Radio Shack TRS-80 model III Owner's Manual page 31

TRS-80
MODEL
III
DISK
SYSTEM
Anytime trsdos
has
to
open
a
file
(e.g., to
list
it
for you),
it
will
follow
the
same
sequence.
When
trsdos
has
to
write a
file,
it
will
skip over any write-
protected
diskettes.
Password
You
can
protect a
file
from
unauthorized access and
use
by
assigning
passwords
to
the
file.
That way,
a
person cannot
gain access
to
a
file
without using
the
appropriate password.
It's
important
to realize that
every
file
has
a
password, even
if
you
didn't specify
it
when
the
file
was
created. In
such
instances, the
password
becomes
eight
blank spaces. In
this
case, the
file
becomes
unprotected
—
anyone
can gain
total
access
simply
by
referring to
the filename.
trsdos allows
you
to
assign
two passwords
to
a
file:
•
An
"Update word," which
grants
total
access
to
the information
•
An
"Access word," which
grants limited access
to
the information
(see
attrib)
When
you
create a
file,
the
Update and Access words
are
both
set
equal
to the
password you
specify.
You
can change
them
later
with
the
attrib
command.
A
password
consists
of
a
period followed
by one
to
eight
letters
or
numbers.
If
you do
not assign a
password
to a
file,
trsdos
uses a default
password of
eight
blanks.
For example, suppose
you
have
a
file
named
secret/bas. and
the
file
has
myname
as
an update and
access
word.
Then
the
command: KILL SECRETS/
BAS
will
not cause the
file
to
be
killed.
You
must
include
the
password
myname
in
the
file
specification.
Suppose
a
file is
named
domain/bas and
has blanks
for the
password.
Then
the
command: KILL DOMAIN/BAS*GUESS
will not
be obeyed,
since
guess
is
not
the
password.
A
Few
Important
Definitions
System
vs.
Data
Diskettes
A
system
diskette
is
one which
contains
the
trsdos
disk operating system
software. Subject
to
space
limitations,
it
may
also contain
your
own
files.
A
system
diskette
must always be
in
Drive while
the
Computer
is
in
use.
A
data diskette,
on
the other
hand, does
not contain the operating
system
software,
and
therefore
cannot be used
in
Drive
0.
It
may
be used
in
Drive
1
,
2
or
3.
Such
a diskette
has a
maximum
of space available for storing
your
own
programs and
data.
24