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I'm getting an increasing number of enquiries for assistance with hard drives that have gone faulty. With this in mind, I'm thinking of logging these to a forum where people can offer advice to enquiriers. Here are two:

1. Sonnics 250GB external hard drive has stopped responding when plugged in – light does not come on as usual and does not show up on desktop. Used it this morning and it was fine, has not been dropped or damaged that I know of, just seems completely random. Does not make any noise or seem alive at all.

2. We have a 1TB Seagate Expansion external HD that has suddenly stopped being recognised on our laptop and TV. The white LED flashes but nothing happens. The HD doesn't click, but makes a whirring sound. Not sure how much is on there, but all we want are any documents and pictures back. Please advise costs.

At the moment I am directing people to local data recovery service providers who are located near to them such as http://www.dataclinic.co.uk/dataclinic-locations/ and the sites listed on http://janschon.edublogs.org/, who then pick up the enquiry and contact the user direct.

An established data recovery blog run by Clive Naylor highlights data recovery issues and recommends companies from time to time. Clive's blog can be found at http://clivenay.beeplog.com/ and and example company at http://clivenay.beeplog.com/341275_5194537.htm.

Reading Google's Web Master Guidelines at https://support.google.com/webmasters/answer/35769?hl=en it seems they place a lot of emphasis on how fast a site loads. This is not surprising as these days, your typical human browser is not willing to wait longer than a couple of seconds for a web site to load before losing patience and going somewhere else.

With this in mind I decided to run a Google Insights speed test (https://developers.google.com/speed/pagespeed/insights/) on my web site, and found that I only scored about half marks and also had a lot of recommendations in order to improve my site's speed.

I spent the next 2 days or so implementing all these changes and managed to get the speed up into the 90% band for desktop sites and 75% for mobile sites. I then waiting about 2 weeks whilst monitoring my sites rankings and waiting for the improvement in speed to be reflected in increased rankings. However, nothing happened. I was rather disappointed. Making my site more like Google would like it to be should be reflected in web site rankings you would think? Apparently not.

So now I shall downgrade web site speed in my list of priorities for my web site and instead keep my focus on content.

There's been some interesting blog posts on the Data Clinic web site lately at http://www.dataclinic.co.uk/.

For those of you who like techie information relating to computer disks, data and what to do if you find yourself in the unfortunate position of losing data, the Data Clinic blog is the place to go as it's full of real world examples of data loss situations and tells you how to go about getting your data back. This information isn't just confined to hard drives, but also includes mobile devices like tablets and smart phones.

First of all I didn't know that it's not possible to repair and damaged hard drives. Although we make not think they look very complex. hard drives are very clever devices that are difficult to fix if they go wrong. Here's a great post about why it's not possible to repair a damaged hard drive.

The blog posts aren't confined to hard drive problems and how to resolve them though, there are other related articles. Hacking is a big problem these days and most often the weak point in the chain is the simple password that is used to protect a system's data. Use of weak passwords renders systems highly vulnerable to attacks, so this guide shows you how to construct a strong and secure password that's easy to remember and very difficult for hackers to break.

Finally, there's a typical cross section of the various different types of enquiry that Data Clinic receive - in this example you can read people's enquiries about recovering information from mobile phones, external hard drives, PC's and Macs.

So go and have a look at this site - as I say, it's crammed with information about hard drives and getting data back from damaged devices.

Int13h functions provide low level disk input / output capability. Since disk systems usually funnel all i/o operations through these functions, many add-on and three-part products hook into then and relocate the original functions to other vectors.
One of the most popular methods data recovery companies use to reset hard drives and get them out of error states is to issue a 'reset disk' command via the int13h interrupt.
You can try this yourself - grab yourself an assembler and program the registers as follows before issuing the int13h command.

Interrupt 13h - Function 00h
Reset Disk System

Purpose: Restores disk system conditions to power-up state.

Registers at call:
AH=00h
DL=drive (if bit 7 is set both hard disks and floppy disks are reset)
Details: Forces controller to recalibrate drive heads (seek to track 0)

Return Registers:
AH=status

00h successful completion
01h invalid function in AH or invalid parameter
02h address mark not found
03h disk write protected (floppy)
04h sector not found
05h reset failed (hard disk)
06h disk changed (floppy)
07h drive parameter activity failed (hard disk)
08h DMA overrun
09h attempted DMA across 64k boundary
0Ah bad sector detected (hard disk)
0Bh bad track detected (hard disk)
0Ch unsupported track or invalid media
0Dh invalid number of sectors on format (hard disk)
0Eh control data address mark detected (hard disk)
0Fh DMA arbitration level out of range (hard disk)
10h uncorrectable CRC or ECC error on read
11h data ECC corrected (hard disk)
20h Controller failure
40h Seek failed
80h Timeout (not ready)
AAh Drive not ready (hard disk)
BBh Undefined error (hard disk)
CCh Write fault (hard disk)
E0h Status register error (hard disk)
FFh Sense operation failed (hard disk)

I'm asked from time to time about Lacie hard drive pcbs: sometimes a problem like an electrical short will damage the hard drive's PCB and the common thinking is that a simple PCB changed should suffice, rather than sending the whole drive off for repair. This common knowledge is wrong - 10 years or so ago it was possible to swapping hard drive controllers boards or pcb's and the drive would work normally again, nowadays this is something that doesn't happen. This is because the information now on the hard drive's pcb contains unique data to the drive it is housed on, so changing the controller board - swapping a broken on with a working one will no longer work.

For all types of Lacie hard drive problem, contact Lacie or Data Clinic at http://www.dataclinic.co.uk, even controller board problems. If you drop your Lacie hard drive and the drive then begins to beep or tick then it's important you dont switch the hard drive on any more - this is because the noise your are hearing in the hard drive trying to start, but the platters inside the hard drive are being impeded, probably by the heads that read and write the data or by the spindle, which has developed a fault. Mechanical problems like this are best handled by data recovery specialists such as Data Clinic who will be able to assess the situation and restore the data from the hard drive without sustaining any further damage.

Flash memory in the shape of SSD hard disks is a comparatively new development, and SSD hard drives are now available in impressive capacities such as 80Gb and 120GB. This capacity of storage would have been enough for anyone 10 years ago, but now that movies are in high definition and music is in 192kpbs high quality and the photographs we take are several megabytes each, our need for massive amounts of storage is also much greater than it used to be.

A report in today's UK edition of The Register compares SSD takeup and popularity with HDDs and finds that SSD are falling by the wayside month by month. The reason? They can't keep up with the capacities now being squeezed from HDDs (Hitachi currently sell a 6TB hard drive) and the cost per megabyte of SSD storage is significantly higher that for HDDs.

All this is good news for you and me - HDD's are cheaper to buy the SSD's and also considerable easier for computer support companies to maintain.

You can read the full article in The Register here: http://www.theregister.co.uk/2014/12/09/no_flash_datacentre_takeover/