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FORMAT COMMAND
15. 1 -- Use
1.
Rew~ite
the sort sector addressing
info~mation
on
each
cylind~r
(Appendix F contains a
desc~iption
of the diskette format),
2.
Initialize
·eve~t.J
byte
of
each
sector
to the
hexadecimal value
$ESI
3.
Re=read each cylinder to verify
that
the
CRC's
are good and that the diskette is readable.
The
above
process
terminates
when
the
diskette
is
completely formatted or
when
a
diskette
controller
error
occurs
repeatedly.
In the rormer case,
control is returned
to
MDOS.
In the latte-r ease,
the FORMAT command tIIi!l displaq
the
diskette
controller
error with the standard "PROM I/O"
error message.
The diskette is not necessarily
unusable
ir
such errors occur.
The
FORMAT
command should be re-run after
having noted the physical sector number at
which
the
error
occurred.
IT
the
same
error
occurs at the same physical
sector number
a~te,..
three
attempts
at
running
the
FORMAT
commandl
then the oxide on the diskette is probably damaged.
The'diskette is unusable in
such
cases.
I~
the
unusable
diskette
is
inspected
careFully
by
manually
turning the
diskette
~ithin
its
protective
envelope,
a
mark
or
indentation can usually be found on its surface.
The
FORMAT
command
can be used to format Single-sided
diskettes on the single- and
double-sided
Calcomp
EXORdisk
I I / ! I I
systems
O~
on
the
single-sided Pertee EXORdisk II
systems;
noweverl
double-sided
diskettes
can
only
be
formatted on the double-sided Calcomp EXORdisk III systems.
15.2
Messages
The
only
messages
that the FORMAT command can display
a~e
the p,..ompt shoUln above,
asking
if
the
diskette
in
the
specified
<unit>
is
to be Formatted, and the standard
PROM
IIO
error message,
indicating
that
a
diskett~
controller
error was encountered during the formatting process.
15.3 Example
The
Tollowing
example
shows
the FORMAT command being
used repeatedly
after
an
error
is
detected.
Since
the
physical
sector
number
of
the
error keeps increasing,
it
indicates that the FORMAT command is able to
re~rite
more and
mo~e
of
the
diskette;
however, at one point,
the physical
sector number is
al~ays
the same.
At that
time
the
FORMAT
command
is
not,
used any longer since the diskette in drive
one is unusab
1
e.
"-
/
Page
15-02
\
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