Mitsubishi Electric M4853 Maintenance Manual page 31

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