Radio Shack TRS-80 Trsdos & Disk Basic Reference Manual page 36

TRSDOS
Overview
One
advantage of
this
usage
is
that
anyone
looking
at a
directory
listing
of a diskette
will
know
what
kinds of programs
he's
looking
at.
Another
advantage
is
that
TRSDOS
is
equipped
to recognize
certain extensions.
For example,
if
a
file
has the extension
/CMD,
then
TRSDOS
will
load
and attempt
to
execute
that
file
when
you
type:
filename \l?lt*\A
omitting the extension
/CMD.
That's
why
you
can execute the
file
BASIC/CMD
by typing
BRsic
nana
Similarly,
your
own
programs can be written
to recognize
extensions.
More
on
Drive
Specifications
If
you
give a drive specification,
TRSDOS
will
use the
specified
drive in
executing the
command.
If
you
omit
a
drivespec,
TRSDOS
will
search through the
directories
of
all
drives in use,
starting
with
drive
0;
the
first
drive
with
the correct
name/
extension
wiil
be used.
However,
if
the
command
requires a
file
creation,
TRSDOS
will
skip
over
to
the
first
non
write-protected
diskette.
For example, suppose four
files
named
DRIVECHK
are
contained
on
drives
through
3.
Then
every reference
to
DRIVECHK
(no
drivespec)
would
go
to drive
0.
The
filespecs
DRIVECHK:0,
DRIVECHK:
1,
DRIVECHK:2, DRIVECHK:3,
would
allow each
of the four
files
to
be
accessed.
More
on Passwords
The
password
is
assigned
when
the
file
is
created,
and
may
be
changed
via
the
ATTRIB
or
PROT
commands.
Files
with
passwords can only be
accessed
by
reference to the
password, or
to the
diskette's
Master Password. So
if
you
assign a
password
to
a
file,
don't forget
it!
It's
important
to realize that
every
file
has
a
password, even
if
you
do
not
specify
it
explicitly
when
the
file
is
created.
In
such
cases,
a
field
of
8
blanks
becomes
the password.
3-8