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BACKUP COMMAND
3.7 --
Messages
OFFSET
i i
DR<s-unit/-Jj DR<d-unit>-kk
This indicates which bytes did not compare
du~ing
the vel'
i
r
y
p
~ 0
c
e s s .
The
II
i i"
i
s the
hex
a dec i ma
1
orfset
into
the sector,
II
JJ
II
is the hexadecimal
contents of the byte on the source unit <s-unit>,
ukk
lt
is
the hexadecimal contents of the
b~te
on
the destination unit <d-unit>.
DIRECTORY READ/WRITE ERROR
This indicates that an internal system error
was
encountered
Ulhile trying to access ·the directory
of
the source
diskette.
Errors
OT
this
type
indicate
a
possible hardware problem.
SOURCE FILE COPY ERROR
This
indicates that an internal system error was
encountered while reading
a Retrieval Information
Block from a file on the source diskette.
Errors
of
this
t~pe
indicate
a
possible
hardware
prob
lem.
INVALID TO COPY/VERIFY FROM DOUBLE TO SINGLE SIDED
This
indicates
that
on an
EXORdisk
III. system,
the source diskette was
double-sided
while
the
destination
diskette
was single-sided.
This is
invalid.
3.8 Precautions with BACKUP
The rollowing sections describe some
or
the
precautions
that
should
be
taken
when using the BACKUP command in the
various environments that are supported by MDOS.
3.8. 1
BACKUP and the
CHAIN
process
Since the
BAC~UP
command has
so
many
dirferent
paths
that
can
be
taken,
it is generally recommended that BACKUP
not be invoked from within a CHAIN process
~see
Chapter
6).
The
BACKUP
process
is
so
important
to the protection of
diskette files that the entire process should
be
supervised
by
the operatoT'.
Diskette
verification from within a
CHAIN
process using
the
BACKUP
command
is
also
infeasible.
The
CHAIN
command
writes intermediate information to the diskette
in
drive zero
during its operation.
Thus,
if
BACKUP
with the
"V"
option is
invoked
from
within
a
CHAIN process, and if drive zero is
involved in the BACKUP process,
then the
two
diskettes
are
Page
03-17
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