A Modern Computer Problem

[GeoffS]

Little Festo - Nup! Won't do it. Only something that will overwrite (many times) everything on the disk will do the trick or physically destroying the platters not just the hard drive case.
True, most of us don't have anything very important on our hard drives (apart from credit card numbers, passwords, banking info. etc) and just making the drive unreadable on any normal computer makes the job of getting the info very difficult. However there are some people 'out there' who thrive on challenges like that, and, having put all that effort into finding the info think they have earned the right to use it.
They get their kicks their way, I get mine making life totally frustrating for them!
Happy Hammer - even that isn't perfect - really smart gear can (sometimes) find the old data under the new. That is why new garbage must be written many times. All 'ones' then all 'zeroes' over and over again.

Cheers

[Grunt]

I think this thing about having to write zeros and ones over the same same spot on the disk to ensure that you can't read the 'old data underneath' is a myth that is propagated by sellers of cleansing software.

Computers 101.

Computers store things in binary. That is either a zero or a one. A group (8) of these bits are called a byte. For a computer to store the letter 'A' for example is '01000001' in binary. The letter 'M' is '01001101'.

When it writes it to the hard disk it Magnetises or demagnetises little spots on the disk to represent the 0's and 1's. 0's are demagnetised and 1's are magnetised.

The computer must absolutely read back exactly what it writes. It wouldn't do much good for a computer to write the letter 'L' to the disk and then read back an 'F'.

Since the disk can only have it's little spots on the disk magnetised or demagnetised and there is a guarantee that what is written and what is read back is identical, there is no opportunity for something 'underneath' the to be found.

[Tristan Croll]

Not so much "under" as "around". The write heads on a hard disk always have a little bit of play in them. This means that when you overwrite a track, there is almost always a little border which retains the original data. There can actually be quite a number of these borders, so that data that has been "overwritten" up to (I think) four times can often be recovered. This treatment is incredibly expensive both in terms of money and time, so it is generally reserved for suspected terrorists, paedophiles etc.

[HappyHammer]

Sounds like a job for the sledgy and the fire then.

HH.

[jow104]

To Happy hour
My latest harddrive is 160gb what can I fill it with, and live long enough :confused:
In fact an advert this weekend for a computer quotes over 500gb capacity.

[Grunt]

Ok, if there is a little play in the heads, the computer writes some data. Which of the 4 borders does it read? When you get 200+GB on a little 3 1/2" drive, the little magnetised bits are really, really close together. I don't see how there can be any play in the heads and still guarantee that what is written is read.

I think we should stop now, because we're probably boring the crap out of the rest of the people on the BB.

[HappyHammer]

To Happy hour
My latest harddrive is 160gb what can I fill it with, and live long enough :confused:
In fact an advert this weekend for a computer quotes over 500gb capacity.

Just copy and paste and you'll get there pretty quickly, copy OS say 3Gb you have 6Gb then 12, 24, 48, 96, 192, pretty easy.

Also it's Happyhammer don't you have football in Devon or are you thinking about your next binge?

HH.

[Grunt]

My latest harddrive is 160gb what can I fill it with, and live long enough

, music, DVD's.

[GeoffS]

Grunt - Let's just say, it can be done and leave it at that.
Cheers

[HappyHammer]

, music, DVD's.

and microsoft patches...

[Tristan Croll]

Ok, if there is a little play in the heads, the computer writes some data. Which of the 4 borders does it read? When you get 200+GB on a little 3 1/2" drive, the little magnetised bits are really, really close together. I don't see how there can be any play in the heads and still guarantee that what is written is read.

I think we should stop now, because we're probably boring the crap out of the rest of the people on the BB.

Did I mention that this border is really, really small (even compared to the really, really small track)? The standard read head goes with the majority vote - to read the border data you need an extremely miniaturised read head.

[jow104]

The only connection to football is West Ham United. Its their nickname.
So it must have been the other thought.

[HappyHammer]

The only connection to football is West Ham United. Its their nickname.
So it must have been the other thought.

You have it, I'm a West Ham fan! I think it's payback for something bad I did in a previous life or just geography I'm not sure.....

HH.

[jow104]

Another problem arises from selling your old computer.

I sold my old computer for hard cash to 3 Polish lads who were very computer literate. What else were they going to use the computer for?
It might have nothing to do with credit card numbers.

Perhaps they want my identity to do some other activity. They are almost untraceable immigrants without fixed abode. They are probably shacking up at some address on a very temporary basis and can move on within minutes if they desire.
I put the thread up purely to show the dangers of selling on a computer to an unknown purchaser or passing on to family connection which subsequently could still finish in other hands innocently.

[HappyHammer]

What fun it must be being a part of the EU...