Hard Disks; Choosing A Hard Disk; Mo Disks - Akai DR4vr Operator's Manual

Hard Disks 69
10
Hard
Disks
This chapter
examines hard
disks.
Your
DR4vr
should
already
have
an
optional internal
hard
disk
installed,
so you have everything you need
to
be
able
to
start
recording.
If
the hard disk
has not
yet
been
formatted, see "Formatting
New
Disks"
on page
74.
If
you want
to
increase the available recording
time by adding
more
storage,
read through
this
chapter
to
gain
a better
understanding of
how
the
DR4vr
works
with hard
disks.
When
upgrading,
you can keep
the
internal
hard
disk
and
just
add an
external hard disk
via the
SCSI-A
bus. Alternatively,
you
could
replace the
internal
hard
disk with a
larger one.
Only
certain hard disks can be used with
the
DR4vr,
so please consult your Akai
professional
dealer.
(Also, please see
"ABORT MESSAGE
ON-OFF
mode"
on page
78.)
Choosing
a
Hard
Disic
There
are
many
types of hard
disks currently
available,
each with
slightly different
specifications.
Your Akai
dealer
will
be
able
to
provide
you
with information about which
hard
disks are best
for use with
the
DR4vr.
The
following
points should
also
be borne
in
mind:
•
Is
the hard disk
fitted
with two SCSI
connectors? This
will allow
you
to
add
more
hard disks
simply
by connecting
to the
SCSI-A
bus
daisy chain.
•
Are
the
SCSI
connectors 50-
way Amphenol
types
like the
one on
the rear panel of the
DR4vr?
Some
manufacturers use
different
types of connectors
for
SCSI
connections.
Although
there
are connection adaptors
available,
it
is
much
simpler
to standardize with one
type.
•
Can
the
SCSI ID number
be
set?
Some
of
the
earlier external disk drives were
not
fitted
with
SCSI ID
switches.
If
each hard
disk can be
set to
any
SCSI
ID,
it
allows
greater
flexibility
when
setting up
a
SCSI
daisy chain.
•
Does
it
have
internal or external
SCSI
termination? Hard
disks supplied
with an
external
terminator can be connected
at
any
position
in
a
SCSI
daisy
chain.
Some
hard
disks
that
have
a
fixed internal
terminator
must
always be connected
at
the
end
of
the
SCSI
daisy chain, thus
reducing
setup
flexibility.
This
is
especially
awkward when
you have two
such hard
disks.
•
Ts the access time
fast
enough? Most
currently available
hard disks have
relatively quick access
times.
However, some
older drives
can be
quite slow.
When
the
DR4vr
is
playing
and
recording
at the
same
time, the disk drive
is
continuously reading and
writing
data. If
the hard
disk's average seek time
is
slower
than 19 ms, performance
may
be
affected.
• Is
the data transfer rate high enough?
This
is
usually measured
in
Megabits
per
second
(Mbit/s).
A
transfer rate
slower
than
1
.5MByte/s
( 1
2Mbit/s)
may
affect the
performance of
the
DR4vr.
MODisl(S
Magneto
Optical
(MO)
disks operate
more
slowly than hard
disks, so they cannot be used with
the
DR4vr
for recording.
However,
they can be used
to
back up your
data.
Version
4.0 !2/95