Over the years I've sold and repaired
lots of computers and found that the most common failures are
optical drives, motherboards, and hard drives, in that order.
Motherboards fail generally because the decoupling capacitors fitted to smooth the low voltage rail get quite warm, leak, and eventually develop a high resistance allowing spikes to interfere with the working of the microprocessor.
The worst failures are of course hard drives and, I think, apart from motor bearings just wearing out, getting noisy (a warning that all is not well) then failing to spin up properly, the most common cause is bad design.
The first instance I came across that is worthy of note is a particular Fujitsu model of yesteryear. This used a complex chip supplied to the manufacturer by a sub-contractor. In turn, the sub-contractor used a specific type of glue in the manufacture of the chip that decomposed when hot into a highly corrosive chemical and ate away the internal bits of the chip. All the drives manufactured over a period of a year effectively had within them a time bomb that would cause the loss all the user's data.
The latest hard drive problem I've met concerns Seagate drives. I'm not altogether sure of the whole story, but it goes something like this
Built into a hard drive is a program, called "firmware", that determines how the drive stores and retrieves data and a few frills, such as monitoring and reporting errors.
As I understand it the Seagate designers' decided to change the design of their Barracuda drive and employ some of the platter space (the platters are where your data gets stored) to carry some, but not all, the firmware.
Most of the firmware is carried in a
chip on the circuit board attached to the drive, but because
the programmers ran out of space, a little is put onto the platters.
The problem with the Seagate Barracuda
drive was associated with a slip-up by the programmers who wrote
the firmware, in particular version "ST15".
In the fault condition, because the
hard drive wasn't actually busy, and didn't actually know the
busy flag was set, it was oblivious to the fact that the outside
world couldn't access it. In fact it was a stalemate. The computer
could not access the drive and arrange somehow to reset the busy
bit, and the hard drive was just sitting there waiting to be
used, but completely inaccessible.
When faced with this difficulty there is very little that can be done by an ordinary computer user.
A glance at Seagate's website indicated they were being very coy about the affair but, a search of the Internet revealed I wasn't the first to be aware of the Barracuda drive problem.
Mostly, any positive feedback pointed in the direction of a particular data recovery company that was offering some free software and a schematic for a special piece of hardware that could be connected to the factory setup pins of the hard drive and so reset the busy flag.
I downloaded the free software and purchased the parts for the special box of tricks.
Next I investigated the exact details of how to go about sorting out my particular Barracuda drive. Drat the free software was designed to fix the previous version of the drive it seems the bad firmware was used in successive versions of the Barracuda before being spotted. A call to the firm that supplied the free software quickly revealed that the version I needed wasn't free, it was $500. This included the special interface cable so I didn't have to make my own.
I didn't feel like parting with $500.
I returned to the Seagate website and
penned a message to them. The data is very very important to
my customer, I explained. It certainly was as he hadn't backed
up his prolific email exchanges.
I received a phone call from TNT (the carriers).. requesting me to print out an advice note (to be attached to an email.. to follow) for their driver who was speeding towards me that very minute I did so and hastily packaged the hard drive with an address supplied in the email from Seagate.
A short time later the TNT driver knocked on the door and accepted the package, remarking that the address I'd put on the box was wrong not Seagate in the UK, but a firm in Holland..
The next day I got another email stating that my hard drive was fixed, and a day or two later the repaired drive was delivered by TNT; in fact it arrived so early I was still in bed and had to collect it from a neighbour.
Full of confidence I fitted it to my customer's computer and low and behold it fired up to the XP Desktop exactly as it was before the busy flag had been set. A quick check revealed that the firmware was now the latest version so, hopefully, the drive will be good for several years.
What about a RAID system you might ask?
This would have a second hard drive carrying a mirror of the
boot drive so that failure of one drive would not result in loss
The final phase was to make a backup
of the repaired drive, just to be safe, then reformat the second
drive and wait till the RAID software finished its mirroring.
It's a pity that Seagate didn't advise resellers, via suppliers, to update the firmware on any Barracuda drives they'd supplied.