from magnetic media or optical media. The methods most commonly used are Magnetic Force Microscopy (MFM), Scanning Probe Microscopy (SPM), Magnetic Force Scanning Tunneling Microscopy (STM) etc.

In these methods a sharp magnetic tip is placed closed to the surface to be analyzed. It interacts with the stray magnetic field. An image of the data is generated and then repairs are carried out on logical damage and thus the data is recovered. Many companies carry out data recovery. Logical damage is the damage to the file system. It is not physical but a software problem. It generally occurs due to power cuts, system crashes etc preventing file system structures from being written resulting in file system being left in an inconsistent state. Logical damage is more common than physical damage. This may cause strange behavior like infinitely recurring file directories, loss of data, system crashes, hard disks reporting negative space etc. The end result is that the operating system cannot mount the file system. Most operating systems come with repair facilities like, Linux has fcsk utility, Mac has disk utility and Windows has chkdisk facility. There are other specialized programs available which have better repair facilities than the operating systems. There are also other systems called journaling file systems like NTFS, EFS (used in Windows XP), ext3 and xfs which can be reverted back to their earlier consistent state. These file systems reduce the amount of data loss. Data back up is the best way to prevent loss of data. The simplest method is to keep data on drives on which the operating system is not loaded. The other method is to write data on magnetic tapes, CD's or DVD´s or have online backup. Backups are very important for databases. Data backup is of 3 types. Full backup means backing up all data. Incremental backup means backing up of only the files that have changed. Differential backup is a mixture of these two. There is another method called continuous data protection in which when data is written to a disk, it is also written to another computer in a network.

Read more...>>>
Your Ad Here

How To Protect Your Hard Disk Drive Against Electrostatic Shock

If you've ever walked across a thick carpet and felt a shock after touching a grounded object (or shocked a friend on purpose) you know about the general effects of static electricity. But do you know how it works, or how damaging it can be to computer components? Although it may seem a bit silly and unimportant, "static shock" or Electrostatic Discharge (ESD) can cause significant damage to your hard drive. Comparable to a lighting bolt damaging a tree, ESD can act like a bomb exploding in your drive, blowing apart parts of the circuit board. But don't worry - if you follow a few simple steps you can ensure you're well protected and avoid letting a minor thing like ESD cause major problems.

WHAT IS ESD? ESD or "static shock" is a portion of an imbalanced high voltage field on a non-conductive surface (e.g. your hand, the carpet, a screwdriver) that has just moved to a conductive surface in a rapid, uncontrolled fashion. "Static electricity" is the same portion of an imbalanced high voltage field on a nonconductive surface, but it has not yet reached the point of releasing it's electrons to equalize the imbalance between a conductor with a greater positive charge than itself. This imbalanced high voltage field will not "discharge" until conditions are right, that is until the number of electrons the charge grabs from around its location builds to a point in which no more electrons can be sustained. When a conductive surface of some type gets within 'jumping" distance, the process of equalising the electrical field is experienced. Imbalanced high voltage fields are everywhere, constantly flowing over and around us, and people feel them because we are good conductors. The shock you sometimes get when touching a door knob after shuffling across the carpet is made in the same way a thunderstorm makes a lightning bolt. Some Examples of Voltage: • 3,000 volts - the average human can't feel voltage below this threshold. • 8,000 volts - yawning and stretching with clothes on. • 15-20,000 volts - shoving a plastic-coated box across the carpet with foot. • 18,000 volts - getting up from a foam cushion on a nylon-covered couch. • 35,000 volts - walking across a typical carpet.5 WHAT CAN ESD DO? While ESD won't kill you, it can definitely kill your computer components. While it takes an electrostatic discharge of 3,000 volts for you to feel a shock, much smaller charges, well below the threshold of human sensation, can and often do damage semiconductor devices. Many of the more sophisticated electronic components can be damaged by charges as low as 10 volts. ESD damage occurs when a charge on a hand or tool finds a path of lesser resistance from itself to a drive. If the energy of that charge is larger than the amount of energy the drive can safely dissipate, damage may occur. Especially sensitive to ESD are integrated circuits: processors, memory, cache chips and expansion cards. This damage can be immediate, resulting in melting, junction breakdown or oxidation. Even scarier, you could electrocute your drive and never even know it - the effects of ESD are difficult to trace and often do not affect the drive until several days to several months after the ESD occurrence. PREVENTION TIPS Luckily, a few simple steps can help you avoid ESD damage and promote long life for your disk drive. • Keep your drive in an ESD bag until you handle it - an ESD bag is specially designed to prevent ESD. • Always wear an ESD wrist strap grounded to an unpainted surface on the chassis of your computer. • If a wrist strap is unavailable, touch an unpainted surface on the chassis of your computer before handling your drive. • Only touch the connector pins on your drive with the proper cabling ends or jumpers. Never use a bare finger or non-insulated tool. • Protect your drive from sources of high voltage power such as fans or vacuum cleaners. • Never try to plug a power or data cable into a drive unless power to the box is completely off. Finally, by controlling the temperature, you can also help limit ESD. By increasing the relative humidity of the room where the computer is located, you can greatly reduce build-up of ESD. Static builds up more readily in dry environments than in moist ones; this is why you get zapped much more often in the winter time in northern climates than in summer. So what happens if by some freak accident your hard drive experiences ESD and your data is lost? Don't panic, because your best solution is only a phone call away. Many 'Data Recovery' companies have experience dealing with hard drives damaged by ESD and will apply the most advanced technology in the industry to perform data recovery. Contacting these immediately upon discovering ESD damage is the best option to keep you and your clients working and productive. Knowing that ESD exists is the first step in prevention. By following ESD handling procedures and understanding the dynamics behind "static electricity," you can ensure that working with a hard drive is never a shocking experience.

Read more...>>>
Your Ad Here

© 2008 Tape Data Recovery |  Kisstya Corner by Blogspot tutorial