Wedding photo’s lost, professional photographer

August 7th, 2010

A professional photographer with many weddings dropped his external hard drive, which was a Seagate 1TB, obviously he was extremely concerned, as was the bride and groom whom also had potentially ‘lost’ their precious day from that days shoot.

Upon receiving the faulty hard disk it was diagnosed with spindle seizure and HSA damage, both of which are serious failures the recovery would be very complex and would require many hours clean room work and other engineering duties.

The hard drive was not spinning at the time so this did limit the failure to a degree, if the storage device had been spinning then the HSA may have caused further damage to the disk surfaces or platters, this is due to the fact the the platters spin at 7200 rpm and the heads fly at a operational height of less than 1 micron, so the vertical displacement of torque or G’s to the disk only has to be minimal for it to come into contact with the disk surface causing damage.

This failure type was dealt with in the clean room and several techniques were employed, firstly the platters were transplanted to another known good chassis, this procedure is very complex, time consuming and requires specialist equipment, many companies can fail with this procedure, and here is why.
All hard drives are ‘synchronised’ platter to platter, that is to sat the the servo wedges, tracks and other vital areas are calibarated at the factory at the point of manufacture so any ‘slipping’ or moving of the rotational alignment could and very often does render the disk unusable, and more impertinently your data will not be accessible.

Following the platter transplant to a good known chasis with a good working motor, the HSA is the next part to be replaced, this also is not an easy procdure, it requires skill and dedication to source the correct parts and then install them in the new hard drive build.

Following the clean room the drive is then checked via the com port or TTL rs232 to USB port for firmware diagnosis, here a report of the hard drive firmware is diagnosed, if there are any issue here they are corrected and the drive is then taken to the image and cloning area to to cloned to a reliable destination.

The final part of the recovery is the file system reconstruction to its native format and a folder and file list sent to the client, a random amount of .jg, .raw.,tiff., nef files were launched as to check their integrity, all of which worked with no issues at all.

During the various stages of recovery the photographer was emailed and phoned with regular updates as to the progress and current position of the recovery, as he was very anxious to resolve this quickly, this we achieved in 5 days, to his immense relief.

Our advice if you accidentally drop or knock a hard drive, particulalry if the drive is on at the time please do not repower the drive as this will cause further issues and may compound the recovery at worst it may destroy your data.

If you are wedding photographer ensure that you have more than one back up in the filed so if you are using a Nikon and a Canon camera and have a decent size CF card, also it would be wise where time permits to backup to your hard drive and some other form of device such as an SD card, USB memory stick or similar, that way you should have a form of backup if your main drive fails.

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Overvoltage power surge fried external hard drive and disks

August 3rd, 2010

Overvoltage or power surged hard drives and disks are seen weekly in our lab and are usually caused by a user accidentally connecting the wrong power adapter to the hard drive.
This situation can occur if the hard drive is of external design and there are many other type power leads and connectors in the same area, some power adapter look very similar almost identical and may even fit into the socket for the external hard drive.

Many users then call our labs for advice and help to rescue their data after their hard drive has suffered from this failure type, do not switch the unit back on after this has happened, many users do attempt ‘another try’ which will only compound the recovery further, switch off and unplug the disk immediately.

Hard drives usually have a TVS Transient Voltage Suppressor which does offer a degree of fail safe for over voltage issues, also there are various Zener diodes and inductor coils  which will attempt to ‘clamp’ and reduce wrong polarity and excess current.

The PCB or printed circuit board will now have to be examined for electronic failures in said components and other SMC passive and active components, do not attempt to swap or exchange the PCB on your hard drive, this will not work, if the protection circuit fails and the current is high enough the HSA Head Stack Assembly could also fail, this then places the hard drive into a completely different and more complex area of recovery as clean room work will be required.

Our lab receives many enquiries from users who say that they have fried their PCB and hard drive and are looking at a very badly burned board, the spindle and or VCM Voice Coil Motor such as a Smooth chip can also suffer from thermal runaway issues and fry, this is very common, and simply finding a replacement board will not help as adaptive data is help on the ROM or MCU which is specific or unique to your hard drive and will not help.

GMR giant Magneto resistive heads are extremely sensitive and can fail from such over voltage and current failure types, this simply is not a user area for anyone to be looking at unless they have clean room access, knowledge and experience of all manufactures and models, again each hard drive has it’s own specific code for this area which may be the DCM: or MLC: Drive Configuration Matrix or Machine Level Code, and due to thermal and the unique design characteristics of each hard drive is ‘tunes’ to itself and so therefore parts location has to exact, even then there are many issues to deal with such as alignment of heads and other such issues.

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Dropped hard drive & disk

July 5th, 2010

A dropped hard drive or disk, particularly if it was running at the time can cause significant damage to platter surfaces and or the HSA head stack assembly as you would imagine.
Perhaps it was an external hard drive which was knocked over on the table? Worse still falling directly to the floor?
During R&D lab tests we have seen catastrophic failure to certain hard drives which are dropped from just 1″ while in operation.

Why does the hard drive become so damaged?
Spinning magnetic media operates at a typical rotation speed 7200 RPM (speeds vary on exact model) the HSA Head Stack Assembly literally files over the disk surface by the Bernoulli effect and has a distance of less than 1 micron, so any excessive  horizontal movement can cause impacts to the surface.

The term is ‘head crash’ and can strike fear into the hearts of any who have heard those words and have important data on the drive.

Do not on any circumstances open the hard drive, ‘just to have a look’, as some have tried as this will compound the recovery further.

In a class 10 clean room environment a full and professional diagnosis can be made and a clear process can be developed as to secure a successful recovery of data.

The HSA will often need replacement, and this is not as simple as it first starts, as hard drives are unique and require exact replacement parts to be fitted, and it is not simply a case of contact the manufacturer for parts, because they do not sell such parts, a replacement hard drive with the correct MLC machine level code or DCM drive configuration matrix, site code and or relevant dates are required, no mean feat I can tell you, and requires a full time position to track down such parts.

Following a dropped hard drive many users attempt to restart the drive, again this is not a wise move as further damage can occur, for those that have attempted to spin up the drive they may hear a beeping like noise, this could indicate that the spindle is now seized, and for a modern 1-2 tb disk this is a very serious and complex recovery as a procedure called a ‘platter swap’ is now required, and as the name suggests it involves moving the damaged ‘patient’ platters to a good working ‘donor’ which has a free working spindle, this procedure must preserve the rotational alignment of all disks and in some instances eccentricity issues must be catered for.

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