Data Buzz

Physical Data Recovery from a CompactFlash Card

23 May 2018
Written by datapros. Posted in Data Recovery, Informative, Logical Data Recovery

CompactFlash (CF) is a flash memory electronic non-volatile computer storage medium that can be electrically erased and reprogrammed used mainly in portable electronic devices such as Canon and Nikon for their digital still cameras.

CompactFlash uses the Parallel ATA interface whereas CFast, by the same company uses the Serial ATA interface.

Technical details

The CompactFlash interface is a 50-pin subset of the 68-pin PCMCIA[14] connector. The card can be inserted into a passive 68-pin PCMCIA Type II to CF Type I adapter that fully meets PCMCIA electrical and mechanical interface specifications. The interface operates, depending on the state of a mode pin on power-up, as either a 16-bit PC Card (0x7FF address limit) or as an IDE (PATA) interface.

The CF device contains an ATA controller and appears to the host device as if it were a hard disk. CF cards with flash memory are able to cope with extremely rapid changes in temperature from −45°C to +85°C. There may be slight variations depending on the manufacturer of the CF, but for the most part there is a great range in temperature fluctuation which is perfect for the photography industy.

Limitations

– Battery life
– Number of erase/write cycles: NOR flash has a write endurance of 10,000 cycles and NAND flash 1,000,000 writes per block before hard failure
– Wear on blocks
– CF’s use a wear leveling process that varies the physical location to which a block is written
– NAND flash memory is prone to frequent soft read errors
– It does have error checking and correcting that detects the error and re-reads the block
– Lacks the mechanical write protection switch that other devices have
– Limited use due to its size

Items that can Prevent Data Recovery

– Accidental reformatting causing corruption
– Over shooting the card can corrupt images and may lead to card lockup
– Using the card in more than one camera without formatting each time can corrupt the card
– Deleting images in the camera can result in a back fill problem that computers are able to piece together, but can make data recovery difficult.
– ex: Picture 2 (new picture) 1.25MB deleted and new picture 2 (back filled) is 1.60MB in size
– Logical/software issue with being seen on the computer
– Removing the card from the camera when still recording images
– Not all cameras allow the card removal while still powered on
– Dirt and lint can ruin the cards if they’re not stored in their case
– Camera battery dies as images are recording can cause a card error

The basic concept behind flash file systems is the following: when the flash store is to be updated, the file system will write a new copy of the changed data to a fresh block, remap the file pointers, then erase the old block later when it has time. So as long as the file structure is not corrupt the images can be restored.

However, severe corruption can affect the raw files making them recoverable, but unreadable. There is still hope, but it is not an inexpensive option and that is to read off of the flash memory its self. This requires a clean lab and a few other high end tools.

Until next time from Data Buzz.

Metadata – Data About Data

23 May 2018
Written by datapros. Posted in Data Recovery, Informative, Logical Data Recovery

Meta what? Well simply put it is data about data. The main purpose of metadata is to facilitate in the discovery of relevant information also known as resource recovery.

Let’s use the library filing system as an analogy. Who’s the author, title, category, subject?

Well metadata is simply descriptive and structural data on your data.

Descriptive Metadata

Individual instances of data content of application data.

Structural Metadata

Think of the data structure as a container for the data. The style of the container requires specifications and then it needs to be designed.

Metadata also helps provide digital identification (location information) and organize electronic resources by relevant criteria and distinguishing similar and dissimilar resources.

So metadata is the data providing one more characteristics of the data. Location of where it stored, standards used, author, time and date, purpose and means of creation.

Until next time on Data Buzz.

What Is “Logical” Data Recovery?

23 May 2018
Written by datapros. Posted in Data Recovery, Informative, Logical Data Recovery

Logical data recovery is the repairing of “logical damage” on the storage media. This simply means the error is not a problem in the hardware and requires software-level solutions.

This explanation sounds so simple, but exercise caution if you are not computer literate or comfortable with attempting this on your own. Remember the old cliche “Go with your gut instincts?”

