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- m18
- O3
- RF0 0 639 479
- O1
- T5
- RE8 9 630 451
- O0
- T1
- te30 15 DEFAULT
- The timing crystal emits an
- electronic tick, tick, tick at a
- very high rate of speed. The timing
- chip adds these ticks to the time
- and date. The battery keeps this
- going. Whenever the computer is
- turned on, the battery is recharged.
-
- The computer loads a program
- from a disk into the RAM. Hard
- disks usually spin at 3600 revo-
- lutions per minute and floppies run
- at 300 RPM. The hard disk can hold
- more information than a floppy, but
- their principal of operation is the
- same.
- The surfaces of a disk are
- coated or plated with a magnetic
- metal. A small recording head is
- placed very near each surface. The
- head can be moved in and out along
- the radius of the disk, so that it
- can read or write along any of many
- tracks, called cylinders.
-
-
- ~
- te341 15 DEFAULT
- If you move a magnet past a
- wire, an electric current is
- generated. This is also how disks
- work. Spots on the disks are
- magnetized, representing bits of
- bytes. As the disk spins by a
- small coil in the head, as the
- spots pass, spikes of electricity
- are produced. These spikes are
- translated into bytes and passed
- to the CPU and the RAM.
- If you run a current through a
- wire near a magnetizable metal,
- the metal will become magnetized.
- This is how writing to a disk is
- done. As the disk turns past the
- coil in the head, the coil is
- energized every time an "on" bit
- is to be written to the disk,
- resulting in a magnetized spot.
- The switching on and off of the
- electricity flowing through the
- head is very fast.
-
- ~
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