Wednesday, July 30, 2008

Recovery of Data Dependencies

Today, many companies have to deal with problems in maintaining legacy database applications, which were developed on old database technology. These applications are getting harder and harder to maintain. Re-engineering is an important means to address the problems and to upgrade the applications to newer technology (Hainaut, Englebert, Henrard, Hick, J.M., & Roland, 1995). However, much of the design of legacy databases including data dependencies is buried in the transactions, which update the databases. They are not explicitly stated anywhere else. The recovery of data dependencies designed from transactions is essential to both the re-engineering of database applications and frequently encountered maintenance tasks. Without an automated approach, the recovery is difficult and time-consuming. This issue is important in data mining, which entails mining the relationships between data from program source codes. However, until recently, no such approach was proposed in the literature.

Recently, Hee Beng Kuan Tan proposed an approach based on program path patterns identified in transactions for the implementation of the most commonly used methods to enforce each common data dependency. The approach is feasible for automation to infer data dependencies designed from the identification of these patterns through program analysis (Muchnick & Jones, 1981; Wilhelm & Maurer, 1995).

Data dependencies play an important role in database design (Maiser, 1986; Piatetsky-Shapiro & Frawley, 1991). Many legacy database applications were developed on old generation database management systems and conventional file systems. As a result, most of the data dependencies in legacy databases are not enforced in the database management systems. As such, they are not explicitly defined in database schema and are enforced in the transactions, which update the databases. Finding out the data dependencies designed manually during the maintenance and re-engineering of database applications is very difficult and time-consuming. In software engineering, program analysis has long been developed and proven as a useful aid in many areas. This article reports the research on the use of program analysis for the recovery of common data dependencies, that is, functional dependencies, key constraints, inclusion dependencies, referential constraints, and sum dependencies, designed in a database from the behavior of transactions.

For more information on Data Recovery, visit my Data Recovery Guide here.

The Best Way to Back Up Data Files

People usually store important files on their local hard drives, files that they cannot afford to lose.
A computer is a great machine, no doubt, but as any technical device, they can break. Some times your computer might not be responding correctly, and even though you think you have saved your files, they are gone the next time you boot your PC. This happens to a lot of people every day. Luckily, there are ways to make sure we do not lose our precious data.

There are many ways to back up your data. Floppy discs, CDs, DVDs, external hard drives, the internet - the list goes on. But what storage device is the most secure one?

CDs, DVDs and other discs can all break pretty easily. Spill a drink on them and you might not see your files ever again. Things like these can happen to most storage devices, the physical ones at least.

The safest and most secure storage device is most likely the internet. A website made for remote backups. These websites are operated by professional people who know what they are doing, and no matter what happens in your home or office, the internet never breaks. It will be right there waiting for you with your files when you need them again.
So my advice to anyone who needs a place to store their data backups; Find a nice and secure website managed by experts. In this way, your data is avaliable any time, any where - safety guaranteed.

To learn more about the different types of data recovery and backup, visit

Data Backup - Local Backup Vs Online Backup

My interest and expertise in backup solutions started when my hard drive crushed and died. On that drive I had all my business files %2B all my family photos. I couldn't stand the thought of loosing all this, so I found a data restore company, they gave me a good service which cost me almost $2000. After my recovery I understood how underestimated is the data on our computers and I decided to help all my family, friends and clients to become "Data Loss Protected."

When I decided to check out my backup options, I learnt that there are several options, and each option has some specific techniques that everyone should know about for creating a successful backup.

First Option -- Local Backup

Local backup is every type of backup that will keep your backup data on physical media available close to you. This can be:

  1. Additional internal hard drive.
  2. External hard drive
  4. Magnetic Type media
  5. Local Network backup
Local Backup Advantages: These types of backup are:

  1. Very handy, and until lately it was the simplest to do.
  2. It psychologically feels safe to have your original as well as backup in your physical possession.
Today, I will suggest anyone who backs up his data using this option to think about it as a partial solution at best. I use this option, I am backing up my main PC data to my laptop every day and I also back up once a week to an external hard drive, but all this is only my SECONDARY backup solution.