Logical damage can be caused by:

Corrupt file systems and partitions

Data on a hard drive can be unreadable due to damage to the file system or partition table. In the majority of these cases, at least a portion of the original data can be recovered by repairing the file system or the damaged partition table using specialized data recovery software. In some cases data can be recovered using relatively simple methods and tools; more serious cases can require expert intervention, particularly if parts of files are irrecoverable.

Media errors

Resulting from crashed heads and/or platter damage within the hard drive. This form of data recovery gets more expensive as it requires a clean lab environment to disassemble the damaged hard drive. Once repaired (temporary) the data can then be recovered to a new media source. This is known as a physical and a logical data recovery. Think of your car. The main computer crashes (physical) and is replaced with a new one, but still requires a flash of the software (logical) before the car will run as designed. If there is damage to the platters there is a method to recover the data called “File Carving”. This will be discussed at another time.

Overwritten data

There is no practical method for recovering data that has been overwritten.

Now if your hard drive is a Solid-State drive (SSD) recovering overwritten data is possible as these hard drives use flash memory to store data in pages and blocks.

Our next Data Buzz will discuss metadata, data about data, which will provide a bit more insight into how the structure of data can be recovered.

Until next time from Data Buzz.

Crash!!! – Not backing up can result in data loss at the worst time

23 May 2018
Written by datapros. Posted in Data Recovery, Informative, Logical Data Recovery

Yup. I said it. The dreaded hard drive crash. Been there done that.

Everyone backs up their data. False!!!

Let’s face it. There is never enough time in a day and unless you have hired someone to manage the data backup of your company or personal systems it’s not going to happen on a regular basis.

As time goes by it becomes easier and easier to put it off one more day, week, month…..

Who knows if and when your hard drive will crash? Sometimes there are signs and sometimes not. I wish this on no one, but we’re so busy with life that something has to be pushed to the back burner.

For some the loss of data is no big deal, but for others it can mean a loss of family photos, personal records, business records and so on.

Should your system crash and no longer boot up there are options.
– Format and install the operating system. There is the chance of losing some files.
– Replace the hard drive and install the operating system
– Call a friend

For those who must get their data back I recommend data recovery services. We use specialized hardware designed specifically for data recovery. There are software packages. Some work, some don’t, but this is another blog buzz for later.

I know the costs for data recovery can seem expensive, but you have to look at the value of the services. Retrieving priceless photos, personal or business records will make the costs seem negligible. Can you imagine losing one day of business records? So what happens come tax time? You see where I’m going. Look at the bigger picture.

Untill next time from Data Buzz

Why is my hard drive not booting?

23 May 2018
Written by datapros. Posted in Data Recovery, Informative, Logical Data Recovery

Hardware doesn’t last forever. A malfunction or complete failure occurs no matter how diligent one is at looking after one’s computer or server.

Physical Hard Drive Failure:

– the power delivery system
Should this fail during a booting or shutdown sequence or while your system is in use, can lead to file corruption. This is a good example of a physical and a logical failure.

– the circuit board
The system cannot read any data thus your system will not boot.

– the motor/bearings
No motor working the no spinning platters thus your system cannot boot. Bad bearings. Yikes!!! If you hear odd noises from the hard drive shut your system down and get your datatransferred and the hard drive replaced.

– the drive heads
They move above the platters converting magnetic field into electric current which is the read process. The reverse is for write. If a head touches a platter it can mean catastrophicfailure.

Logical Hard Drive Failure:

– a simple invalid entry in a file allocation table
While the drive itself is good the files do not load up right or the meta-data describing where the files are stored is not consistent.

– loss of the file system on a severely fragmented drive
So think of the hard drive as a book with a missing page or pages. For a hard drive this could mean it is missing crucial data required to boot successfully.

– data on the drive is corrupt
Power outages or other power related problems can corrupt the data. Improper shutdowns, hardware problems such as bad memory, bad sectors and even hard drive failures contribute.

Until next time on Data Buzz.