Sharp FDD-412A - Page 19

FDD412A/B
2.4.2
Handling
of
Recording
Media
Giv
(1)
(2)
(3)
(4)
(5)
(6)
The
(1)
(2)
(3)
en
below
are
general
cautions
for
handling
the
recording
media:
Do
not
pierce
the
medium
jacket
with
a
pin,
put
a
clip
on
it,
or
write
directly
on
it
in
pencil.
Store
recording
media
in
a
dust-free
place.
They
should
always
be
housed
in
their
respective
cases
and
placed
horizontally
or
vertically.
In
horizontal
storage,
do
not
stack
the
disks
more
than
five
high
so
as
to
prevent
deformation.
The
recording
medium
should
be
under
the
following
ambient
condi-
tions
for
at
least
5
minutes
before
use:
Temperature
:
10%
43°C
Relative
humidity
-
:
20
%
80%
Maximum
wet
bulb
temperature
:
29°C,
without
dew-condensation
Do
not
touch
or
wipe
with
solvent
the
oxide-coated
medium
surfaces.
Keep
recording
media
away
from
magnetic
fields.
Do
not
expose
recording
media
to
heat
or
directly
to
the
sun.
.3 Recording Methods
FDD
utilizes
two
recording
methods:
FM
and
MFM.
FM
(frequency
modulation)
method
Flux
change
does
not
occur
at
data
'0'
but
takes
place
at
data
‘1'.
Clock
bits
are
inserted
between
data
items
to
indicate
the
range
of
data
presence
(bit
cell).
MFM
(modified
frequency
modulation)
method
Flux
change
does
not
occur
at
data
'0'
but
takes
place
at
data
'1'.
Clock
bits
are
inserted
only
where
O's
are
continuous.
MEM
me
thod
as
ee
ae
VN
es
mesitateses-
|
[a
bal
ad
ed
Ee
(WINDOW)
Extracted
data
Fig. 2.6 MF Method and MFM Method
Comparison of FM method with MFM method
Table 2.6 A Comparison of FM Method with MFM Method
~13—