Local Backup Disadvantages: On the other hand, the system suffers from certain flaws.

  1. All these types of backup will not protect your data completely. Some very dangerous threats still exist:
    • Theft
    • Fire
    • Natural disasters like earthquakes, floods and more
    • Manmade disasters like terrorists attacks, war
  1. It is mostly NOT a fully automatic backup. It depends on many human behavioral activities in order to be thorough and updated.
Second (Better) Option -- Online Backup also known as Remote Backup

This is in my opinion the best solution; it covers all the disasters can happen

Online Backup Advantages:

  1. Automatic -- Most systems will require just a short setup, and from that moment on they will be fully automatic.
  2. Resides in a safe place -- the same as keeping your money in the bank, away from home. It is better to keep your data in a safe place and not at home or at your office, where it is likely to suffer from the same physical calamity that may befall your main storage system.
  3. Unlimited storage -- Some of the systems will enable you to backup unlimited data, and this gives you peace of mind.
Online Backup Disadvantages: This short answer is: None.

The longer answer might include the psychological issue that many people still feel that if their data is somewhere out there it is less safe than near them. The truth, believe me, is exactly the opposite. This streak of distrust in others would have to be overcome.

Daniel Shalgi-Shira is a backup expert.

He wrote this excellent backup step by step e-course.

You can get this e-course now for free. His website is full of backup and online backup information.

Impact of Computer Disasters

Computer disasters for people in the computer world can be quite different and yet can have the same mind numbing effects as a real world disaster. When someone suddenly losses data without any warning they begin to panic. Don't worry, because data recovery is possible and even though you may think that everything is lost there is a good chance that it can be recovered with the right data recovery software.

The damage that happens to a home because of a natural disaster can result in a complete mess. Most people will feel ruined because of the tremendous equipment casualty that can be done to a home. Once we know that there is no harm to any humans or pets in a building or office building, the disaster data recovery is ready to begin. Computer technicians with data recovery experience are called in to begin work on your computer equipment or any other piece of equipment that was damaged by the unfortunate disaster.

Data backup and recovery is always very necessary. Most of the ways that professional data recovery technicians use to recover lost files from hard drives that have been physically damaged are the same techniques used to recover lost data, files, or information from other technology, for instance retrieving lost files from a physically damaged hard drive is very similar to finding lost data from a hard drive with a virus.

Companies or individuals that have lost important data to a flood, fire, or earthquake face a time of doubt that is unrivalled in the world of business conflicts and personal negativity. Data recovery technicians are specialized in multiple areas of recovering data including: fire recovery, water damage recovery, or any other miscellaneous crash recovery that may have happened. Disaster data recovery will always have a place in the records of office and/or personal lives and other computer users could not be more grateful.

How to Recover Data From Mobile Phones

Professionals increasingly carry data on their cell phones, including email messages, documents, videos and instant messages. Also now the financial transactions can be carried out via the mobile phone, this means that an individual can easily transfer the money from one account to another; pay the bills and much more. This information can belong to different levels of priority; i.e. from personal & confidential information to some very secret information about company deals, etc. This increases the risk of hackers who want to get at that data without your permission, to attack your mobile phone.

To extract data from a mobile phone was not an easy thing to do few years ago. However, with the advancement in the forensic science, many tools exist which help in extracting all the information from your mobile phone. Of course, there are some challenges that are faced during this process. The biggest one is that there are hundreds of models of cell phones, with manufacturers adding dozens of new ones each year. And all those models employ a wide array of BIOS versions, operating systems and software. The other nut to crack is portability.

Mobile forensic experts should always stress on the following as the main sources of evidence:

1. The subscriber,
2. The mobile station, and
3. The network

Some of the other sources for collecting evidence could be:

- Look for the SIM card which provides details regarding the name of network provider and a unique ID number printed on the surface.

- SIM contains a processor and non-volatile memory. So using a standard smart card reader and SIM access software like AgapeMobiTool, one can easily extract all the information from the mobile phone.

- Gather the contacts that are stored in the SIM. Also look out for the SMS sent and received, to get any clue.

- Check the Settings (language, date/time, tone/volume etc), stored audio recordings, images/multimedia files, executable programs (e.g. J2ME), stored calendar events, GPRS, WAP and Internet settings.

