View Full Version : Bad, bad lesson

1st January 2009, 11:30 PM
Have I learnt a bad lesson or what!

NEVER EVER put a magnetic thing on top of your MB trackpad. Ever.

I thought this was a myth until yesterday where I was dumb enough to accidentally place my indoor antenna for the DVB-T tuner on top of the trackpad.

The next 24 hours were the most gruelling of my life - "invalid node structure" errors, failed TM restores, failed Leopard reinstallations, to eventually "SMART reports your HDD has a serious hardware failure. Please replace ASAP" (or to that extent). Holy shit. This is so annoying - second hard drive failure in a month (different hard drives).

If it weren't for TM and the 1TB backup drive I bought in June, I don't know how I could have survived.

Just a question - when TM restores your HD on a (presumably new) HDD, does it restore the original errors (if any), or what? I don't know.

2nd January 2009, 04:26 PM
Time machine can restore whatever selected back-up you'd like restored. I imagine you'd choose one from before putting the tuner on top of the trackpad.

Bastard Sheep
2nd January 2009, 05:07 PM
Better yet, never put a magnet anywhere near where a computers HDD is, as that's how HDD's store data and you're sure to corrupt them.

At work we have magnets for holding sheets of paper to the partitions, I love the people who use them to hold sheets of paper to their computers.

2nd January 2009, 05:19 PM
You think by now, hard-drives would be shielded by such things as this?

Can anyone shed some light on this?

2nd January 2009, 05:21 PM
Bad luck I guess, lesson learnt, at leas you had good backups; its a terror to love data.

Reminds me greatly of this (bastard sheep):

\/\/ Yes I think it is a set up too, but still funny. I first saw it on pouet.net, which kind of explains things a bit :P

Bastard Sheep
2nd January 2009, 05:42 PM
I still think that photo is a setup (ie, done on purpose for a laugh). :)

2nd January 2009, 06:05 PM
Unless your antenna has a massive medical imaging electro magnet inside it, I highly doubt that it was related. And floppies can be attached to a fridge or failing cabinet with a magnet no problems :P

2nd January 2009, 07:07 PM
You think by now, hard-drives would be shielded by such things as this?

Can anyone shed some light on this?

Unless I'm mistaken, magnetic fields are impossible to shield against.

A lump of lead between two magnets will not prevent them attracting or repelling each other.

2nd January 2009, 07:25 PM
It is possible to shield against magnetic fields (mostly).

An iron or steel plate will shield against a single magnetic source (the wider the plate the more the shielding). An iron or steel box around a magnet will keep the field confined within that box (assuming that the metal is thick enough... as the field gets stronger the metal needs to be thicker). A superconductor will also have a shielding effect for a 2 magnet field.

What in effect is happening is that the majority of the magnetic field flows within the iron or steel rather than spread out into free space. Hence the need for more metal for a stronger denser field.

2nd January 2009, 07:28 PM
well its either causally connect or a huge coincidence (yes isn't it just the eternal question). only this time shall i say it was causation. lesson learnt =( i have to go two weeks w/o my laptop again until the people at quicktron come back from holidays and repair it. i just knew i should have got that more expensive apple warranty rather than the myer one when i bought my laptop!

make you value a MBA flash drive I guess..

2nd January 2009, 08:24 PM
I'd say it's a sheer coincidence that your hard disk decided to fail at this very time, and not due to the small magnet you placed on top of your hard disk. You need a incredibly large, powerful electromagnet near a hard disk to come even close to causing possible data loss. And when you think about it, computers are near magnets all the time - internal speakers, magnets in hard disks themselves, and what about the Magsafe connector on Intel notebooks! A tiny fridge magnet as in your TV tuner's antenna is going to do jack all.

Some interesting reading:

A PC full of magnets (http://www.dansdata.com/gz067.htm)