BASF 6106 - Page 6

I .8.
TRACK
FORMAT
TRACK
GAP
The
tracks
of
the
mini
disk
may
be
formatted
in
numerous
ways,
depending
on
the
formatter
of
the
using
system.
The
BASF
6106
can
write
and
read
hard
or
soft
sectored
track
formats.
The gap
between the
last
data
field
and the
index
puis
is
defined as
Track
Gap. It
varies
slightly
in
length,
due
the
write
frequency
tolerances
and the
disk speed
tolerances.
It
is
nominally
101
bytes in
length.
1.8.1
SOFT SECTORED
TRACK
FORMATS
In
a
soft
sectored
track
format
the
user
may
record
one long
record
or
several
smaller
re-
cords
on a
track.
Two
soft
sectored
track
formats
with
16
and
9
sectors
per
track
are
described
in
the
following
chapters.
ADDRESS
MARK
(AM)- BYTE
.
The
soft
sectored
track
format
needs
unique
bit
patterns
to
identify
the
beginning
of ID
and
Data
Fields
for
synchronising
the
dese-
rializer
circuit in
the
host
system.
The
unique
bit
pattern is
called
Address
Mark
(.AM).
AM-
patterns do
not
contain
clock
bits
in
all
bit
cells
(all
other
data
bytes
must
have
clock
bits
in
every
bit
cell!).
There
are
three
different
AM-
patterns
used:
l.S.1.1.
SOFT
SECTORED
TRACK
FORMAT
KITH
lo
SECTORS/TRACK
a'
128
BYTES
This
format,
which
is
recommended
from BASF,
is
shown fig.
1
-
6. It
is
similar
to
the
IBM
-
format.
The
befinning
of
a
track
is
indicated
by
a
physical
index
pulse.
Every
record
is
prece-
ded
by
a
unique
record
identifier.
Record
identifiers
and
data
fields
are
separated
by
gaps.
The
gaps
are
necessary
to
allow
the
up-
dating
of
a
data
field
without
disturbing
ad-
jacent
fields.
INDEX
GAP
This,
gap
starts
with
the
index
pulse
and
is
always
16
bytes
in
length.
It
is
not
affected
by
any
update
write.
IDENTIFIER
GAP
This
gap
consists
of
11
bytes
FF
X
and may
vary
slightly
in
length
after
the
data
field
has
been
updated.
DATA
GAP
This
gap
separates
the
data
field
from
the
following
ID-
field
and
is
27
bytes
in
length.
It
will
vary
slightly
in
length
afterthe
data
field
has been
updated.
•
ID-
AM
•
DATA
-
AM
in
front
of a
ID-
Field
in
front of
a
Da-
ta Field
DELETED
DATA-
AM
in
front of
a
De-
leted
Data
Field
These
AM are
shown
on Fig. 1
ID
-
AM:
SEP
CLOCK
(C7)
SEP
DATA
(FE)
DATA
-
AM:
SEP
CLOCK
(C7)
SEP
DATA
(FB)
f
«
n
F.
c
?
h S
inn
I BYTE
III!
C
4
S
<7
D
8
D
7
D
6
D
5
D
4
D
3
h
c
8
C
7
C
6
C
5
C
4
C
3
°2
C
l
f-8
n n n
Dg D
7
D
6
D
5
\
D
2
D,
DELETED
DATA
-
AM:
I
c«
c,
%
c
5
(^
c
3
tj
c,
ic
8
I
"
"
p
I
>
SEP
CLOCK
(C7)
SEP
DATA
(P8)
ii
«
ii
K
D
8
D
7
D
6
D
5
D4
FIGURE
1
-
5
.
ADDRESS
MARK
PATTERN