Theoretically, hard drives should not work, why do they?

Question

Within a hard drive is one or more very powerful magnets that control the movement of the heads. However, they don't erase the "magnetic data". Also, hard drive platters are made from stainless steel (which is non-magnetic). So how is magnetic data stored on non-magnetic material? And why are there incredibly stong magnets used internally within a hard drive? I am highly trained in electronics. Most of my electronics instructors would blame it on FM ("Freaky Magic"). Does anybody have a better answer. I'm close to believing in alien technology!

Answer 1

You just got your basic wrong. Try to reveal them again, and understand the ground physics first...

This webpage may help you to have preliminary understanding...

http://computer.howstuffworks.com/hard-disk.htm

Answer 2

Excellent question.

Actually, theoretically, a hard drive should work - even better than the early versions did.

The theory was better than the actual device or the technology to manufacture the drive as originally designed and first introduced in the early 50's.

The theory, for instance, called for the head to ride, not on the platter, but above it at a slight distance. Read head and platter technology at the time could not do this reliably.

For instance, the first hard drives had an oxide coating (much the same as Mylar recording tape - hence, the magnetic medium on an otherwise non-magnetic surface of the stainless platter) and a read head that actually contacted the surface of the disk. As might be expected, this resulted in rapid head and disk wear.

The magnets which control the linear seek arm(s) are shielded and located well to the rear of the platters.

And, needless to say, the hard drives of today, use thin film media, very high speed platters and a data density far, far greater than the original 14" (30 Mb!) single platters. But the theory is the same. The double platters became known as Winchesters (due to twin 30Mb platters, hence, 30-30)

Being well versed in electronics - you should never except "FM" as an answer to your questions. (And unless you live near Area 51 - you can bet it's not alien technology:-)

Answer 3

We could start with the drive system. Yes, there are very powerful magnets in the drive system. But the magnetic field is contained by putting steel/iron around the magnets to direct the magnetic fields. The stray magnetic fields are too weak to alter the data.

The disks themselves are aluminum, which is not magnetic. But they are coated with a film of iron oxide or something similar that is. A thin film is required to get closely packed magnetic regions.

Data is written on the thin film of magnetic media with coils that are floating extremely close to the film's surface. At such a close range, they can produce high level magnetic fields that can write/erase data.

Answer 4

YEP!! I agree with the #2 dude. Where did you get the Idea that stainless steel is non-magnetic. Try #405 stainless then ask the question again...

Answer 5

definitely relies upon on the determination and length of the movie. hardship-unfastened 480i movies are approximately 700mb each and each. 720i are approximately a million-2 gigs each and each. 1080i movies could be from 4-8 gigs. each so often there are greater beneficial archives for subtitles, trailers, DVD extras, etc. in case you artwork diverse movies, and an typical of a million.5 gigs each and each, that should theoretically be a hundred and fifty movies. i think of a hundred twenty five is a greater life like expectation.

Answer 6

If my researches are correct it is....... MAGIC!!!!!

Not really... just copied 2 other ppl...

Anyway, the 2nd dude is right.

YOUR INFO IS WRONG

HE IS RIGHT

For more info, talk to him!

Thanks---

G_Roskamp_3
Gavin

Answer 7

Most of your info is dead wrong, that's where your problem lies.

Answer 8

MAGIC!!!

Run for your life aaahh

Answer 9

MAGIC!!!