BASF 6106 - Recording Media; Recording Format

1.6. RECORDING MEDIA
1
.7
RECORDING
FORMAT
The BASF
Mini
Disk Drive uses
a removable
single
sided flexible
mini disk
as
storage media.
Fig.
1
-
2 shows
construction
and dimensions
of
a typical mini disk.
The recommended
recording media
for use with
the
BASF 6106
is the BASF
mini disk 606.
The
mini
disk
is
an
oxide coated
flexible disk
en-
closed in a
protective
plastic
envelope.
The
protective
envelope
contains
aperture
for head
contact,
index
detection,
write protect
de-
tection and
spindle
loading.
The write
protect
notch is
used to protect the
written data
on the
mini disk
(see 2. 2. 6.
Write
Protect
Detector).
The
format
of
the
data
recorded
on the
mini
disk depends on
the host
system.
The
normal-
ly
used encoding
scheme
for
the
BASF
6106
mini
disk drive is frequency
modulation
re-
cording (FM). This scheme
utilizes
clocks
to
define
bit cell times. The
presence
of
a
flux
reversal
between clock
pulses
is defined
as
a
"one''
bit.
The
absence
of
a flux
reversal
bet-
ween
clocks
is defined
as a
"zero"
bit.
On
the
write
data
and read
data
interface
lines
between
mini
disk drive
and
host
system
ev-
ery
pulse
represents
a flux
reversal
on
the
mini
disk.
SEALED
PROTECTIVE
JACKET
OXIDE
COATED
MYLAR
DISK
LINER
TRACK
00
TRACK
39
B^s
BTTCELL
WRITE
DATA
DATA
-j*c""LJ"D~L_nT
r
4
A1S
m
nn rn
i
I
FIGURE
1
-
3 .
FM
-
ENCODING
A
group
of eight
consecutive
bit
cells
orbit
positions
(B8
-
B1)
defines
a
byte. The
most
significant
bit
is defined
as
B8,
the least
significant
bit
is B1,
as shown
on
fig.
1
-4.
During
a write
operation,
the
most
signifi
-
cant
bit
B8 is
always
transferred
first.
Also,
when
the
data
is
being read
back
from
the
drive,
bit
8 of each
byte
will be
trans-
ferred
first.
i
MSB
;lsb
;
i
•
^8
D
8
F?
C
6
D
4
C
5
C
«
C
3
D
3
C
2
D
2
P.
D
.
'.
C
8
-
B8
-4-
B74-B6
-+-B5-4-
B4
«J-B3
4-
B2
-J-
B
I
-4"
B6
•B8-+-
B7-4-B6
1
I
B4
*{•-
B3*f-B2-*f-BI'
I I I
I
BYTE
FIGURE
1
-
2 . FLEXIBLE
DISK
CONSTRUCTION
AND
DIMENSIONS
FIGURE
1
-
4 .
BYTE
1
-
5