In most computers, the data you save gets stored on a hard drive. However the drive does not store your files in a straightforward way. When you save files on your computer the data is written magnetically by a fixed comb of heads stacked above one another. These heads pass between several magnetic discs, writing data as they go. In most cases, instead of storing files on one whole disk they are split up and distributed among the disks. This means that when we carry out data recovery we usually need all of the disc surfaces in good condition to get the data back.
How Hard Drives Store Data Across Multiple Heads
When required we can use a process to take the data from the drive one disc surface at a time. This can allow us to avoid using a failing head until we have the rest of the data extracted. When we have extracted all of the data the parts are rejoined to allow access the files. In some cases this is the only way to get the data back.
Hard drives do not allow access to individual disks during normal operations so we need to use specialist hardware and software.
Apple have recently announced a recall program for all iMacs with internal 1TB Seagate Hard Drives. These hard drives fail unexpectedly with no prior warning. We highlighted the failure of these hard drives in a blog back in 2009. You can check whether your iMac has an internal 1TB Seagate Hard Drive by entering your iMac Serial Number at this link.
If you have one of these hard drives that has already failed and you wish to recover your data, then please contact us.
Following the success of our local data recovery partnership with Novatech, we now have expanded our partnership services to cover Novatech’s other stores nationally. You will find our leaflets at the service department counter in your local store.
We have recently recovered a RAID 5 array which consisted of three of these ST373454LC SCSI hard drives. These are solid, weighty drives, which don’t give off a great deal of vibration, despite spinning at 15,000 rpm; 3 times faster than most laptop hard drives!
Upon opening one of the drives for cleanroom rework we discovered why these drives spin so quietly. In the picture below you can see that although the drives are standard 3.5″ form factor, they actually have 2.5″ disk platters. These smaller disks create less drag, and therefore can spin faster without stability problems.
Inside a ST373454LC Hard Drive
These drives are not alone in mixing up the form factors. The popular WD Raptor drives also use a similar design.
Of course the biggest downside to using smaller disks is the lower storage capacity. Typically SCSI hard drives are much lower capacity than their SATA counterparts, so this trade-off is acceptable for the speed and reliability increases. The relatively low capacity is further mitigated when the drives are used in RAID arrays.
The Register has today posted two articles about the ongoing battle to expand hard drive capacities.
First is an actual device for sale, a 2TB Western Digital portable drive. This drive has a fancy new case and USB3 connection. It contains backup software and also the option to encrypt the data with a password. I wonder if it encrypts the data by default like some of their previous portables. (A bad thing!)
Second is a futuristic announcement from Seagate about their new HAMR technology. This new tech uses a laser to heat part of the disk before magnetising it. This apparently allows for much higher densities, theoretically paving the way for 60TB hard drives. There doesn’t appear to be any products using this technology at the moment.
60TB drives will be fantastic for backups, but horrible to backup without a new, faster form of connection. These would take almost forever (exaggeration) to fill up by SATA.
This news helps prove that hard drives are far from dead. It will take a long time until SSDs can cope with such massive capacities, at a similar cost to these beasts.
These Seagate FDE hard drives encrypt the data automatically as it is read and written to the drive. As you save data to the drive it is encrypted immediately and can only be accessed when you input your user name and password. The drive will then be temporarily unlocked and allow the operating system to boot. Once the drive is powered off, it will be automatically locked again.
We have received several of these drives from customers who cannot access their data due to a hard drive failure. You may still b asked for the password, but the laptop will then fail to boot. This can be as a result of bad sectors or electronic problems. We can overcome virtually any type of failure and can return your data back to you decrypted and fully accessible on a new hard drive.
We see a lot of portable hard drives that don’t spin up when plugged into a USB port. All brands of hard drive can be effected including Hitachi, Western Digital and Seagate. The problem can be caused by power loss or sometimes due to mis-plugging of the USB lead. This causes the internal read heads to sit on the disc instead of parking on the ramp at the side.
The only way to overcome this problem is by taking the hard drive into our clean room to replace the damaged heads with good ones. This allows us to copy the data from the drive and store it on our server.
The repaired hard drives are not suitable to be reused after this sort of work as they will not work correctly.
Western Digital want to buy Hitachi Global Storage. The FTC will only allow this if WD sell of some manufacturing capabilities to Toshiba. This seems to be due to some anti-competition type laws. The strange thing is that Toshiba don’t currently make 3.5″ drives, so perhaps we will see some strange Toshiba branded WD drives? Who knows.
Maybe it will be like when Maxtor were bought by Seagate and brought out the STMXXXXXXXXX drives, which were simply Maxtor branded Seagate drives.
We have just competed a successful recovery from an HP Smart Array E200i RAID array. Not a standard case this. It had x3 DG146BB976 2.5″ SaS drives, two of which had been overwritten with a new RAID 1 mirror.
We found the disk order which was not the same as the labelled numbers. This is often the case. Also, due to the rebuild that had occurred we had to drop one of the disks and virtually rebuild it using the parity information from the other disks.