Read/Write Head never actually touch the platter?

[SHENGTON]

Hello guys, good morning.

Awhile ago, I'm having a research about "How Hard Disk Works?" and Google gave me the of HowStuffWorks. While reading the topic "Cassette Tape vs. Hard Disk" this line makes me curios.

In a cassette-tape deck, the read/write head touches the tape directly. In a hard disk, the read/write head "flies" over the disk, never actually touching it.

Can somebody explain this more deeply little bit. I mean, how the data is being read and write without touching the platter?

Hope somebody will give a brief explanation with this.

[Geek-9pm]

Years ago I worked in Hard Drive Research. Rather than bore you with the old technology that existed back then, here is a more up to date article. It is basic, but technologically accurate.
http://en.wikipedia.org/wiki/Disk_read-and-write_head
This sometimes called an 'air bearing'. The air  prevents the head from hitting the media. Most of the time. The media has a thin coating to protect it from the few times the head hits the surface. When the drive shuts down, the head moves to the outer track and 'lands' in that area.
Some types of hard drives will unload the head with a ramp. This was the older technology. Also, Thin film heads have been the dominate thing for many years. The article mentions some of the new ideas that may keep hard drives around for a few more years.