Data to be recorded on the floppy disk is grouped in various
blocks.
There are bits, bytes, sectors, tracks, and sides.
encoded onto the disk by three possible means:
techniques.
These bits
number of bytes per sector to define the actual recording format
used.
All of this is defined by the host system; the disk drive
just records and detects flux reversals on the disk.
8.1
As
stated
en c o d i n g
a d v a n t a g e s
accepted standard is MFM (also called Double Density).
8.1.1
FM
(Frequency Modulation)
8-1.
decoded by used of inexpensive one-shot multivibrators.
It can do this because each data pulse is between two
clock
window" very precisely.
8.0 RECORDING FORMAT
are collected
before,
there
bits
on a f l o p p y
and d i s a d v a n t a g e s ,
It is the simplest form of encoding, and may be
pulses,
thereby
Figure 8-2 Figure Read Encoding
FM, M F M , or MMFM
together
are
three main methods
disk.
A l l
but the g e n e r a l l y
encoding is shown in Figure
rigidly
defining
The bits are
in a certain
of
h a v e
some
the
"read