- Look out for the calls received and dialed. Even if someone deletes the entries, it can be found out as that memory location is filled with void. So issues related to evidence tampering can also be tracked.

Following these steps can help in recovering the data from mobile phones and hand held devices and can help in investigation.

For more information on forensics, visit:

400 GB of Data on a Single Blu-Ray Disc

400 GB of data on a single disc. Seems to be quite amusing for some while some would say that it will take time to achieve it. But Japanese electronics giant Pioneer has made it possible. Pioneer has developed world's first 16-layer blu-ray disc, squeezing 25 GB of data on each layer thus totaling to an amazing figure of 400GB.

The currently commercially available blu-ray discs have the storage capacity of 25 GB. Those having two layers can store 50 GB of data. The problem in developing multiple layers disc have been to obtain a clear and stable signal from each recording layer. The frequently visited problems were crosstalk from adjacent layers and transmission loss. Pioneer managed to overcome these issues and developed a disc structure that reduces crosstalk from adjacent layers. Finally it came with a 16-layer optical disc that can play back high-quality signals from each layer.

The good news is that these high capacity discs are backward-compatible and will play on blu-ray disc players. These discs can be read using the same objective lens in current Blu-ray drives. Video game publishers and movie studios can use these discs to take more content on a single disc.

With the development of this technology, Pioneer is putting a green spin on the development. Discs with such enormous capacities mean fewer resources are consumed to deliver the same data or movies on Blu-ray media. For consumers, the main advantage of this technology is the chances of renting an entire season of a television show or collection of movies on a single disc. No need of disc-swapping.

So what do you think? Isn't it the future of data storage?

If you are interested in the manufacturers, suppliers, and wholesalers list of data storage devices, click here.

Pattrick is working as an industry analyst in the electronics and electrical industry for last fifteen years. He is working on a blog where you can get a lot of information on electronics industry, news, innovations, tradeshows, etc.

Common Situations Leading to Unrecoverable Data

Attempted Home Recovery

The first major cause of permanent data loss is due to an attempted home repair that has failed. Unfortunately, many people do not realize that although a hard drive appears extremely stable from the outside, the inside of a drive is extremely sensitive to environmental changes. The hard metal case is there for a reason, it is to protect the inside storage medium. The actual platters inside a drive that store all of the data must maintain an equilibrium in which measurements are made in tiny fractions. A single movement can throw a platter permanently off its track and destroy data instantly. In addition, exposing a platter to the elements outside of a professional clean room environment can be catastrophic.

Opening a hard drive.

Always adhere to manufacturer's guidelines when dealing with a hard drive, there is a reason that most all manufacturers void your warranty if the hard drive is opened. Most data recovery companies are certified to open a hard drive without voiding the warranty, because they have agreed to follow important guidelines. Breach of a drive by a home user almost always leads to disaster, and should be avoided at all costs. There is also a reason that data recovery companies invest thousands of dollars in Class100 clean rooms. It is not a scam; it is a preventative measure since opening a hard drive should only be done as a last resort and in a controlled environment.

Data Recovery Software

Another common reason a drive is sent to a data recovery service is due to the failed usage of data recovery software on a drive. Unfortunately, many people do not realize that in the area of data recovery you really do get what you pay for. Inexpensive recovery software can be valuable in various small scale recovery operations, but can be disastrous in all other situations. Over 50% of hard drive failures are due to mechanical issues, and software will only make the problem worse. Some of the software even writes recovered data straight back onto the damaged hard drive, which is redundant to say the least.

Always use care to avoid these common mistakes when dealing with a damaged hard drive. Do not assume that the drive can first be thrown through a bunch of home remedies and recovery software programs, and then sent to a professional only as a last resort. Most of the time, the data has already been permanently destroyed and a data recovery company will not be able to help.

There are several common situations that data recovery companies run into when trying to restore a client's information from a hard drive. In extreme cases the data can become unrecoverable and unfortunately permanent data loss will result. The cases in which this phenomenon can occur commonly result from the usage of home remedies or improper care of the hard drive after it has experienced a failure.