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GENERAL SYSTEM OPERATION
2.7 --
Diskette File Concepts
be ambiguous.
Thus,
the
suffix
is
used
to
differentiate
between
entries
with the same file name.
Usually,. suffixes
designate a particular format of the file.
Thus,
a
source
file
could
have
the
suffix
IISAII.
Its
assembled obJect
version could have the same file name
but
with
the
suffix
"LX",
and
its
executable
version could have the same file
name but with the suffix
"LO".
MDOS
commands usually
supply
an
appropriate
default
suffix
wnen
dealing with specific
f i 1
es.
If both file name and suffix are specified,
they must be
separated
by
a
pel'iod
<. >.
The following are examples of
valid file name
specifications
using
both
file
name
and
suffix:
BLOKEDIT.CM
Z.SA
PROC1. CF
DOCUMENT. Y
Since each diskette is a complete file system in itself,
with complete directory and system files,
it is
possible
to
have
directory entries with the same file names and suffixes
on sepal'ate diskettes.
Thus,
the
logical
unit
numbel'
is
required
to
uniquely
specify
a directory entry on
~
given
dl'ive.
Logical unit numbers
consist
of
a
single
decimal
digit
(0,
L
2,
or
3).
In most case.s,
MDOS
commands supply,a
default value for the logical unit numbel'.
If
a
pa~ticular
drive
must
be
identifiedJ
it must be entered by the operat·or
as a part of
t~e
file
name
specification.
Logical
unit
numbers
follow
either the file name or the suffix depending
on whether one or
both
are
specified.
The
logical
unit
number
must
be
separated
from
the
file name
o~
from the
suffix
by
a colon (:).
The following are examples
of
valid
file name specifications
u~ing
logical unit numbers.
2.7.
1.
1
Fami
ly
names
BLOKEDIT.
CM:O
TEST. X: 1
DIR: 1
Z456.D3:3
ASM:2
Some
commands allow the operatol' to specify a family of
file names.
Family indicators can occur in either
the
file
name
or
the
suffix.
An
asterisk
<*)
is used as a family
indicator.
The family indicator represents all or part of
a
file name or suffix.
For exampleJ
FILE.
*
would
be
a
file
name
spacirication
that
includes
all
Page
02-13
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