Formats - IBM 3340 Reference Manual

TRACK CAPACITY
The number
of records
that
can be recorded
on
a
track
depends
on
the record
size.
The
following
equation
can be used
to
determine the
number
of equal
length records per
track.
The
home
address
and
standard
RO
space
and
skip defect are taken into
consideration.
Equal length records
_
8,535 (track capacity)
track
C
+
KL
+
DL
(bytes/record)
where:
C(overhead/record)= 167
if
KL
=
=
242
if
KL
#
KL=
Key
length
DL=
Data
length
The number
of records
(n)
of different
key and
data
lengths that
can be recorded
on
a
track
must
satisfy
the following equation (the standard
RO
is
already
accounted
for):
Records
n
Track
=
8,535 >
£
C +
KL
(»)
+
DL
G)
i=
1
When RO
is
not standard, the following
formula should
be
used:
Records
=8,706 >
[KL(o)
+
DL(o) +
C-4] +
Track
n
£[KL(i) +
DL(i)
+
C]
i
=
1
where:
C =
167ifKL
=
C -
242
if
KL
#
The
tables
shown
in Figures 7
through 10
give
maxi-
mum
sizes
of n equal-length records
on
a track
where
n
is all
possible values.
Track,
cylinder,
and
data
module
capacities are given in
both
the
number
of
bytes
and
the
number
of records.
There
are tables for records
without
keys,
and
for
records with keys. In
all
tables,
overhead
for
home
address
and
standard record zero
(KL
=
0,
DL
=
8)
is
already
accounted
for.
where:
C
=
167ifKL
=
C
=
242
if
KL
/
Formats
9