AMSTRAD PC1640 - Understanding Bad Sectora on a Hard Disc; RP4;RP5-2 Diagnostics

UNDERSTANDING
BAD
SECTORS
ON A HARD
DISC
Most
hard
discs
have
a number
of
manufacturing
faults,
this is
completely
normal.
These faulty
areas are
known
as
bad
sectors.
During
the
formatting
procedure
of a hard
disc
these
bad
sectors are
marked
so that
they
are not
used,
therefore
they
do not
cause
any
problems.
There is
allowance
made
for
one
bad
sector in
each
megabyte
of disc
space.
Therefore
as one
bad sector
equals
1
0240
bytes
the
total number
of
bytes
allowed
on
a 20
megabyte hard
disc is
204800
bytes which
is 200k.
To
see the
amount
of
bad sectors
on
a hard
disc type
CHKDSK
at the
C> prompt
or place
your
MS-DOS
disc
in drive
A: and
type
CHKDSK
C:
It is sometimes
suggested
that
by running
HDFORMAT
the
number
of
bad sectors
can
be reduced.
This
is
not
correct.
%
RP4/RP5-2
DIAGNOSTICS
The
PC1
640
diagnostics
card
is RP5-2
as opposed
to RP4
which
was
the PC1
51 2
diagnostics.
RP5-2
is
a plug in
diagnostics
card
that
can be
fitted
to any of the
1 640
expansion
slots.
It
comes
supplied with
an
IC clip which
is
placed
over IC108.
Note
that the
pin on
the clip with
most
wires
attached
connects
to pin 10
of IC108.
Also
supplied
are
two loopback
connectors
one
each for
serial
and
parallel
ports.
There
is also
a disc
supplied
with
RP5-2 which
will
check
the
VDU.
It
should
be noted
that RP5-2
will
perform
on a PC1
51 2
exactly
as RP4
but RP4
will not
run full
tests on
PC1640.
The
reason for
this is
that RP4
cannot
check
the 1 640
ECD
display.
When using
RP5-2
on
a 1640 the
VDU
tests are
not
performed
but are run
from the
supplied
disc.
If using
RP5-2
on
a
1
51
2
the
VDU
tests are all
performed
as they were
on RP4.
Note
that there
are no
selection
switches
to
choose
between
1 51 2 or 1
640 as it is
automatically
selected
by the
card.
The
1640 VDU tests
contain
all those
previously
performed
by RP4
but it
also
contains extra
1640
specific
tests.
For
those
people who
already
have
RP4 the
necessary
chips
to upgrade
to an
RP5-2
are
available.
Full instructions
on the
use of RP5-2
are
included
with the
product.
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